PROCEEDINGS OF
MICROWAVE
2010
Cerritos, California October 21-24
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PROCEEDINGS OF
MICROWAVE
2010
Cerritos, California October 21-24
Published by:
ARRL AMATEUR RADIO The national association for
Copyright 2010 by The American Radio Relay League, Inc. Copyright secured under the Pan-American Convention International Copyright secured All rights reserved. No part of this work may be reproduced in any form except by written permission of the publisher. All rights of translation reserved. Printed in USA Quedan reservados todos los derechos
First Edition
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Welcome to Microwave Update 2010 Hosted by San Bernardino Microwave Society And San Diego Microwave Group
Welcome to all the microwavers around the world, 25 years of M.U.D. This year the San Bernardino Microwave Society And San Diego Microwave Group bring you the world’s most prominent Microwave conference, there will be Talks ,antenna range, Swap meet and vendors We have a very good line up for you and hope you enjoy I would like to give a special thanks to DICK KOLBLY K6HIJ who we lost just recently Dick was not much into operating, but was a most appreciated asset to the SBMS and the microwave world, Dick was always willing to go out of his way to help anyone who wanted it, and never asking for anything in return, DICK you will be missed The following people have made this conference and proceedings outstanding N6RMJ K6JEY WB6CWN WA6CGR WA6JBD Phyllis Kolbly KH6WZ KC6QHP WB6DNX W6OYJ N6IZN
Chairman CO - Chairman Speakers \ Proceedings Prizes \ Testing Surplus Tour \ Testing Registration Publicity JPL Tour Vendors Antenna Testing Antenna Testing
A special thanks to the ladies for putting on the family program There is a lot more people who have helped to put this on, Thank You SBMS and SDMG Pat N6RMJ
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History of Microwave Update by Al Ward W5LUA August 2010 Edition In 1985, Don Hilliard, WØPW, felt the need to organize a conference dedicated to microwave equipment design, construction, and operation. At the time of its conception, many microwave terrestrial and EME firsts were occurring on the microwave bands and it appeared that microwave needed a dedicated conference. Don held the first conference which he named “The 1296 and 2304 MHz Conference.” It was held at the Holiday Inn in Estes Park, Colorado. 66 people were in attendance. It sure seemed like Don was on the right track with his idea and he was right. In 1986, Don held the second conference which he rightfully named “Microwave Update 86.” 64 people were in attendance. The 1987 and 1988 “Microwave Update” conferences were again held in Estes Park, CO. and chaired by Don Hilliard. After putting on 4 fine conferences in Colorado, Don decided to take a break from all of the work. Don turned over the responsibility of coordinating the event to the North Texas Microwave Society (NTMS). In 1989, WB5LUA and WA5VJB of the NTMS hosted the 5th “Microwave Update” in Arlington, Texas where 94 people were in attendance. The 1990 “Microwave Update” was to go back to Colorado where Keith Ericson, KØKE and Don Lund , WAØIQN, were to head up the event. Unfortunately, Don Lund passed away during the year and Keith decided to postpone the 1990 Update. WB5LUA and WA5VJB of the NTMS hosted “Microwave Update” 91 in Arlington, Texas. “Microwave Update” ’92 was held in Rochester, New York and sponsored by the Rochester VHF Group. The conference was chaired by Frank Pollino, K2OS and Dave Hallidy, K2DH (x KD5RO/2). “Microwave Update” ’93 was held in Atlanta, Georgia. The conference was organized by Jim Davey, WA8NLC, and assisted by Rick Campbell, KK7B and Charles Osborne, WD4MBK. “Microwave Update” ’94 was brought back to Estes Park, Colorado where it was chaired by Bill McCaa, KØRZ. Bill was assisted by Al Ward, WB5LUA, Jim Davey, WA8NLC, Jim Starkey, WØKJY, Phil Gabriel, AAØBR, and other local area amateurs. “Microwave Update” ’95 was brought back to Arlington, Texas and was chaired by Al Ward, WB5LUA and Kent Britain, WA5VJB of the NTMS. The ’96 “Microwave Update” was held in Phoenix, Arizona and was chaired by Jim Vogler, WA7CJO. The ’97 “Microwave Update” was held in Sandusky, Ohio and sponsored by Tom Whitted, WA8WZG, with the assistance of Tony Emanuele, WA8RJF. The 1998 “Microwave Update” was held in Colorado under the guidance of Bill McCae, KØRZ, and John Anderson, WD4MUO. The 1999 “Microwave Update” was held in Plano, Texas with Al Ward, W5LUA and Kent Britain, WA5VJB hosting the event. The 2000 Microwave Update was held in the Philadelphia area with John Sortor, KB3XG, and Paul Drexler, W2PED hosting the event. The 2001 Microwave Update was hosted by Jim Moss, N9JIM and Will Jensby, WØEOM, in the Sunnyvale, California area. The 2002 conference was held in conjunction with the Eastern VHF/UHF Conference in Enfield, CT. The conference was hosted by Paul Wade, W1GHZ, Matt Reilly, KB1VC, Tom Williams, WA1MBA and Bruce Wood, N2LIV. The 2003 conference moved across country to Seattle, WA where Rick Beatty, NU7Z and the PNWVHFS hosted the event. Rick’s committee consisted of John N7MWV as the co-chairman along with Jim K7ND, Eric N7EPD, Jim, W7DHC, Jimmy, K7NQ, and Lynn, N7CFO. The 2004 conference was held in Dallas, Texas where Al Ward, W5LUA, Bob Gormley, WA5YWC, Kent Britain, WA5VJB, and the North Texas Microwave Society hosted the event.
