QRP Homebrew Transmitter - photos by NV9Z
This is the sometimes amusing (although it certainly didn't seem amusing to me at the time!) tale of the extraordinary lengths a young Amateur Radio Operator will go to, trying to gain the acceptance of those guys who helped him get started in this great hobby of ours.
I must admit that I have always considered myself very fortunate, because the group of expert Hams who Elmered me didn't just teach the ins and outs of Amateur Radio. By their amazing examples of competency and proficiency, they also inspired me to be the best possible operator I could be. I desperately wanted to be like them, if only half as gifted and talented. "Coach" Don Havlicek N8DE was my 11th grade Algebra teacher and is probably the single-most instrumental person in getting me hooked on Ham Radio. He has somewhere in the neighborhood of 300 DXCC countries confirmed, and designs and builds some of the best full size mono-band HF Yagis on the planet. Even though I graduated from High School over 22 years ago, I have never been able to bring myself to calling him by his first name. Many years ago, he tired of me always calling him 'Mr. Havlicek' on the air and finally suggested that I simply call him "Coach." Coach Havlicek once told me "Anybody can speak into a microphone, but CW is an art form." (I'm with you on that one, Coach!) Then there was Joe McGuire N9JM (SK) of Cambridge City, Indiana. Joe could carry on a CW QSO at 40+ WPM while reading a Zane Grey western novel at the same time. The Whitewater Valley Amateur Radio Club in Richmond, Indiana has given Joe the ultimate tribute: N9JM is our Club call. And of course there was Bill Wulff W9AIW (SK), who in 1921 (my Dad was born in 1923, so that seemed like ancient history to me) became the first licensed Amateur Radio Operator in Fayette County, Indiana, as 9AIW. When I first got licensed in 1981, Bill was still operating the same beautifully-crafted, mahogany rack-mounted transmitter, receiver, power supply (which had a utility pole transformer with primary and secondary reversed - 110VAC in, 4200VAC out) and 1kW amp that he had hand built in the early 1930's. In fact, I noticed that most of my Elmers had home-brewed at least one piece of gear. I decided early on that if I was going to be like them, then some day I was going to have to build something too. Which brings me to the story of the 40M "Butt-Buster" QRP Transmitter….
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QRP Homebrew Transmitter - photos by NV9Z
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It was Christmas 1984, but the Holiday Season didn't seem very merry to me. I had just gotten home from Purdue University for semester break, but I wouldn't be going back after the Holidays. After five semesters of tuition, room and board, I was broke. I had tried to transfer to Indiana University East in Richmond, which was a commuter college and therefore much less expensive, but it was too late to register for the Spring semester. No more college education for me until the Fall semester, and maybe not at all. I was feeling pretty low. To cope, I did what I always did to manage stress (and still do to this very day). I put on the 'phones and worked CW. When I hear the Code, my troubles just fade away. Working CW has always been very relaxing for me. One afternoon, I happened to work a guy in PA on 40M. I was surprised to learn that he was running just one watt on a rig he had built inside a tuna can (does that rig ring any bells??). I had heard a little bit about QRP but this was my first real exposure, and I was intrigued. I decided this would be an excellent opportunity for me to finally build something and hopefully my Elmers would be impressed. I had been a Ham for 3 ½ years. It was high time to prove my worth. It looked like I would have ample time on my hands during the next few months to devote to rig building, but finding the MONEY to do it with would definitely pose a problem.
In those days, any Ham who was worth his salt had built some type of Heathkit. Like most Hams of the era, I received a catalog from Heathkit at regular intervals, and the new 85 edition had arrived just a few days earlier, although I hadn't looked it over yet. I checked the Amateur Radio section and was thrilled to find a brand new QRP kit, the now classic HW-9 (WARC bands included!). There was a problem though. Even by early 80's standards, Heathkit stuff was pricy. I just didn't have the money to buy the kit. And I would probably need the matching power supply kit as well. When funds are required, there is no better source of financial capital than Mom and Dad. Perhaps my folks would foot the bill, and besides, Christmas was just a couple weeks away. I casually mentioned it to Mom (Donna, N9LQN - she wasn't licensed in those days). Boy, did that go over like a lead balloon! Mom let me know, in no uncertain terms, that her Christmas shopping was done. Then she demanded to know what was wrong with that other radio they had bought for me (a Kenwood TS-830S with matching AT-230 tuner). Before I could reassure her that the Kenwood worked fine, and I merely thought it might be fun to build my own piece of radio equipment, she took off on this wild tangent. She started testifying to anyone and everyone within earshot about how she and my Dad had shelled out $500.00 of his hard-earned money for a radio that suddenly wasn't good enough for me any more. And how she hadn't been able to watch an entire TV program since they bought the blasted thing for me. And how it was a wonder our neighbors hadn't already run us out of town on a rail, because she knew good and well that I had to be tearing up their TV's just as much as I did ours, and on and on and on. She was still ranting as I walked, tail-tucked, back to my radio desk. I conceded the fact there would be no HW-9 in my immediate future.
