It was inspired by G8FWM - OM Brian L.Phillips' article, 'PW AVON - a 10W 2m FM Transmitter', in Practical Wireless (July - September 1978).
http://www.americanradiohistory.com/Archive-Practical/Wireless/70s/PW-1978-07.pdf
http://www.americanradiohistory.com/Archive-Practical/Wireless/70s/PW-1978-08.pdf
http://www.americanradiohistory.com/Archive-Practical/Wireless/70s/PW-1978-09.pdf
OM Brian's dedication to detail and his 1:1 PCB layouts made it easy to homebrew the coils and the 'island pad' style PCBs.
The transmitter stages are 8 MHz crystal oscillator, reactance modulator and multipliers for 24, 72 and 144 MHz. All stages, from 8MHz crystal oscillator to 144MHz multiplier, use BC109B transistors. Three 2N3866 stages amplify the output to 0.5W. A vintage antenna relay does the T/R switching.
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| Homebrew 2m FM rig - inside view |
It is based on G3OGR - OM F.G. Rayer's two articles 'Converter for 144-146MHz' and '144-146 MHz Amplifier', in his book 'Projects in Amateur Radio and Short Wave Listening' (1981).
These articles are also covered in '50 (FET) Field Effect Transistor Projects' by the same author.
http://www.talkingelectronics.com/projects/TheTransistorAmplifier/50FETProjects.pdf
3N200 insulated-gate, dual-gate mosfets are used for the preamplifier, amplifier and mixer stages. A couple of 2N918 transistors for local oscillator and first doubler are followed by a 2N2369 second doubler for 133MHz.
The quick and dirty 12VDC power supply was put together with junk box parts.
An aluminium baking tray served as the enclosure.
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| Crystals ground for the 2m FM rig |
Vintage 8 MHz crystals were ground by hand to the desired frequencies, using QSOs received on the converter and 'well-warmed' BC-312-D as reference.
The pads for FT-6U crystals and trimmers became redundant on account of non availability of the crystals. An 807 tube socket was found suitable to plug in all configurations of vintage crystals used.
With a ¼ λ Ground Plane Antenna, this rig served me well for both local and DX contacts till I could lay my hands on an ICOM IC-02A in the year 1990.
Related post: Simple ¼ λ Ground Plane for 2m
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