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The 2005 conference was held in Cerritos, CA. The event was hosted by Pat Coker, N6RMJ and Chip Angle, N6CA ,along with the San Bernardino Microwave Society and the Western States Weak Signal Society. The 2006 conference was held in Dayton, Ohio and was hosted by Tom Holmes, N8ZM, and Gerd Schrick, WB8IFM of the Midwest VHF/UHF Society. The 2007 conference was held in Valley Forge, PA at the Dolce Valley Forge. The conference was hosted by Phil Theis, K3TUF, David Fleming, KB3HCL, Rick Rosen, K1DS, and Paul Drexler, W2PED of the Mt Airy VHF Radio Club. The 2008 conference was hosted by Donn Baker, WA2VOI, Barry Malowanchuk, VE4MA, Jon Platt, W0ZQ, Bruce Richardson, W9FZ, Bob Wesslund, WØAUS, of the Northern Lights Radio Society and was held in Bloomington, MN. The 2009 conference was held in Dallas, Texas and was hosted by Steve Hicks, N5AC, Al Ward, W5LUA, Bob Gormley, WA5YWC, and Kent Britain, WA5VJB, of the North Texas Microwave Society. In 2009, The Don Hilliard Technical Achievement Award was created in honor of our founding father Don Hilliard, WØPW. The first recipient was Paul Wade, W1GHZ, in recognition of his many years of service to the amateur microwave community. The 2010 conference is being hosted by the San Bernardino Microwave Society in Southern California. The 2011 conference will be hosted by the North East Weak Signal Group. Those that are interested in sponsoring a conference may contact myself, Al Ward, W5LUA or Kent Britain, WA5VJB. Respectfully Submitted, Al Ward, W5LUA 08-30-2010
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The Don Hilliard Technical Achievement Award Don Hilliard, WØPW, (exWØEYE) an early VHF pioneer was involved with the formation of the Central States VHF Society back in 1967. The Central States VHF Society was and still is very instrumental in promoting VHF and above activity. Back in 1985, Don realized that there was a considerable thrust in new microwave technology above 902 MHz. As a result, Don felt the need to have a conference devoted to the higher frequencies. The conference would be devoted to microwave equipment design, construction, and operation. At the time of its conception, many microwave terrestrial and EME firsts were occurring on the microwave bands and it truly appeared that microwave needed a dedicated conference. Don organized the first conference which he named “The 1296 and 2304 MHz Conference”. It was held at the Holiday Inn in Estes Park, Colorado. 66 people were in attendance. It sure seemed like Don was on the right track with his idea and he was right. In 1986, Don held the second conference which he rightfully named “Microwave Update 86.” 64 people were in attendance. The 1987 and 1988 “Microwave Update” conferences were again held in Estes Park, Co. and chaired by Don Hilliard. After putting on 4 fine conferences in Colorado, Don decided to take a break from all of the work. Don turned over the responsibility of coordinating the event to the North Texas Microwave Society (NTMS). The rest is history. With the exception of one year where one of the organizers, Don Lund passed away, Microwave Update has been held every year. To this date including the 2009 conference being held in Irving, Texas, Microwave Update has been hosted 24 times. The conference has been successfully organized and run by various local VHF and microwave clubs and groups around the US. In tribute to Don Hilliard and his tremendous contributions to VHF and microwave technology and for appreciation of his forward looking into the fascinating world of “microwaves,” the North Texas Microwave Society on behalf of Microwave Update would like to create “The Don Hilliard Technical Achievement Award” presented each year to an amateur radio operator who has made significant contributions to amateur microwave operation and technology. The NTMS proposes that this award be presented to a deserving amateur each year by each sponsoring organization. Respectfully submitted Al Ward W5LUA Kent Britain WA5VJB Steve Hicks N5AC September 9, 2009
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Table of Contents Welcome ....................................................................................................................................... iii History of Microwave Update ...................................................................................................... iv Don Hillard Award ....................................................................................................................... vi Introduction to Hot Rod Microwave Radios; Rick Campbell, KK7B ............................................1 Hot Rod Radio for 5760; Rick Campbell, KK7B ...........................................................................6 A 432/1296 MHz SSB/CW Direction Conversion Transceiver; Jim Davey, K8RZ ....................15 How to Increase 23 cm Power to 250W with 2 x XRF 286, Some Modifications to the W6PQL Kit; Dominique Faessler, HB9BBD ...................................................................22 2010 Observations on Phase Noise from Local Oscillator Strings; Gerald Johnson, KØCQ .......28 Safe Tapping in Soft Metals; Gerald Johnson, KØCQ .................................................................30 Taming Phase Noise at EHF; Brian Justin, WA1ZMS/4 ..............................................................34 Ka-Band Integrated-Circuit Interferometer for Sensing; Seok-Tae Kim and Cam Nguyen .........39 A Novel Approach to a Multiband Transverter Design; Jeff Kruth, WA3ZKR ...........................42 A YIG Filter Primer & Simple Driver Circuit for HAM Projects; Jeff Kruth, WA3ZKR ...........56 LO Phase Noise Effects on MDS; Gary Lauterbach, AD6FP ......................................................64 A Modern 47 GHz Transverter; Tony Long, KC6QHP ...............................................................76 NJR2145J 10 GHz Pre-amplifier Adaptation and Construction; Gary Lopes, WA6MEM ..........87 Propagation Observations with the 10 & 24 GHz VE4 Beacons; Barry Malowanchuk. VE4MA ..........................................................................................94 PIC’n on the ThunderBolt; John Maetta, N6VMO .....................................................................109 Development of an UWB CMOS Transmitter-Antenna Module; Meng Miao and Cam Nguyen .........................................................................................112 Frequency Stability Measurement: Technologies, Trends, and Tricks; John Miles, KE5FX .....116 Compass Basics And Some Representative Types; Doug Millar, K6JEY .................................134
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Signal Level Meter Throw Down; Doug Millar, K6JEY ...........................................................140 C-Band LNB to LNA Conversion; Christian Shoaff, N9RIN ....................................................144 A Personal Beacon for 10 GHz (That Can’t Possibly Work); Paul Wade, W1GHZ ..................149 High-Power Directional Couplers with Excellent Performance; That You Can Build; Paul Wade, W1GHZ .......................................................................................................152 Analysis of the WA1MBA 78 GHz Low Noise Amplifiers; Al Ward, W5LUA .......................167 Moving Ahead with the 78 GHz Low Noise Amplifier Project; Tom Williams, WA1MBA .....173 An Improved 2 x MRF286 Power Amplifier for 1296 MHz; Darrell Ward, VE1ALQ .............175 Modifying a DMC Dielectric Resonator Oscillator for Amateur 10 GHz Use; Brian Yee ........184 Connectorize Your IF Radio!; Wayne Yoshida, KH6WZ ..........................................................190 Working on the Microwaves: Seeing is Believing; Gene Zimmerman, W3ZZ, and David Mertz, WA3OFF ...........................................................................................191 Physical Optics Demonstrations with Microwave ......................................................................204 Noise Figure Measurements 2009 ..............................................................................................215
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Introduction to Hot Rod Microwave Radios Rick Campbell KK7B The following essays and projects illustrate a different approach to Amateur Microwave Radio, an undisciplined, enthusiasticly attention-deficit creative process loosely defined as “Stuff we do because it’s Cool.” These projects don’t increase frequency, reduce noise temperature, or chop signals to bits and reassemble them in some alternate domain. They are unconstrained by rules for coloring in squares on a map or counting the distant nerds one can greet in a weekend. These aren’t the microphones to grab in an emergency or broadband pipelines for 3-D real-time holographic video. But as design exercises they have stretched our limits and as construction projects they have forced us to learn new skills and refresh old ones. College engineering students find them irresistable. Have fun, and don’t take this stuff too seriously. Hot Rod Radios My friends and I find many attractions in Microwave Amateur Radio: pushing upper frequency limits, competition, radio science, and a love affair with the technology. Other papers in this digest are devoted to extending the state-of-the-art into micron-dimension waveguide bands, and we apply radio science every time we scatter a signal off some hard object or atmospheric anomaly to add a far-off grid to our cumulative total or contest score. This set of papers addresses a life-long love affair with the technology. Lifting the covers to see what’s inside a radio and figure out how it works was our original attraction, and it has stayed with us for half a century. As such, it provides a key to attracting and retaining the next generation of radio amateurs, scientists, technologists, and general technical problem solvers. Society needs other contributors, so if your natural tendencies involve compassion, fixing cuts and bruises, caring for animals, or bossing around other people based on your interpretation of the fine print in some law-don’t feel bad. Society has a place for you too. That fine print gives us access to our slices of spectrum. Jim Davey and I both have roots in Michigan. My grandfather took me to the Ford Rotunda for the world premier auto show every year as a child, and at an early age I knew the difference between a concept car, a test track vehicle, and the family car we drove to the Great Scot store. My father walked the family through the Edison Institute and Henry Ford Museum more times than I can count. We wandered through the evolution of ideas and products as they drifted off on bizarre styling tangents and offered new approaches to a changing national landscape. Along with the other boys of the time, we viewed the family car as a collection of parts that could be reassembled into something Really Cool if only our dads would let us. I have no idea what girls at the time thought-I still don’t. It’s a mystery. We played with Erector Sets and Knight-Kit 12-in-1 labs, following our imaginations along ten impractical paths for every one that actually led somewhere. An Amateur Radio License allows us to design and build our own gear, which has always seemed to me to be more significant than making contacts. We lured
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unsuspecting Heathkits into dad’s shop and hacked and modified them into creations that sometimes worked almost as well as the originals. Our high-school classmates drove Hot Rod cars, and we squeezed 100 watts out of a single 6146. Briefly. It has been with some dismay that I have observed a flood of nostalgia for the unmodified radios of the past. They retain some of the romance generated by glossy ads in the back of the 1962 ARRL Handbook--but most of their personal appeal is still as a collection of parts that could be transformed into something Really Cool. My personal definition of Really Cool has often included operating on a higher frequency, hence my decade of contributions to the early years of this conference. Others have alternate definitions. My good friend Wes Hayward thinks Really Cool is a collection of individual components from the Tektronix Surplus Store, assembled on scraps of unetched circuit board, spread over the bench, and outperforming the $1000 appliance pushed to the back of the operating table/work bench. We’ll use that diversity as the first premise of Hot Rod Radio: 1. Hot Rot Radios are Really Cool--but acknowledge that the appeal may be limited. You may think my creations are merely strange. The second premise of Hot Rod Radios is that they exhibit individual creative contributions of the designer/builder/owner/operator. A simple hack isn’t enough--particularly a non-invasive, fully recoverable mod that can easily be reversed so that the rig appears original. I admit that years ago I caught a moderate case of Vintage Disease, and I have trouble drilling a hole in the front panel of a rare 1960 era radio. But I have no such qualms about ripping out all the guts and adding good connectors to the rear deck. So the next premise is: 2. Hot Rod Radios are exhibit enthusiastic, individualistic modifications. My goal is for the KK7B Hot Rod version of the family radio to have more appeal and higher street value than an unmodified stock example in good condition...at least, to me. Mint condition examples of even common, low cost radios should be left alone. There is some unwritten rule about that, and it is a good one to follow. Trade the mint example to a collector for two of the same model in modest condition. If basic performance is adequate, additional hardware can be added to enhance performance, or interface to microwave transverters. Recently I’ve been gutting simple radios with appealing cases and linear mechanical tuning mechanisms, and building a high performance analog radio in the box. Then I interface the radio with some additional gear--usually vintage homebrew--and use it on the air. My Hot Rod creations aren’t just art objects, they are street legal and operate well enough to be fun. That’s the third premise: 3. Hot Rod Radios perform well for a specific, often challenging technical function. In fact, all of my Hod Rod versions outperform anything commercially available on the specific bands and modes for which they were conceived, designed, and built.