I was talking to one of the local Hams on 2 meters a few days later, lamenting about how badly I wanted to build a QRP rig but just couldn't come up with the cash, when Chuck Larson W9JWH (SK) jumped in and offered to "fix me up." Chuck promised he could provide all the radio components I could haul, let alone need to build a simple little QRP rig. I signed off 2 meters and was out the door and on the way to Chuck's house in a flash.
Chuck Larson was one of the most knowledgeable fellows I have ever met when it came to radio and electronics. This was a guy who actually replaced the Cyclotron when his wife's Amana "Radar Range" (a huge contraption that you young Whipper-Snappers nowadays call a microwave oven) went on the blink. When I got to his house, Chuck endowed me with a Sears-Roebuck washing machine carton that was chock-full of virtually any electronics component one could think of. He said the whole lot was mine, free of charge, as long as I didn't bring it back! He even threw in a partially completed 500W linear amplifier (it used a pair 811A's in the final stage) and all the stuff needed to build the B+ supply, but that is a topic for a future story.
I crammed all of this loot in the trunk of my 82 Ford Escort. There was so much stuff that I couldn't get the deck hatch closed and had to drive back home with it open. My Mom was less than thrilled as she watched me lug all of this stuff that she immediately classified as "junk" in the back door and down to the basement workshop. As soon as I got everything inside, I dove right in. I couldn't wait to see what all Chuck had donated to my QRP project. As I dug ever deeper into the depths of that flimsy old cardboard box, the more I could not believe what I was finding. That box contained a veritable treasure trove of vacuum tubes, sockets, crystals, volt and amp meters, air core resistors, variable capacitors the size of loaves of bread, electrolytic capacitors the size of Coke cans. You name it and I would almost guarantee you that it could be found in that box. And stashed all the way at the bottom, I found a stack of little magazines which I thought were TV Guides and Reader's Digests. Much to my surprise, they were QST and 73 Amateur Radio Today magazines from the late 60's and early 70's. I also found ARRL Handbooks from 1947, 1951 and 1968. There was no doubt, in my own mind at least, that this box contained the Mother Lode.
When my Dad, Robert N9LQO (he wasn't licensed in those days either) got home from work, I called him to the basement to show off my goodies. Dad had served in the Army Airways Communications System (AACS) during WWII and worked on 10kW aircraft homing transmitters in the China-Burma-India Theater of Operations (but that is a topic for yet another future story). I knew HE would appreciate this stuff. Instead, he took one look at the car battery-sized transformer for the amplifier power supply, snapped "You'll mess (not Dad's precise term but this story is rated E For Everyone) around and fry yourself with that (more expletives) thing!" and went back upstairs. Oh, ye of little faith!
I poured through those magazines and Handbooks for the next several days. Surely one of them would have a low power transmitter circuit that would be simple enough for me to tackle. I finally found an article on how to build a one-tube 40M QRP transmitter in a 1967 issue of 73. The rig used either a 6L6, 6J6 or 6AG7 tube, and used standard household line voltage (110VAC) for the plate. The circuitry looked fairly simple, even to an untested rookie builder like myself. I dug through my treasure chest, looking for components that I might be able to use. Much to my delight, I quickly found a metal 6AG7. I dug deeper and in virtually no time, I had found almost every component on the parts list, including a Simpson milliamp meter and a practically new filament transformer (110VAC primary/6VAC secondary). I even found a nice, barely used aluminum chassis to mount everything on. It looked like the only thing I was going to have buy at Radio Shack was four Zenier diodes for the bridge rectifier circuit. I made a "Shack Run" the next morning for diodes, and even splurged for 6 in. X 8 in. piece of "perf" board to mount everything on. My total investment: $1.73. Even my flat-broke bank account could afford that.
