radio

CQ CQ CQ de wa4chq wa4chq wa4chq/qrp k
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"If Stevie Ray Vaughan was a ham, he'd be pounding brass on a homebrew, qrp transceiver..."

I have been doing the qrp "thang" since late November, 1994. At that time, I would "throttle back" my FT-101ee to around five watts or so. Prior to that, most of my cw operating was between 30 and 100 watts. I have always been intrigued with home built radios, but was a little intimidated with schematics and parts procurement. In the back of my mind I kept seeing the article written by W7ZOI and K7TAU about "The Mountaineer-an Ultraportable CW Station". It was in an August 1972 issue of QST. Boy did I want to do something like that. But I wasn't ready.
Then one day, I took the soldering gun by the cool end and started to build. My first attempts were crude. The layout was messy and the hookup was sometimes a tangled mess. But it was a start into a very fascinating part of ham radio, very much like what I can only imagine the early days of wireless were like. With each project, I became more comfortable with laying out the parts, etching pc boards, getting parts, winding coils etc. What was really fascinating was I was learning about radio and was starting to use some of the theory I had memorized for upgrading to Advanced and Extra Class Hamster. Right now, I have qrp rigs for 40m, 30m and 20m--all from different designers, as well as homebrew test equipment for putting together my flea powered radios. My antenna is just a 33 foot piece of metal, set vertically and matched by a tuner. I would like to have a better radiator, but this is all I can manage where I live. I don't work much dx, but that's fine, I never did much of that chase anyway...I just enjoy making a contact with my own stuff!!

chief operator, wa4chq/qrp tuning in a fellow, brass pounding, low power hamster

Quick Index

Pride and Joy
	My 30m DC XCVR
20m Superhet XCVR
	Some old projects
Homebrew test gear
	Inside the rigs
A few cool links
	DixiePixie
Latest project (7/2000)
	Hellschreiber
Latest project (3/2001)

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My favorite homebrew rig is my 40m transceiver. I found the schematic in a back issue of QST and thought it would be a challenge to build. The fellow that designed it is NN1G. I had read many comments about it in various qrp publications and it seemed like most of the folks that had built one really thought it had an excellent receiver and a very stable vfo. I got most of the parts for it from Dans Small Parts. I built the receiver first, using double sided copper clad board---the top acting as a ground and the bottom I had cut soldering islands with a exacto knife. Parts that weren't grounded, I drilled and countersunk the top and soldered to the pad on the bottom. Other than a few minor wiring mistakes, the receiver worked the first time, and was spot on frequency! I built the transmitter on another board, in the same manner as the receiver. It worked the first time also. I made a few mods to suit my needs, and added a Tick-1 keyer chip inside the xcvr cabinet to give me the option to use a keyer during contests.

40m superhet
xcvr (Pride and Joy)

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The next rig in the family is my 30m dc transceiver. It is truly the "Heinz 57" of the three. The rx portion is from a Doug DeMaw design which I modified and the vfo is based on a Wes Hayward concept. I made the vfo for 5.05 mhz and used a doubler to get it up to 10.1 mhz. The transmitter is from many sources. The board were made in the same fashion as the 40m rig. Output is about 1.25 watts and it is housed in a larger cabinet than the 40m rig. The receiver works well (after some troubleshooting) and I have made many contacts with it. It draws more current than the 40m rig, and I don't think I'd use it in the field. There are very many parts in this rig....

30m direct conversion
xcvr

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The last rig is one designed by w6emt- the nw 80/20. I chose 20m and only built the receiver portion. This was a pretty hefty project, although the 30m DC rig was pretty major too! Layout was the same as the others except this time I etched the islands. That was my first attempt at that process. I am happy to say that I am a lot better at it than at the time of this project! The radio worked OK but as usual, there was some tweaking needed in order for to work right. There is quite a loud hiss in the audio which according to some of the crew on the qrp-l, is caused by my 386 chip. I tried everything that I had read concerning the hiss problem for that particular device, but nothing seemed to work like I had hoped. Replacing with a quieter chip is the answer. The transmitter is the basic vxo circuit- power about 1 watt. I have made about 10 qso's and most of those were during a contest. In all honesty, 20m has never been a favorite with me, so I haven't really spent the time getting this rig to in a-1 shape. My 40m rig has spoiled me, and I kind of hoped everything worked like it! I think if I do anything, it will be to finish the transmitter section like it was meant to be, and not be rock bound as I am now...