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Transforming a 1950s family sedan into a 1960s Hot Rod involved the sacrifice of some family sedan features: beige paint, automatic transmission, back seat, muffler--to gain performance in a particular area, primarily attracting the attention of girls. Since guys have no idea how to attract girls, they settle for the next best thing: intimidating other guys. That makes them feel cool. Guys who think they are cool radiate some kind of gas that lowers common sense. So by default, pretty girls end up sitting in the coolest cars. Briefly.
Photo 1. A drool-inducing package enclosing a truly marginal receiver. But appearance is deceiving. Under this mild-mannered exterior purrs a high-end R2pro receiver used as a high performance microwave IF.
Photo 2. A peek under the hood at the new high-stability VFO
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Since electronics radiate some kind of consciousness-raising gas, radios have limited use in attracting girls. From observing my daughters I suspect that the mere existence of a radio as the object of a guy’s attention has an anti aphrodisiac effect. This is perhaps universal across many species. One could observe moose with radio collars... That is a fundamental difference between Hot Rod cars and Hot Rod radios. The designer/builder of a Hot Rod car expects some of the coolness to rub off on him. The Hot Rod radio designer has no such illusions. The radio is Cool, all by itself. That is enough. That is the final premise of Hot Rod radios: 4. There is no ulterior motive. A Hot Rod Radio is complete, in itself, creating its own context. It just sits there, being Really Cool. It is Art.
Photo 3. A Hot-Rod 6m SSB transmitter-Receiver in a Heathkit Q-Multiplier case, with styling cues from the E F Johnson Ranger. This radio takes 6m about as seriously as I do, but even non-hams think it is cute. After a decade of using an Eddystone Dial for tuning the home microwave station, I have reverted to analog, mechanical dials whenever practical. I use an analog mechanism to steer my car too. I won’t be replacing it with a computer anytime soon. I can’t quite put my finger on the appeal of this radio, but a quote from the poet Nelson Bentley comes to mind: “I have this sneaking suspicion that not everything is always happening in the present tense.”
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My creative thoughts originate outside engineering. On my writing desk are collections of boat designs by the late Phil Bolger and poems by the late Nelson Bentley. The Hot Rod creations of the late Ed “Big Daddy” Roth inspired a generation of kids to question convention. A Hot Rod Radio inspires kids and old men to dig the old dusty shortwave set out of the garage and fill the notebook with ideas and sketches. That is enough. Sudoku for nerds. If it gets built, fine--but we develop technical problem solving skills as much by practicing the art of design as by cutting metal. Make ten sketches for every complete design, and design ten for every one you build. Build one a year. That has been my habit. This essay was inspired by friends who mess around with Radio Frequency Electronics, in particular my close collaborators for decades: Jim Davey, Wes Hayward and Merle Cox. Although some of the text has been gender-specific, I’d like to also acknowledge the influence on my work of two women as fluent with Smith Charts as any of my male professional colleagues: Allison Parent and Lorene Samoska. Their creations in the radio arts are Totally Cool.
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Hot Rod Radio for 5760 Some Thoughts on Packaging Amateur Microwave Systems Rick Campbell KK7B
Photo 1. Classic-Deluxe 5760 Station, set up on the picnic table in the back yard at KK7B. The modular black-box 144 MHz rig on top of the SX-140mkII contains a T2 exciter, LM2 VXO system, R2pro receiver, and CDS Cell based Audio AGC system. The 1296 IF transverter is visible behind the microphone, on top of the 5760 transverter. For anyone experienced with HF operation using an old SX-140 HF receiver, this appears to be a rather marginal microwave station. Looks can be deceiving...
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The only original equipment inside the SX-140 case is the slide rule dial and a set of air-variable VFO capacitors. A frequency compensated JFET Hartley VFO is inside the small black die-cast box. After a brief warmup, it drifts less than 100 Hz per hour, and tuning with the large dial is silky smooth.
Photo 2. Inside the SX-140 case, showing all the room available for IF converters. This set of projects was assembled after Jim Davey and I started kicking around the idea of Hot Rod Radios--gear that displays a bit of whimsy and more than a little Art. For this particular application, the SX-140 tunable IF is used as the receive portion of a microwave system with most of the microwave hardware at the feed point. The trasmitter is a VXO controlled phasing system operating directly on 144.1 MHz, with a second 144 MHz R2pro receiver slaved to the transmitter. A switch selects either receiver. For portable operation with space limitations, the SX-140 may be left at home, and the rest of the system is still fully operational. A coax relay selects the active receiver, controlled by one of the red switches on the front panel of the SX-140. The 144 MHz receive converter (a Kanga Rcx2 module not shown in this photo) is fastened to the top of the chassis with double-sided tape. Power is 12 volts DC, and power supplies are remote. Although there is space, mounting the power supply in the receiver limits flexibility and introduces hum in the sensitive audio electronics.
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Photo 3. Under the chassis is a set of R2pro receiver modules, also available from Kanga US. After selecting the appropriate sideband using jumpers and tweaking the alignment, the receiver will work forever without adjustment. Other modules in the system are designed for similar set-and-forget utility. Reconfiguring the receiver for 6m, Straight Key Night on 40m, adding the 7 MHz SSB exciter etc. involves simply swapping modules above the chassis. For several decades the approach to microwave operation at KK7B has focused on portable operation with modular equipment. As a receiver designer, I have never been satisfied with the performance compromises in commercial VHF gear. After designing and building my first serious HF receivers in the early 1990s, that discomfort extended to HF equipment as well. I sold the Collins gear, relegated the Racal RA-6790/gm to the lab bench, and sketched receiver designs for my bands of interest. Although an HF receiver might not qualify as Microwave Gear, it really is the core of my microwave station. Filters, noise floor, gain distribution, dynamic range, and stability are all designed specifically to meet my weak-signal microwave IF needs. Once I have selected the receiver core, I add an assortment of modules to meet performance requirements on a particular band. One lesson I have to keep re-learning is not to put too many functions into any one module. This receiver gets used all the time, specifically because it is flexible.