I spent the better part of the next several days in basement, working on the rig. I started with the chassis and hardware. I found a piece of .040 aluminum from some long forgotten project Dad had started years before. After about three hours of cutting with tin snips and filing with a rat-tail, (chassis punches?? I didn't need no stinking chassis punches!! I had never even heard of chassis punches!!) I had transformed that aluminum piece into a front panel, complete with a not quite-perfectly round hole for the milliamp meter, a ¼ in. mono jack for the key and a pair of variable tuning capacitors for the plate and tank. Soon, I had the transformer mounted, installed and wired with a section of old extension cord. A short while later, the tube and crystal sockets and SO-239 for the antenna were all in place. An old plastic pill bottle was reincarnated as a coil form. Winding the coil turned out to be a royal pain, but I struggled through it. The actual inductance was anybody's guess, but it would have to suffice. Chassis assembly completed. Everything had gone relatively smoothly thus far. Now it was time to start actually wiring the transmitter circuit. Little did I know that the road ahead but be a whole lot bumpier.
I started sorting the components for the transmitter circuit, but something seemed to be missing. I rechecked the parts list and everything was accounted for, but still something did not seem right. Then it dawned on me. I didn't have a circuit board. My only experience at building anything electronic, other than soldering PL-259's onto coax, was an AM/FM radio that I built from a kit in 8th grade Industrial Arts class. Many of the components came pre-mounted on the circuit board, and I only had to mount a handful more to finish it. But at least I had a neat printed circuit board to work on. Then I remembered the perf board that I had splurged for at Radio Shack. But it didn't have the circuit laid out for me on the bottom, and there wasn't any copper foil to solder to. How in the world was I ever going to put this transmitter together with no circuit board? I was totally perplexed. I bet Dad would know what to do. When I asked him, he glared at me over his evening paper as if I had just nominated Emperor Hirohito for President of the United States. "Circuit board?? What do you need a circuit board for?? We didn't have any (more expletives) circuit boards over in India! We were lucky to have spare parts most of the time!" Now I had done it. I was about to get the story of how a Japanese submarine torpedoed the supply ship in the Summer of '44, and Dad's AACS outfit was forced to go for an entire month with nothing to eat but macaroni and cheese, three meals a day, breakfast, lunch and dinner. I had only heard that story about a hundred times. Instead, he said "Just follow the schematic and solder the (still more expletives) leads together!" and then he went back to reading his paper. I snapped a crisp salute to the Technical Sergeant, did an about face and marched back downstairs at double-time cadence.
So, following the Tech Sarge's orders, I started soldering the lead from one part to the next. I got a few parts connected, but I just didn't like the way it looked. Then I had a brain-storm. Why not compromise and use the perf board too? I could stick the leads through the holes on top, solder them together according to the schematic on the bottom like Dad had said and nobody would ever know I hadn't taken hours to etch my own printed circuit board. I unsoldered the parts that I had already joined, and started over using the board. Everything worked great, at least for the first few components. I soon discovered that the leads on some of the larger components were too big to go through the holes on the board. No problem. I'll just drill out the necessary holes. A good plan except the smallest drill bit I could muster was a 3/16. A circuit board with holes that big would look utterly ridiculous and I would be the laughing stock of the entire Fayette County Amateur Radio community. I hated to admit it, but it looked as if Dad was right. I unsoldered everything AGAIN and started over AGAIN. It wasn't pretty, but the "Sky Wire" method seemed to work. I ended up cutting a small section off the perf board and used it to mount the Zeniers. It was the only way I could mount them in any configuration that even remotely resembled being square. Before I knew it, I was soldering the last two leads together. Construction was finished. But this battle was only half over. All of the hard work and expletives from Dad would be for not if the thing didn't transmit. It was time to find out if it would actually work.
I hooked an old 3.5-150 MHz SWR bridge up to the SO-239 and terminated the bridge with my dummy load. Then I plugged the rig into the AC outlet on the work bench. No mini mushroom cloud. So far, so good. I plugged my old straight key into the jack on the front panel, set the SWR bridge for 10W forward power, held my breath and cautiously closed the shorting switch on the key. Still no mushroom cloud, and the lights were still on in the house. And much to my amazement, the needle on the SWR bridge moved ever so slightly to the right. I opened the shorting switch and the needle fell back to zero. To be sure, I closed the key and Lo and Behold the needle moved back to the right again. The needle registered less than 1W on the 10W scale. There was no milliwatt scale for a precise RF measurement, but by my best estimate, I was getting about 350mW output!! I couldn't wait to get on the air with it. However, I soon encountered yet another bump in QRP Road.
