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Radio Projects

There are a number of projects in the pipeline relating to amateur radio; these will be updated as they progress.

Lab Radios

The lab currently has the following radios:

  • Icom IC-761. HF Transceiver. Modified for use with external power supply as internal broke.
  • Yaesu FT-757GX (HF)
  • Yaesu 7900R/E (V/UHF) (Loan from Ben C.)


There is a 2M Linear amplifier, “The Polar Electronic Developments EDL144” donated by Colin. Notes on it copied from his email follow.

It has a cool old power valve inside - I think.

I found details, and circuit diagram here:

Better photographs of the inside are here:

He (Colin's Dad) would have used it with an Icom IC-211E radio which (from memory) had a 10w output - I think the amplifier produced maybe around 100w or so, but this is from old memory so take with a pinch of salt.

I suspect it could be modified to work on HF - e.g. or

It probably hasn’t been powered up since 1981 or so - so no idea what condition it might be in - but it might be interesting for radio folks (assuming there’s a large enough dummy load!). Alternatively, if it’s not suitable for hacklab and anybody wants it please feel free to take it, or add it to the ‘dispose’ list.

But - high voltage, high power valve stuff = dangerous so be qualified.



“This linear amplifier for 144MHz employs a rugged push-pull tetrode operating in AB2 for the linear amplification of transmitters in the 10-20 watt range. A single stage dual gate mos-fet pre-amplifier is also fitted to enhance the performance on receive. This has variable gain, which is accomplished by varying the potential on gate 2. This produces a gain of approximately 20db in the maximum gain setting. Under strong adjacent channel signal conditions it may be necessary to reduce the gain to prevent cross-modulation effects in the associated receiver. R.F. input and Antenna connectors are the familiar S0-239 and are mounted on the rear panel and clearly marked. Also mounted on the rear panel are the bias control potentiometer and the mains fuse.”


The lab currently has the following antennae (for transmitting):

  • Off centre v-shape HF Dipole, this is mostly tuned for 40m/20m
  • V/UHF Double J-Pole

There are various other antennae on the roof for SDR and ADSB purposes. Details about these can be found on the roof page

Other Projects

radio/projects.txt · Last modified: 2022-02-09 02:18 by river

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