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Creative packaging, or Thinking Inside the Box. Some very interesting microwave paths are far from my home QTH in Portland Oregon...far enough that I might have to fly on a commercial airplane to get there. Since anything cylindrical and electric looks suspicious on a Committee for State Security X-Ray machine, it is better to ship the microwave gear by alternate means. After a decade of carefully packing and mailing my electronic gear, I realized that Flat-Rate Priority Mail boxes make nice transverter boxes. If the Flat-Rate box IS the radio, I don’t even have to unpack the gear.
Photo 4. An entirely conventional 1296 IF transverter. TUF-15 mixer on the left, a pair of 1296 Ace Hardware filters, two SMA relays, and two VNA-25 amplifiers. The DC electronics on the board convinces the latching relays to switch. It works, but not well enough for me to want anyone to duplicate the circuit. The Priority Mail box in the background is the packaged 5760 Transverter, all set to drop in the mail to Annapolis, MD. Not shown is a second Priorty Mail box with foam inserts that contains the 1296 transverter and 144 MHz VXO IF rig. For less than the price of a checked bag, the complete microwave station is waiting for me when I step off the plane.
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Photo 5. Here’s the inside of the Medium Sized USPS Flat-Rate box containing the 5760 transverter and horn antenna. Some of the packing foam has been removed to take the photo. In normal operation the box is sealed shut, with only the 12 DC power and 1296 IF cable leaving through the upper left corner. The 17 dBi horn antenna shines out the lower right corner of the box, and may be used alone or to illuminate an offset dish or flyswatter. Out to 4 miles or so the barefoot horn is plenty. The 5760 transverter was as described in QST over 20 years ago, and stability enhancement was described last year at Microwave Update 2009.. Long ago I adopted the practice of building up complete portable stations for single bands, packaging them up in a cardboard box with a cover, and leaving them on a shelf in the garage. Some of them weren’t used for ten years, as my children navigated high school and then college. But having them boxed up all ready to go meant that I could grab a 3456.1 SSB-CW station off the shelf, toss it in the car trunk, and not even look at it until I opened the box on the deck overlooking Pickering Passage at the W7YOZ QTH. Then I discovered that I had forgotten the cable adapter to connect the antenna. The above system addresses that issue. This rig has been ideal for tracking down 5.7 GHz noise and interference sources.
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After a decade of absense from the 6cm amateur band, it was a rude awakening to discover all of the interference from computers, cordless phones, and unmentionable personal devices. Even electric outboard motors communicate with on-board energy management systems using microwave links. Microwave operation on over-water paths accessible only by shallow draft boat is becoming more and more attractive. Some lakes and reservoirs discourage power boats with electronic ignition systems, and even some that don’t are large enough that it is possible to arrive at a location a mile from the nearest wall wart connected to a digital noise generator. Wind Power is The Latest Thing. Rather than convert it to electricity, I decided to use it to power my transportation. The fuel I save in the Honda Outboard could power my station, in principle. Here is a photo of KK7B heading out across Timothy Lake to scout a microwave site with a clear shot to the summit of Mount Hood.
Photo 6. The boat is home built, a Phil Bolger Nymph. The energy conversion system is my own design. She is not easy to sail, but she is a lot of fun--rather like making maritime mobile contacts on 5760.1 MHz. Photo by KB8FCZ. Operating on 5760.1 MHz SSB or CW from a small boat is interesting, to say the least. The Pacific Northwest has a plethora of knock-your-socks-off gorgeous over-water paths, some of them line-of-sight to mountain peak reflectors or well-equipped fixed stations. The bad news is that when the weather is that nice and you are out in a sailboat, the rig gets in the way... I’ve had a great time, but contacts have been sparse.
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Photo 7. A Nautical 5760.1 SSB-CW station tucked into the stern sheets of a small Gaff rigged sloop. The technical term is “Darned Cute.” The rig sits in the stern of the boat, tucked under the tiller. A horn antenna fits in the mount for the boom crutch, leaving the boom and gaff-rigged main sail flopping around the other side of the boat. This needs more work. I designed the packaging before I added the wind power system to the boat. Also note that the Horn antenna is vertical polarized in this photo. The rig has been completely described in QST, and is as much a Classic as the SX-140. It has been working without adjustment, since it was first built in 1990. It is one of the few pieces of electronic equipment I own that stands up well to operation in a bumpy, wet portable environment. The two 5760 rigs described here have approximately 10 dB noise figure and 0 dBm power output, which is enough for marginal SSB or reliable CW over a 10 mile overwater path. In the maritime mobile environment, the wide beamwidth of the +17 dBi horn antenna is a necessary feature. If more gain is needed, it belongs at the fixed end of the path.
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Photo 8. The view over the stern. Note the use of lashings instead of rigid fasteners. Everything flexes in a wooden boat, particularly anything you expect to be stiff. Bits of string and double-sided tape are usually superior to screws. The horn is also homebrew, and I wouldn’t build it the same way again. This is an old designer’s trick: provide just enough information to encourage someone to work the problem, but not enough that they will duplicate your mistakes. Sometimes it pays off and the next generation comes up with something much better. But you have to turn a deaf ear to the din of lesser talents demanding more construction detail. Most of the microwave bits are vintage KK7B no-tune transverters. They work well at sea-level, line-of-sight to another station, and miles away from the nearest RFI plagued urban hilltop. More recent gear handles the proliferation of commercial microwave energy better than quarter-century old first generation MMIC and bare PC board technology. Plans for the boat, a Phil Bolger designed Nymph are available from Phil Bolger and Friends. The wooden boat community is as focused and skilled as the amateur microwave community. Bob Larkin W7PUA also built and sails a Phil Bolger designed boat, the much larger Birdwatcher. You can find details on the web.
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Photo 9. A detail shot of the maritime mobile 5760.1 SSB-CW station. This station probably qualifies as Vintage Gear. The gray and black box in the lower left corner contains the original prototype KK7B 1296 No-TuneTransverter, as pictured on the cover of April 1993 QST and featured in several ARRL Handbooks. Invisible on top of the 1296 IF transverter is the original 5760 No-Tune Transverter, featured in QST October 1990. The gray and black box with all the switches and lights houses the original prototypes of the R2 and T2 rigs from January and March 1993 QST. Maybe this stuff should be in a museum instead of getting wet in the back of a boat. Just visible to the right of the premixed 144 MHz VFO (April 1993 QST) is the Navy Knob on an EF Johnson Key. I haven’t touched this stuff since it was built, and it still meets all the original specs. Few pieces of commercial gear from the early 1990s can make that claim. This has been a rather light-hearted look at microwave station packaging, with a bit of Pacific Northwest whimsy and art tossed into the mix. As amateurs, we have the luxury of following a different path--enclosing our microwave gear in a free cardboard box or a unique wooden sailboat. If you get bored with contests and grid collecting, try a quirky station package. These have been a lot of fun, and generated considerable interest.
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) !&!"&+2&!3 &! $$ =) &" )& &'" &!& >81 $&! !! 1&&"&&!2'&+3&)& $+!($"$+- ! )& $ = = !& 5kHz will help insure that all of the resulting noise at the output frequency of the PLL is truly a function of 20Log(n) of the applied reference frequency.
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Another fortunate outcome of using the ever common Frequency West or California Microwave PLL blocks as part of a mm-Wave LO chain is that their closed loop bandwidths are often several 10’s of kHz. This is very helpful in that it can be safely presumed that all of the phase noise at the output frequency of the PLL block for many kHz anyway from the carrier is directly following the 20Log(n) scaling factor. 6) 78GHz Example In this section an example LO chain for 78GHz is presented as shown in Figure 1 below. The figure denotes the overall LO chain as the reference oscillator (in this case, a 10MHz OCXO) signal is multiplied and increased in frequency towards the final LO frequency of 78.000GHz.
Figure 1 – Example of 78.000GHz LO chain showing the degradation of phase noise from each multiplier stage.
