ah6gi/4
mini-DX-60.
This page is an overview of the miniature DX-60 project. This is a small working amateur radio transmitter capable of long range communications. This is the first public showing. Hooked up to a 2nd antenna, you should hear it HAMMER into the unmuted SB-303. The CW is clean, clear, chirp free, and REALLY LOUD. A couple years ago, I saw some full sized replica's of classic radios. These were made of wood with photo overlays of Yaesu SSB transceivers, 1920's AM radios, but had crystal diode receivers inside. The point was to make a working crystal radio and make it look like some other kind of radio. I thought about this for a few months and gradually the idea of a "scale model" DX-60 came up. I lost some time after I saw the wooden Yaesu due to several serious health problems, a failing employer, you know the story. I don't have the skills or patience to design and build one from scratch so I chose parts that were readily available. I looked for a small CW transmitter with TR switching and the ability to mute a boatanchor receiver. Finally a QRP'er pointed me at the PIXIE2. Gradually, I gathered the parts and worked out the concept. I wanted to build a working, model radio. Not necessarily a 100% accurate scale model, nor 100% fully functional. I wanted it to be immediately recognizable as a "baby" version of the real thing and to work as a radio. Transmit if a transmitter, receive if a receiver. Not necessarily as good as the real thing but close enough. I had the parts in hand for about a year before beginning construction I started with a PIXIE2 QRP transceiver kit from HSC. The PIXIE2 has a two stage crystal controlled CW transmitter and an amplified, direct conversion receiver that uses the transmitter's crystal oscillator. I wasn't interested in the PIXIE2's receiver and planned to use this as a transmitter only. The PIXIE2 in the pictures is fully functional as a transmitter. I left off the receiver parts. I have the 7.040 QRP calling frequency installed. I used a Radio Shack aluminum project box for the chassis. I bent the flanges down to form the folded case lid of the DX-60. I painted the cabinet with Rust-Oleum 1934-Meadow Green spray paint. I think it's a fair match for the DX-60 Heathkit green. I drilled the front panel for 3/32 submini phone jack. In the real DX-60, this is a 1/4 inch phone jack so this is a reasonable substitute. You can see that the key-jack stands out from the front panel. That's because it's real.
|
The Radio Shack aluminum box is a close match for the DX-60 dimensions, it's a little wider so I stretched the JPG of the front panel using The GIMP image editing program. I printed the image on a color inkjet printer on regular paper and "laminated" it with 3M packaging tape. This is a good trick for protecting paper. I applied the front panel overlay using rubber cement. Collins uses a similar technique for their S-line. The small rubber feet are tiny rubber bumpers from the hardware store. While I was there I got some stainless steel sheet metal screws. I'll use these to hold the cover on. The RF connection is a mini-UHF connector. This is good substitute for the standard UHF connector on the full size DX-60. At first I thought I'd just use a BNC or RCA but having mini-UHF connectors is just too cool. I could make all of small knobs real, for a keyer speed control, crystal switch, VXO. Lots of possibilities but I wanted to throw this out as an idea and maybe get some ideas from others too.Why a DX-60? It was my first transmitter. It's too cool to have this little guy again and actually be able to use it. I'm still fairly young -cough-cough-, mumble, 59, and still working. I expect that when I retire and scale back, I'll reduce my holdings to a modern basic transceiver, a 2 meter HT, and one nostalglia boatanchor, like an SB-303 and this toy transmitter. That means letting someone else enjoy the S-Line, the SB-104, and the Signal/One CX7A. Most "builders" will come up with much more finished and better performing radios than mine. I'm pretty good at thinking up stuff but poor at the execution. Future plans - The chassis has enough room for an AC power supply, a keyer, as well as a power amplifier. I'd like to increase the power to a couple watts of RF output. I also hope to install a power output meter. A fun project might be a scale model Collins 32S-3. WA6OTP sells a PTO kit. The trick is to figure out the mechanicals. One thing that might help are those printers that print labels for CD's. That might be a way to make the PTO scale. For receivers? I've been looking at small mechanical counters. These are all over hamfests and were used in VCR's and cassette recorders. I'm thinking R-390! I might not build a full working receiver but I might take one of those Chinese SWL portables and repackage it to look like a baby SX-88 or R-390. I would get rid of the digital tuning and convert it into a knob twister. I could also see building a 20 watt RF amplifier into a small 30S-1 styled cabinet. It would stand, maybe 10 inches high. At that size, a clever person might be able to use a small tube, a 6V6 maybe.
|
