Hi Bill,
I was finally getting around to reading one of the recent SPRAT’s and saw a photo of your magnificent BITX17. Congratulations! A tip of the hat to Farhan for that very excellent design and it truly is a design that has traveled the world and made a radio available to many who otherwise would not be on the air.
It is a very robust design as I scratch built one in 2005 (or maybe 2006) and just for fun socketed every transistor so I could try various devices. I even had a bag of 2N706’s dating back to the late 1960’s. They all worked except for the carrier oscillator where I just couldn’t get enough swing in the oscillator to correctly place the CIO on the filter slope. That I attribute to the junction capacitance of the 2N706. By far the lowly 2N3904 that I bought for 4 cents each worked the best. Back when I built this I was W6JFR. Adding the EI9GQ frequency stabilizer really added a nice touch to the radio.
I should also tell you that when I built the radio my intent was to uses a piece of single sided copper vector board for the main chassis. It was the weekend and I didn’t realize the piece I had was not big enough for the project. So I took a piece of standard perf board and overlaid that on top of a piece of single sided copper PC board –AND hand drilled all of the holes – I went blind, cross-eyed and had a terrible hangover after consuming 6 beers in a short time span! See the photos below.
BTW I also built a 17M SSB transceiver using the bilateral amp stage from G4GXO as appeared in the SPRAT 128. That used a 4.9152 MHz IF and a 23 MHz Super VXO. In the case of the VXO I used 11.52 MHz crystals in the VXO and used a diode doubler to put the LO at 23 MHz. With the doubler –you get the bonus of 2X the frequency shift of the Super VXO. I also had made a custom set of crystals and used a small relay to switch those into the circuit and that essentially gave me almost the full SSB Band coverage. You can see that here
Also I have been using a simple bilateral stage consisting of a 2N3906 and 2N3904 and the results have been amazing. The latest work is a follow on to my shirt pocket transceiver and uses SMD components. See attached.
Here are some videos of the latest –which is now a two bander 40 and 20M. (Originally it was 75 and 40M)
https://www.youtube.com/watch?v=0UlBX7aznnM&list=UU4_ft4-oTdCMlWlL4XXHScg and https://www.youtube.com/watch?v=Wa5WiUZ9KoY
Have fun – this is such a wonderful hobby!
73’s
Pete N6QW
Congrats Pete! Beautiful craftsmanship. This looks like a Kenwood! I hope to eventually be able to get to this level in terms of complexity (probably never get there in terms of elegance of the build!), especially with adding displays to radios. 73, Bert WF7I
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