As the frequency is increased by a given multiplier stage, the effective increase in dB of phase noise is noted. For example, in the first multiplier stage the 10MHz reference is directly multiplied to 50MHz. This results in a phase noise degradation of 13.97dB which is a result of the 20Log (n) formula. As the LO frequency increases with each successive multiplier stage the phase noise continues to degrade. The result of this particular LO chain starting at 10MHz and progressing to 78.000GHz has a total of impact of 77.84dB on the phase noise of the frequency reference. This means that the phase noise of the 10MHz reference oscillator must be 77.84dB better than our minimum signal specification of -72dBc/Hz @ 1KHz offset. The required phase noise of the reference must then be (72 + 77.84) or -149.84dBc/Hz @ 1KHz. In the above case, the Frequency West PLL assembly has no worse impact on the phase noise of the LO so long as the bandwidth of the PLL is greater than the frequency offset range that we are interested in. Since our target offset frequency of interest is 1KHz (as
37
noted in section 3) and the PLL bandwidth (as noted in section 5) is at least an order of magnitude greater, there is no concern and the PLL will act just like a direct multiplier.
7) Conclusions From the example above it can be concluded that any 10MHz reference oscillator that has a phase noise specification between -149.84dBc/Hz and -125.84dBc/Hz at a 1kHz offset frequency would result in a 78GHz radio that has between 0 and 2dB of MDS impact respectively. It can also be concluded that the theoretical crystal oscillator specified in Table 1 above would in fact be quite usable as a reference oscillator in a 78GHz station. This oscillator would result in almost no detectable impact to ear-copy of a CW signal on the band. Keep in mind that narrower bandwidth modes (PSK-31, WSJT, QRSS, etc.) will require even lower values of phase noise and are purely dependant on the particular modulation mode in question. 8) References [1] – B. Justin, WA1ZMS, Microwave Update presentation, Dallas, TX, 2009.
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Ka-Band Integrated-Circuit Interferometer for Sensing Seok-Tae Kim and Cam Nguyen Department of Electrical and Computer Engineering Texas A&M University College Station, TX 77843 Abstract A multi-function millimeter-wave integrated-circuit sensor operating at 35.6 GHz has been developed and demonstrated for monitoring of displacement and low velocity. Measured displacement results show an unprecedented resolution of only 10 m, approximately equivalent to 0/840 in terms of free-space wavelength 0, with a maximum error of only 27 m. The sensor can measure speed as low as 27.7 mm/s, corresponding to 6.6 Hz in Doppler frequency, with an estimated velocity resolution of 2.7 mm/s. 1. Introduction Microwave and millimeter-wave interferometry has been widely used for various applications such as position sensing [1], velocity profile [2]-[3], and displacement measurement [3]-[4]. Interferometry is basically a phase-sensitive detection process, capable of resolving any measured physical quantity within a fraction of the operating wavelength. Interferometric sensors also have relatively faster system response time than other sensors due to the fact that they are generally operated with single-frequency sources. Millimeter-wave interferometer is thus an attractive instrument for various engineering applications requiring fine resolution and fast response. In this paper, we report on the development of a multi-function millimeter-wave integrated-circuit sensor capable of measuring both displacement and velocity (particularly low velocity), based on phase detection, for potential industrial applications. For displacement sensing, the sensor achieves a resolution and maximum error of only 10 and 27 m at 35.6 GHz, respectively. The attained resolution, approximately equal to 0/840, is the best reported resolution in terms of wavelength. The sensor can measure speed as low as 27.7 mm/s, corresponding to 6.6 Hz in Doppler frequency, with an estimated velocity resolution of 2.7 mm/s. 2. System Principle The overall system configuration is shown in Fig. 1. The system is divided into three parts: a millimeterwave subsystem for processing millimeter-wave signal, an intermediate-signal subsystem for processing signals at intermediate frequencies, and a digital signal processor. The sensor transmits a millimeter-wave signal toward a target. The signal reflected from the target is captured and directed to the receiver, and down-converted to a low-frequency signal, namely the measurement-channel signal vM(t), which contains information on the phase or phase change over time generated by the target displacement or movement, respectively. For displacement measurement, the measured phase of vM(t) is compared with that of the reference-channel signal, vR(t), coming from the direct digital synthesizer (DDS). If the target is in motion, the frequency of vM(t) is shifted by the Doppler frequency. In velocity measurement, the phase change over time is detected in the signal processing and only measurement-channel signal is processed to extract the Doppler frequency shift. The sensor’s signal processing consists of two distinct parts: one for detecting the phase difference needed for measuring the displacement and another one for estimating the Doppler frequency used for calculating the velocity.
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PLO-1
1.5m fEXT=17.8 GHz
× 2 Frequency Doubler
Directional Lens Horn Coupler Antenna fC= 35.6 GHz
PA Power Amp.
Target
XYZ axis Stage
Power Divider
Conveyor
Down Converter
LNA Up Converter
BPF LNA
RF_OUT
MMW Subsystem
RF_IN
AMP
AMP
PLO-2 fIF1=1.8GHz
Fig. 1 Overall system block diagram. The target sits either on the XYZ axis (for displacement sensing) or on the conveyor (for velocity measurement). The Reference Channel is not needed for velocity measurement.
Mea. Ch. AMP
Digital Signal Processor
Down Converter AMP
Quadrature Up Converter
Intermediate Subsystem
Ref. Ch.
DDS fIF2= 50 kHz
3. Fabrication and Test
(a)
(b)
Fig. 2 Photograph of the fabricated millimeter-wave (a) and intermediate-signal (b) subsystems. The millimeter-wave and intermediate-signal subsystems, shown in Fig. 2, were realized using both MICs and MMICs. We have tested the developed sensor for measuring the displacement of a metal plate mounted on a XYZ axis stage. Fig. 3 shows the measured displacement along with error. The result indicates that a resolution of only 10 m, equivalent to about 0/840, is attained. We have tested the velocity of a closing metal-plate target. The experimental results are shown in Fig. 4. The average measured velocities are 27.7, 32.6 and 38.6 mm/s. The corresponding standard deviation of the Doppler frequency estimates are inferred as 0.50, 0.61 and 0.64 Hz, respectively.
40
0.008
16
45
0.007
15
40
0.25
14
0.005 0.004
0.15 0.003 0.10
Error (mm)
Measured (mm)
0.20
0.002
0.05
0.10
0.15
0.20
0.25
30
12 11
25
10
20
9
15
8 7
0.000
6
-0.001 0.30
35
13
0.001 0.05
0.00 0.00
Doppler frequency (Hz)
0.006
10 5
5
0 1
2
Displacement (mm)
Fig. 3 Measured displacement every 10 m.
Velocity (mm/s)
0.30
3
4
5
Measurement index
Fig. 4 Measured velocity of a closing target. 4. Conclusion
A multi-function millimeter-wave integrated-circuit sensor operating at 35.6 GHz has been developed and demonstrated for displacement sensing, with micron resolution and accuracy, and for high-resolution lowvelocity measurement. Displacement measurement results indicate that the sensor can resolve displacement within 10 m or 0/840, which represents the best-reported resolution in terms of wavelength in the millimeter wave range. Velocity as low as 27.7 mm/s, equivalent to 6.6 Hz in terms of Doppler frequency, has been measured at 35.6 GHz for a moving target. The developed sensor demonstrates that displacement sensing with micron resolution and accuracy and high-resolution lowvelocity measurement are feasible using millimeter-wave interferometer, which is attractive not only for displacement and velocity measurement, but also for other industrial sensing applications requiring very fine resolution and accuracy. Acknowledgement This work was supported in part by the National Science Foundation and in part by the National Academy of Sciences. References [1] A. Stelzer, C.G. Diskus, K. Lubke, H.W. Thim, “Microwave Position Sensor with Submillimeter Accuracy,” IEEE Trans. Microwave Theory Tech., vol. 47, no. 12, pp. 2621–2624, Dec.1999. [2] A Benlarbi, J.C Van De Velde, D. Matton, Leroy, Y., “Position, Velocity Profile Measurement of a Moving Body by Microwave Interferometry,” IEEE Trans. Instrum. Meas., vol. 39, no. 4, pp. 632636, Aug. 1990. [3] Seoktae Kim and Cam Nguyen, “On the Development of a Multifunction Millimeter-Wave Sensor for Displacement Sensing and Low-velocity Measurement,” IEEE Trans. Microwave Theory Tech., vol. 52, no. 6, pp. 1503-1512, Nov. 2004. [4] Seoktae Kim and Cam Nguyen, “A Displacement Measurement Technique Using Millimeter Wave Interferometry,” IEEE Trans. Microwave Theory Tech., vol. 51, no. 6, pp. 1724 -1728, June 2003.
