Differences

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--- radio:projects [2020-06-02 21:12] – cazagen
+++ radio:projects [2022-02-09 02:18] (current) – river
@@ Line 6: / Line 6: @@
 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)
-  * Icom (I forget the model, will update soon) (HF)
   * Yaesu 7900R/E (V/UHF) (Loan from Ben C.)
+==== Amplifiers ====
+There is a 2M Linear amplifier, "The Polar Electronic Developments EDL144" donated by Colin. Notes on it copied from his email follow.
+https://worldradiohistory.com/hd2/IDX-UK/Amateur-SW/Archive-Short-Wave-Magazine-UK-IDX/IDX/70s/SWM-1977-02-IDX-20.pdf
+It has a cool old power valve inside - http://www.r-type.org/exhib/aag0119.htm I think.
+I found details, and circuit diagram here: https://www.g1ogy.com/qqv-0640.html
+Better photographs of the inside are here: https://pa0fri.home.xs4all.nl/Lineairs/EDL144/EDL144%202m%20amplifier.htm
+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. http://www.zl1bjq.co.nz/qqe06p2.html or http://www.vk3nx.com/files/50MHzAmp.pdf
+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.
+Regards,
+Colin
+"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."
+==== Antennas ====
 The lab currently has the following antennae (for transmitting):
@@ Line 15: / Line 43: @@
 There are various other antennae on the roof for SDR and ADSB purposes. Details about these can be found on the [[:roof|roof]] page