I took my little gem of a transmitter upstairs to my combination bedroom/Ham Radio shack and quickly hooked the transmitter up to my B & W 40M trapped dipole (which incidentally is still up at my parents' home as this article is being written). Then it hit me like a bolt of lightning. That was the only antenna I had. How was I going to transmit on the QRP rig and still be able to use my TS-830 as a receiver? Oh sure, a coax switch would solve the problem, as if I had one, or even had the money to buy one. I had snatched failure right out of the jaws of success. That was the last straw. I threw up my hands in despair and declared the project a bust.
Later that evening, as we did almost every evening in those days, a bunch of the Connersville area Hams congregated on 146.520 simplex, to brag about the DX we had worked that day, gripe about the weather, and just plain enjoy the fellowship of Amateur Radio. I was telling Larry Clark KC9BQ (now WD9M) about my huge blunder with the antenna, feeling more stupidity and fatigue than sorrow, when another one of my Elmers, Walt Stevens KD9TO (now W9WS) came on 2 meters. Walt told me he had an idea that just might let me get that QRP rig on the air. At that point, I really didn't give a gray rat's behind whether I got on the air with the thing or not, but I had come this far, so why not give it one more shot?
Walt was the first Ham Operator I ever met. He lived just four doors up the street. We used to joke that we could probably work each other on our dummy loads. We offered a special "award" to any station that was able to work both of us: the often sought-after, rarely attained WASOBP (Worked All Stations On Boulevard Place) Award. Walt suggested that I call CQ on the QRP rig, and if anybody answered, he would QSP it to me over 2 meters. What a great idea! I quickly hooked my QRP rig up and sent a string of V's interlaced with an occasional T E S T so Walt could find me on 40 meters. He came on 52 and asked "Is this you on 7055?" and put the mic up to his brand new Kenwood TS-930 (solid state finals AND a built-in AUTOMATIC antenna tuner! - Great Scott! What will they think of next?). It was me all right but I was almost ashamed to admit it. Instead of the nice, crisp, clear CW note that I had grown so fond of, what I heard was the most irritatingly disgusting and downright sickening tone any CW devotee could ever imagine. Doodoodoooo Doodoodoooo, Doooo Doo Doodoodoo dooo. The thing was chirping like a love-struck sparrow!! I frantically tried to re-tune the plate and tank, but it was just no use. Jim King WD9EQU came on 2 meters and asked me what kind of birdseed I feed to that canary. Floyd "Pappy" Powell W9OZJ (SK) chimed in and suggested I feed it again, because it sounded like it was still hungry. Oh, the humanity! But just then, Walt said he thought someone was calling me. He put the mic up to the 930 again and sure enough, I heard KA9KWM (my former call) in the unmistakable "swing" of a bug. It was none other than Omer "Barney" Pea N9DNG (later NZ9H -SK) and man alive, that Vibroplex Presentation of his never sounded sweeter!
Barney (or "Gomer" as KC9BQ called him)
had been a US Navy Radioman during the Korean Conflict. He had
learned to send CW on a bug, and copy it on a manual typewriter.
And that was the ONLY way he could do it. He lugged that old
antique typewriter over to the Dayton HamVention one year and came
home with a 45 WPM endorsement certificate from the ARRL, but 15
WPM with pencil in hand seemed like a real challenge to him during
our Field Day activities. I quickly tapped out N9DNG de KA9KWM K.
Not only did Barney acknowledge me this time around, but he also
gave me a 599 signal report, despite that infernal chirp! My 350mW
had made it all the way to Barney's shack on Eastern Avenue, a
distance of six city blocks. KC9BQ came up on frequency too and I
worked him as well, although he was only 2 ½ blocks away. No
matter. I had made two QSOs on a rig that I had built with my own
hands. The date was December 21, 1984. The icing was put on the
cake Christmas Eve, when I went to the mailbox and found a QSL from
N9DNG. True to his form, Barney had completed the QSO information
using that old typewriter. The Holiday Season wasn't going to be so
bleak after all.