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9/15/2010
A Novel Approach to a Multiband Transverter Design Jeff Kruth WA3ZKR Presented to the MUD 2010 Conference
Why a new transverter design? Are not the old ones good enough? • Yes, but our nature is to experiment! • New system level components offer greater flexibility (synthesizers!) • Multiband operation is costly, yet desirable (Rovers, etc)! • Some still like to homebrew….
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Basis for Conventional Single Band TransverterApproach • All communications is about filtering & noise i rejection. j ti • Single band approaches minimize filter design/implementation difficulties. • Clever use of hairpin/pipecap filter designs on FR-4 boards meet all requirement in a single band design. • Can require significant real estate.
Local Oscillators: Problematic! • LO is key component, used to be difficult, simpler i l with ith “b “building ildi bl blocks”. k ” • Single LO Frequency – Easy to do w/ surplus PLO or Custom XO/Multiplier. • Each band required a solution for the LO issue many times not trivial to meet issue, stability desired, etc.
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Conventional RF Approach • Basic RF Converter. • No Amplifiers, therefore Bi-directional Bi directional in signal path. • Filters usually considered a necessity in RF & IF path for noise & image rejection. RF Filter
IF Filter
Narrowband Mixer & Associated LO
Typical M/W Amateur Transverter • Features added for utility: – IF Attenuator – T/R Amplifiers – IF Filter usually not needed, IF radio suffices – Can remote LNA/PA, add line amp
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9/15/2010
Multi-Band Approaches • Desirable to cover at least 2.3-10.368 GHz in one box (4 bands) bands). • Potential for significant size reduction. • Front ends could be in box or remoted up tower. • Use modern technologies to solve old problem! • Cost savings is a possibility. • Drawbacks include – Higher complexity – Single point failure, all bands off the air!
Multiband Issues • Broadband mixer required, many types available 2-18 GHz, 1-15 Ghz, etc. • Need Multiple LO’s LO’s, multipole switch switch. • Multipole switch and multiple filters needed for RF side. • Can be built up over time, but bulky, and LO’s may not be lockable to common reference.
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9/15/2010
Multi-band LO Requirements • Previously a severe constraint! • Prior schemes involved either PLO bricks or crystal multiplier schemes with different multiplication ratios. • Availability of modern frequency agile synthesizers can change this! • Currently L band .9-2 Ghz in sub-bands.
Multiband Design Improvements • Use a synthesizer locked to a reference f stability for t bilit issues. i • Use multipliers from old PLO blocks for LO multipliers for ease of implementation. • Use a single electronically tunable filter for all band RF image reject task. task • Integrate a broadband amp and reversing switch for RF driver/line loss comp.
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9/15/2010
Multi-band Block Diagram • • • • •
Simple! LO’ can b LO’s be added dd d llater t YIG filter is fixed tuned SMA n-pole relays, cheap WJ, RHG, Add. Labs Anzac M/A-COM Mxrs Anzac, • Multiplier Sections from old broken PLO’s
What’s this YIG filter thing? • YIG tuned filters (YTF’s) key to M/W wideband receiver systems systems. • Provide stable, easily tuned passband over multi-octave range. • Made by wide variety of vendors! • Real cheap at hamfests ($10-$100), if thrifty shopper! (I found 3 at M/W update) • Need a “special” DC driver circuit? Not really!
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9/15/2010
More on YTF’s • YIG material provides a magnetically tunable resonance at M/W frequencies. frequencies • Magnetic field created by electromagnet in form of solenoidal pair. • Current sets field hence frequency, so current source should be clean (low noise as possible) and stable (low DC drift). • YIG sphere kept stable by small 24 VDC heater (150 mA)-not always needed. • YIG magnet current typical 0-1A or less.
YTF’s, All Shapes & Sizes! • • • • • •
Made by lots of folks for the last 50 years! Inside of all kinds of old M/W stuff! HP 8445A preselectors HP 8441 preselectors AILTech 707 SA RF Black boxes…
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9/15/2010
Typical YTF Response • YTF circuits inherently broadband. • Yigs marked as octave typically broader • Example is YTF used as 4-8 GHz, found to be 2-18 GHz.
Powering Up Your YIG! • Many hams shy away as these seem too exotic. ti • Driver circuit seems to be a stumbling block. • Driver design sought that was very simple yet worked well well. • Decided on a cheap power OP amp!
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9/15/2010
YIG Driver Schematic • Very simple circuit, needs good heatsink! • Part is L165 5 terminal power op-amp. • 5 watt low ohm stable R needed. • Bi-polar supply, neg. is low current, DC-DC conv.
Datasheet for L165 • Really nice power op-amp! • Capable of 3 Amps! • Less than 1A needed for us! • Made by ST Microelectronics.
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9/15/2010
Breadboard YIG Driver • Obviously non-critical construction! • Key K was heatsinking h t i ki both device and power resistor! • Current can be sourced by either polarity supply by inverting drive voltage polarity.
Test Setup to Test Driver • Simple to align, tune for peak output. • Use power meter or crystal detector. • DC voltage tuning approx. 0-3 V.
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9/15/2010
Filter Responses 2.3 & 3.45 GHz • Simple, stable, easy to get filter shape!
Filter Responses 5.7 & 10.4 GHz • Typical bandpass, approx 30 MHz wide
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9/15/2010
Converted Multipliers • Bricks are cheap, esp. broken ones! • Multipliers are simple, really don’t fail much. • Old brick PLO is what dies. • Simple to excise mult. • Add SMA connector.
Performance of Multipliers • Variety of bad bricks in Junque box. • 3.3 & 5.6 were easy! Low drive requirements, high output power. • 10 GHz from White box LO! (At last, its good for something…) • +21 dBm drives from 1 GHz surplus amps.
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9/15/2010
Power In/Out for Multipliers • 3312 MHz - +7 to +13 dBm out, 1104 in@ 15 20 dB 15-20 dBm. • 2 types for 5616 MHz: x4 & x5, x4 gave 9.5 dBm out for +20 in @ 1404, x5 gave +12 out for 1123.2 @+20 dBm. • White box converted mult mult. X6 X6, gave 10224 MHz @12.5 dBm for 1704 Mhz @20 dBm. • No 2160 MHz Doubler tested, DBM?
The Guts of a 4 Bander • • • •
Spread out on bench approx. 14 “ square Will pack up much smaller. Key is A32 synth. Can add multipliers as you develop them! • Lock to a Rube? XO?
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9/15/2010
Final Thoughts! • Presented to provoke experimentation with new (to us) approach. approach • 2nd YTF could be used with untuned SRD Multiplier to make tunable LO as well. • System would make a nice Noise Figure Meter front end for conferences….. • Has p potential to educate and p provide utility! y • I recognize that this will not supplant traditional transverter approaches, merely complement them.
Questions?
• & Thank You for listening!