Revised 11th September, 2000. Please clickHERE to see pictures of my "downsizing".

20m superhet
trans-rcvr

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Here is what I have been messing with lately....

This is a 40m vxo that I am bread boarding. I really don't need anything like this but its just fun knocking things together. Output is about 1 watt and the xtal swing is about 4 khz. I may build a vfo and delete the xtal and then build another receiver for 40m. to go with it. Hey, that's what it's all about!! The first time I built a little oscillator like this, was back in 1996. In fact, my real building career started from a simple circuit like this....and yes you can have many qso's with 1 watt.

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40m vxo-revised

I decided to change the vxo around a bit. I wasn't really happy with the design. I added a couple of chokes in series and a capacitor in parallel to give more swing to the xtal. I now get about 8 khz. swing. Also added a keying switch. This now is more like the early vxo transmitters I built when I first got started. None of the schematics are my designs---they are made up from many plans I got from various publications. I still haven't decided what I am going to do with it....maybe a qrp rig for hiking or camping.....

Revised again

I tried hooking up the audio portion of the Pixie2 to the above circuit. I bypassed the keying switch and brought the voltage in as before with the vxo #1. I was able to copy some cw with it but it wasn't very loud. I tried different things and just couldn't get it to do what I wanted. That's when I got the junk box out and got the parts together for the Pixie2. I found a few articles about it and decided to customize the original design. The result is what I call the Dixie Pixie. Power out is about 200mw and xtal swing is about 5 khz. I have not tried working anybody with it yet, and since I am still experimenting with it, have not made a proper pc for it, nor have I put it in a proper cabinet.

Well, I decided to go back to the original Pixie2 design, with a few mods that I had found on the Internet. I still have not tried working anyone with it. Power out is pretty low and it would be a real challenge for me to work someone with the antenna set-up here on the Island. Below is the schematic and some photos...sorry I can't get better detail with my pictures.

I don't show it in the schematics above, but originally I used 2n2222's. Power out was pretty low. I tried replacing the "final" with other transistors I had used in other oscillators but that didn't improve things much. Then either I read about it or I just did it, but I replaced both of them with 3904's and what a difference it made. After that I cleaned the layout up and rebuilt it "free-style" (ugly sounds ugly and I like 'em to look good) and placed it in a small mint tin.

Well it has been revised again! But the best thing is I finally worked a few hams with the Dixie Pixie. On May 23, 2000 running 400mW, I worked W1PID. Then on May 25, 2000 running 250mW, I worked K1QM and again, W1PID. I still have not got the offset to my liking, but rubbering the xtal during rx helped. Also, I am still getting bleed thru from SW broadcast stations. This has been a fun project. One thing to note is my Dixie Pixie is based on several Pixie's I have seen in various publications. I am having fun trying a little of this and a little of that from other designs. That is the beauty of homebrewing!

One thing I forgot to mention was that with 9v I get 250 mW and with 12v I can get 450mW.

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July 16,2000---Latest project

I have

been wanting to build something here lately but because of other things going on, just didn't find the time. I order parts for building the SST-40, but was not able to get the xtal's. Since then, I made another order to Mouser and the rest of the parts should be here soon. In the mean time, we had a break in the weather and I couldn't get the "building bug" out of my head. So yesterday, after a week of reviewing designs from my reference library, I decided on a DC receiver for 40m. It is based on the Micromountaineer from the April 2000 issue of QST (w7zoi) except I built a vfo for it instead of being rockbound. The vfo design uses diodes for tuning in place of the variable cap.

The design is based on things I found in Demaw's W1FB's QRP and Design Notebooks. The front end (I think that is what you call it) is from a design from Monty, N5FC. Look at his little receiver on his web page. I had all of the parts needed in my junk box and even had the torroids already made up from a past project. After a few "hot" parts, causing a zener to fry, I started to receive some honest to goodness ham radio stuff.... Tuning is still pretty sensitive, but hopefully will be able to clear that up and maybe make up a nice etched board for it. Right now, it is pretty ugly looking. Sorry about the quality of the pictures. They aren't the greatest but at least you get the "picture". The schematic is down below.

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At my work bench, I use a Micronta FET VOM, a Weller SP-23 soldering gun with a homebrew heat output adjustment and an Autek RF Analyst. I also have a homebrew adjustable power supply. The remainder of the test gear I use is homebrew. I have a SWR-PWR meter, a Audio oscilator and a RF probe.