For my next project, I planned to build a little 40M "regen" receiver to go with the Butt-Buster, but like is so often the case, I never got around to it. I played with the Butt-Buster from time to time, but never could cure the chirping problem. Chuck W9JWH suggested I try to improve the over-all efficiency of the tank circuit by adding ceramic capacitors mounted in parallel with the tank variable tuning capacitor. Even after that modification, the thing still sounded like something that should be listed in the Audubon Society Field Guide of North American Songbirds. I never tried to make another contact with the Butt-Buster. The CW tone was just too embarrassing.
I must have been doing something right, though. Not long after that, I was invited to help teach the Code to a Novice class. Over the next three years, I assisted with several more classes, and taught the Code to quite a few very talented present-day CW Operators. I even managed to build a couple pieces of Heathkit test equipment along the way. Not only had I gained the acceptance and respect of my Elmers, I had become an Elmer myself.
The Butt-Buster remained with me through
the remainder of college, relocating to Richmond and beginning a
career in law enforcement, getting married, starting a family and
re-relocating to Cambridge City. In 1996, my brother-in-law Wayne
Klusman WA8KAZ was helping me tear down my station as we prepared
to move to once again. He was admiring the Butt-Buster and I
related some of the trials and tribulations I endured trying to
build the thing. I decided that the time had come for the bird to
leave the nest (pun intended) so I gave the Butt-Buster to Wayne.
Recently, he was cleaning his shack and decided the Butt-Buster's
proper place is with its creator. He returned it to me and
suggested that I keep it for nostalgia's sake. I'm going to do just
that.
By now, I suppose everyone's curiosity has been piqued as to how and why the Butt-Buster gained its moniker. After I had worked N9DNG and KC9BQ that evening, I unhooked the rig and set it over onto my bed. The gang stayed on 2 meters for a couple more hours. One by one, the guys signed out and I decided it was time to declare this triumphant day ended. But not before Fate was to rear its ugly head one final time on this project. I started to move the rig off of my bed, and in so doing, picked it up with my fingers under the chassis, precisely where I had tied in the negative lead on the 330uF electrolytic filtering capacitor. I must make a pretty good ground rod, because the cap discharged and shocked the living daylights out of me. I was literally knocked flat on my tail. Now it was MY turn to let a few expletives fly! I grabbed my VOM, set it to the 200VDC scale, put the electrodes across that cap and stared in horror as the needle banged hard against the peg, all the while Dad's "you'll fry yourself" warning was echoing in my cranial spaces. I switched to the 1000VDC scale and checked again. This time the needle registered about 350VDC. And that was AFTER it zapped me. I don't know how much charge that cap had BEFORE it bit me (probably not much more, and of course the current was probably no more than a few milliamps), but to me, it felt like about 3500 volts! Dad came back to the shack to see what the commotion was all about. When I told him what had happened, he just chuckled and said "You better cover the bottom of that chassis somehow or else that thing will bust your butt again one of these days." The name stuck. The next day, I found a piece of clear plexiglass from yet another one of Dad's unfinished projects. I mounted the plexiglass across the bottom of the chassis to shield the underneath components, especially that (expletives) filtering capacitor. After all, as it turns out, Dad is always right.
For every Elmer included in this article, there are least five others that I didn't get to mention. This article is as much a tribute to them as it is a story about me. Many are still active Hams, but far too many of them are now Silent Keys. Without their patience and enthusiasm, there never would have been an NV9Z, at least not one with MY name on the license. I dedicate this article to them all.
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Front Panel
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?? mH Coil on Pill Bottle Form
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6AG7 Tube and 7050 Khz Crystal
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Sky Wire Circuitry and Plexiglass Shield
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Chris Blaase, NV9Z was originally licensed in 1981 as KA9KWM. He operates almost exclusively QRP, and is working to attain both QRP-WAS and QRP-DXCC. Chris proudly serves as a Patrolman for the Hagerstown (Indiana) Police Department. In addition, he also serve as a Volunteer Firefighter/Emergency Medical Technician for the Hagerstown Volunteer Fire Department, and works as a part-time EMT for the local ambulance service. He lives with his wife, Julie, and two small children, Caleb and Abigail in Hagerstown.
NV9Z is ECI-QRP #009 and also belongs to the Whitewater Valley ARC, Richmond IN; QRP-ARCI #11172; QRP-L #2370; NW-QRP #347; NJ-QRP #383; HI-QRP #407; AR-QRP #280; NE-QRP #604; AK-QRP #576; NorCal; Knightlites.
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Copyright © 2004 Chris Blaase, NV9Z All
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