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A YIG Filter Primer & Simple Driver Circuit for HAM Projects Jeff Kruth, WA3ZKR I have always been fascinated by YIG tuned microwave components for many reasons. One of the foremost is that they revolutionized RF test equipment, allowing broadband sweep generators and spectrum analyzers, without the need for the bulky and problematic high voltage power supplies needed for backward wave oscillator tubes (1). Since YIG frequency changes are linear with current, the need for breakpoint linearizers, required in BWO and varactor circuits, was eliminated. This simplified the drive circuits and made the frequency scales linear with ease. Another reason is that they made airborne electronic warfare wideband receiver systems smaller, cheaper and very flexible, and this was another area of my interest, both professional and hobby. YIG tuned filters (YTF) and oscillators (YTO) are simple devices, using the fact that YIG (yttrium-irongarnet, a ferrite) material, if properly made and shaped, will exhibit a low loss microwave resonance when magnetically biased. This resonance frequency can be tuned by varying a magnetic field imposed on the YIG material, which is usually shaped in the form of a sphere, although rods and thin film sheets have been used on occasion for special purposes. The unloaded Q of the resonators can be quite high, in the 5000 to 8000 range, resulting in narrow band tunable responses. The bandpass remains narrow even when loaded by microwave coupling loops attached to the real world. The magnetic field is developed by a solenoidal electromagnet whose field is at right angles to the coupling loops. The current needed to tune a device over an octave or better is usually less than 1 ampere maximum, and sometimes quite a bit less. These resonators can be used as elements of a filter or in the feedback circuit of a semiconductor oscillator. These oscillators typically use transistors (both bipolar and FET, although FET’s have been replaced by bipolars as the phase noise is better (2)). In the past, at frequencies above 8 GHz, Gunn diodes were sometimes used, but these had their own problems, and are not used very much anymore, except at millimeter wave frequencies. Ham use of YIG oscillators and filters is usually limited to what is built into their commercial bench test equipment. However, a few hardy souls have made their own sweepers and spectrum analyzers using these devices (See the 1994 Proceeding of the Microwave Update Conference for some examples). I also did this in the early days, before I had built up my test bench. One project was to substitute a YIG tuned oscillator for the 2-4 GHz BWO in the early HP8551-851 spectrum analyzer, a very rewarding project (3) at the time. YIG devices are ridiculously easy to employ from a standpoint of the RF parts end, but many shun their use. This is because they do not understand how easy YIGs are to use, and they do not have a ready solution for the driver circuit that controls the current in the field coil. The goal of this paper is to encourage experimentation in the ham community with these useful devices by making the analog driver circuit easy to implement. One project I had long thought of which would benefit from YIG technology is a multiband ham microwave transverter for 2.3 through 10.3 GHz. This was based on my knowledge of wideband receiver systems and how YIGs are used in them. When I attended the 2009 SVHF Conference I heard several talks in which the authors presented ideas for a multi-band transverter. One issue, then as always, is the need for multiple filters for LO & RF portions of the transverter, and this was part of the discussion at these presentations. Naturally, it proves non-trivial to implement highly selective filter/amplifier chains for a multiband design. It was natural for me to think of a YIG filter for this
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portion of the application. I did not consider a YIG oscillator for the LO as it would have to cover 2.1610.224 GHz, and while these wideband devices do exist, they are harder to find, the typical octave band devices being more common. In addition, a synthesizer loop would be needed to lock the LO up, and then there would be lots of discussion on phase noise performance, size and weight, etc. However, YIG filters are relatively abundant (I bought three for 10.00 each at Microwave Update in Dallas in 2009), can be broadband and still very selective, and are easy to use. For the LO, I have several thoughts based on the A32 LO synthesizer for this purpose and have bought several from Down East MW to learn with. The actual multiband transverter implementation is the subject of another paper. Another interesting application is a broadband panoramic receiver, made by using a YIG filter hooked to a crystal detector! Combined with the appropriate driver, sweep circuit, an old low frequency oscilloscope and a little time, a useful broadband spectrum analyzer can be made with approximately -45 dBm sensitivity and multi-octave-in-one-sweep frequency coverage! Many companies over the years have built and offered such products, which are very useful for harmonic testing, etc. Testing YIG Filters I measure the YIG filters I get my hands on in a setup that includes a laboratory grade YIG current driver box, and a scalar network analyzer covering 2-20 GHz. I usually generate a plot of frequency coverage and current requirements to tune the device. A typical device plot and data table is shown as Figure 1. It is interesting to note that almost all YIG devices work far outside their stated bandpasses. This is true for oscillators as well as filters. I have had filters marked 3.7-8.2 GHz tune from 3.3 to 18.6 GHz, and 2-4 GHz filters tune from 2-12.4 GHz or higher! So often, those junk box items are useful beyond their marked range.
.
Figure 1. Typical plot of YIG Filter Bandpass & Current
A YIG filter is a simple device as far as DC connections go, usually having only four terminals, two for the main coil, easily identified by using an ohm-meter and measuring for the low resistance value (< 25 Ω) across the appropriate pair of terminals). The other pair of terminals is connected to a positive
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temperature co-efficient (PTC) thermistor that is used as the YIG sphere heater. Controlling/stabilizing the temperature of the tiny YIG ball to the correct value generally provides for the lowest insertion loss across the operating range. This voltage is usually 24-28 VDC at 150 mA or less at steady state. A small current spike is observed at turn on, rapidly decreasing to the steady state value, so the heater supply must accommodate this. Years of experience has shown polarity is not critical, although if marked, you might as well conform. I have also run these devices without using the heater, and have generally found little or no change in performance, but also recognize that for these devices to perform well in mil-spec temperature range environments that the heater is probably needed (good for rovers to know…). My test setup offers considerable ease in test, but YIG devices can be tested at home, without an elaborate setup. What is needed is a tunable signal source covering the frequency range of interest, a device to detect the RF (a crystal detector or power meter is OK, but a spectrum analyzer is nice…) and a stable DC power supply capable of supplying up to 1A or so, with a series resistor (such as a 5-10 Ω, 5 W type). Your testing will take a little more time, but is very simple: you wish to “find” the current that gives the minimum insertion loss at the frequency of interest. If, for example, you wished to use the filter on the RF side of the system at 13 cm, you might set the generator to 2304 MHz, verifying with your detection system that you have sufficient RF amplitude to cause a noticeable response, then, insert the filter between the generator and detector. Adjusting the current (by either adjusting voltage or current depending on your supply) carefully from 0 to 1 A you should see a peak in RF output power. If a crystal detector is used with an oscilloscope, the generator could be amplitude modulated (1 KHz is typical, usually a feature on most generators) and the AM waveform peaked up on the scope. The current for this setting is noted (a digital ammeter in line is nice…), and the process continued until the bounds of the filter are found. The Driver Circuit To use the filter, I went to my file of YIG driver circuits and looked for a reasonably modern, relatively simple driver approach that would also be of sufficient performance to be stable enough to make the rest of the electronics simple (4,5). I discarded many designs, including an earlier one of my own (6) and finally went about rolling my own based on a power op-amp device made by ST Microelectronics, called the L165 (7). While not a recent part, this device is newer than some of the discrete implementations I am familiar with. Additionally, it makes a functional design that met my goals and did not require any exceptional effort or creative genius on my part, which is good! It did require some attention to thermal stability issues, as I did not want the circuit to “drift” as it warmed up, detuning the filter off the frequency of interest. The input voltage was roughly 0-2.5 volts, so the output current was negative, so the negative supply was the more heavily loaded. This is not consistent with most ham designs, where minus voltage supplies are usually capable of only modest current sinking. Usually, there is plenty of current available from the +12 VDC supply, as in mobile applications. So, if a negative polarity input voltage is used, the positive supply to the op amp will be the more heavily loaded, supplying the YIG coil current. If a positive drive voltage is desired, based on other considerations, then an inverting amp may be used before the power op-amp. This would also allow for scaling and offsetting, if required. A small DC-DC converter could be used to supply the negative rail. It might be possible to work up a single supply design, but this requires more skill and several tricks, so I stuck to basics. A note on the datasheet for this part: There is an error in Figure 2 of the L165 data sheet, the basic circuit of my driver, and that is that the pin numbers for the non-inverting and inverting inputs are switched. The circuit drawing is correct in that the input is to the inverting pin, but it should be labeled “2” not “1”.
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The basic circuit is presented in Figure 2. The layout for the circuit is non-critical. I hand-cut a circuit board out of a scrap of FR-4 (G-10) material for quick mounting of the parts for the test needed to write this paper. The L165 comes in a 5 leaded TO-220 outline package called a “Pentawatt Package”, which I assume means 5 watts continuous dissipation. The leads are staggered, making hookup a bit tough, but I used a pair of needle-nose pliers to flatten and reform them to a single plane in order to simplify my breadboarding. It is important to use high quality components for the driver circuit, such as 1% metal film resistors, in order to minimize any drift. It is also important to heat sink the L165 power amplifier IC adequately to prevent thermal drift in this device as well. Wire leads could even be attached to the device in order to ease the mounting/heatsinking requirements. The tab is not at ground potential so the tab must be either isolated from the heatsink, or the heatsink must “float”. It is also convenient to mount the high power feedback resistor on the same heatsink. I used one of the gold anodized “Dale” types, as I have these. Other types could be used as well as long as they are thermally stable types and can handle the power. I used rather large tantalum caps for the bypass function on the + & - power supply legs, a smaller value would suffice. Not indicated on the diagram is the power supply voltages (plus & minus 12 volts), and the input is the left-most 10K resistor. The “snubber” circuit on the op-amp output, consisting of a .22uF film cap and a 10 Ω resistor, is recommended by the manufacturer of the op-amp, in order to increase stability of the amplifier when driving inductive loads, such as a YIG main tuning coil.
Figure 2. YIG Driver Circuit using L165 Figure 3 shows a picture of the bench test lash-up. The filter chosen for the tests was a YIG-TEK 183 series filter (whose data sheet is shown as Figure 1). These are broadband 2-18 GHz designs and are found in old spectrum analyzers like the AILTECH 707-727-757 series. They are also found in the HP 8445 preselector for the 141-8555-8552 analyzer system. I chose this device purposely as the tuning
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coil current is less than 500 mA at the maximum value. Higher current can be supplied from the L165 device, up to 3 amps, but I wanted to keep the heat dissipation and heat sink size smaller for this test. This device performed well. Initially, the bandpass showed a bit of drift as the circuit warmed up, but this was my fault, as I was in a hurry to see it work, and did not use enough heatsink. This drift was greatly reduced, really virtually eliminated, by using a larger heatsink. Devices from other manufacturers could also be used from vendors such as Ferretec, Trak, Watkins Johnson, Avantek, Varian and others, with good results. The old preselector for the HP 8551/851, called a 8441, has a nice WJ YTF which covers 1.7-12.4 GHz.
Figure 3. Test Setup w/Driver & YIG Connected to Scalar Analyzer Figures 4a-d are the swept bandpasses at the four RF frequencies of interest, which are 2304, 3456, 5760 and 10368 MHz. Notice the rejection for low inject LO frequencies for 144 MHz IF (2160, 3312, 5616 and 10224 MHz respectively). There would be no difficulty whatsoever with image and LO rejection! The bandpass of the filter is observed to be approximately 30 to 40 MHz across this range. The 3 dB down point and the pass band in between shows good symmetry and is relatively well behaved. The upper slope of the pass band shows the typical “bumpiness” associated with the usual spurious resonances associated with YIG devices. This is of no importance to our needs, and is simply mentioned to explain the non-symmetry of the pass band shape. This particular filter shows a small “double-hump” response at 5760 MHz, not common, but considered no difficulty for the project. The shape and selectivity of this filter is very good for our uses.
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Figure 4a. Passband at 2304 MHz
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Figure 4b. Passband at 3456 MHz
Figure 4c. Passband at 5760 MHz
Figure 4d. Passband at 10368 MHz
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In conclusion, YIG tuned components provide the opportunity to make multiband systems for amateur radio and test bench use. The ability to realize all the filters required for a multiband transverter by using one or two YTF’s and simply changing a voltage is quite interesting and should be explored by the innovators among us. Surplus store, hamfests and eBay yield a surprising number of these devices at low cost, if looked for. Best thing is, the filter engineering has been done for you, and they are simple to use as well. 1. 2. 3. 4. 5. 6. 7.
References “Magnetically Tunable Microwave Filters Using Single Crystal Yittrium Iron Garnet Resonators”, P. Carter, Microwave Theory and Transactions, IEEE Press, May 1961 “Low Noise Bipolars Silence Noise in 18 GHz YIG Source” Microwaves & RF Magazine, November 1988 “HP 8551B YIG Conversion”, J. Kruth, 1991, self published “Design a Stable Current Source for YIG Filters”, B. Taher, Microwaves & RF Magazine, February 1988 “YIG Drivers” Application Note 99-002, Micro Lambda Inc. “HP8551 YIG Driver Circuit”, J. Kruth, Proceeding of the 1994 MUD Conference Datasheet, L165 3A Power Operational Amplifier, ST Microelectronics, July, 2003
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LO Phase Noise effects on MDS Gary Lauterbach AD6FP
How could LO phase noise effect MDS? • MDS is determined by Signal/Noise ratio – Only three scenarios are possible
• Noise floor increase:
– In the presence of strong interfering signals – With only a single weak signal
• Signal level decrease
– Spreading of signal energy beyond discernable bandwidth
• Both: signal decrease and noise increase
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History of amateur LO phase noise MDS effects • MUD 1996,1997 W8MQW, WA6KBL
– Noise floor increases – Theory and negative confirmation with measurements
• MUD 2008 W1GHZ
– Observations on field MDS tests, no theory of signal or noise effects
• MUD 2008 K0CQ
– Noise floor increase – Theory with no experimental data
• MUD 2004,2009 WA1ZMS
– Signal decrease due to spreading – 2004: Low BW sub-mmw needs low phase noise – 2009: Experimental “confirmation” of W1GHZ observations
What is LO phase Noise? • Two views: Spectral and Temporal
– LO energy spread over spectrum surrounding the LO center frequency – Time jitter of LO waveform zero crossing
• Both views are valid and measurements can be translated between them • Can be both deterministic and random • Modulates the LO: AM and FM – FM phase noise creates no additional LO energy
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Reproducing WA1ZMS results • Brian well documented his experimental setup – But no phase noise plots were included
• Random noise FM modulating a laboratory signal generator – Brian used:
• Homemade noise source • HP 8640a signal generator
– I wound up using:
• HP 3561a random noise source • HP 8662a signal generator
– 8640a is not sufficiently stable for very close-in phase noise measurements
Brians measured spectrum • FM noise modulation producing 2db MDS degradation
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My measured spectrum of WA1ZMS -2db MDS experiment • 8662a @ 144 MHz FM modulated with random noise
Phase Noise Measurement • Pair of HP 8662a signal generators
– First 8662a is EFC locked through a 0.1 Hz BW PLL to the DUT for PN measurements • Switchable 40 db gain baseband LNA
– Second 8662a is a noise modulated source
• • • •
HP 70210a Spectrum analyzer HP 3561a random noise source KE5FX USB baseband digitizer KE5FX TimeLab measurement software
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WA1ZMS -2db MDS phase noise plot • Note the 20db/decade phase noise increase – Unlike any real world LO – F^-2 over entire PN range of interest
• Integrated power over 1-100 Hz is a significant % of LO total power
Here’s the visible MDS effect • SDR-IQ 10 MHz IF of 154 MHz signal and 144 MHz LO: – Left: clean LO – Right: -52dbc PN @ 1 KHz WA1ZMS noisy LO
• Signal spreading causes S/N decrease of >1.5 db in 27 Hz BW • Noise floor didn’t go up
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Why 1 KHz offset PN is a bad metric • 1 KHz offset PN is not a predictor of sub 100 Hz PN • Sub 100 Hz offset PN effects “purity” of narrow band weak signals – CW: 30 Hz “ear” BW,