AMATEUR RADIO CIRCUITS
AF Filter / Amp. and Sidetone Generator
This page contains circuit diagrams and construction notes for various projects including Amateur Radio Tranceivers (for VHF and HF), solar and wind power regulation and links to pages with other electronic circuits.
Transceiver IF Strip
Guage size when printing using 0.1" pitch for IC1
TRx IF Strip (click to enlarge) This circuit is designed for use with standard 10.7 MHz xtal filters, the 9 MHz xtal filter available from G-QRP Club or a homebrew filter in the 4 to 21 MHz range, using individual xtals. It features a novel bi-directional amplifier at each end of the filter which performs impedance matching to the filter, Tx-Rx switching and of course amplification. There is also some on board audio filtering. various mixer types are possible, but need to be bi-directional ( eg SBL-1) if the IF strip is to be used as a transceiver.
CARS CONSTRUCTION COMPETITION
The circuit below is what it is possible ( ie. A complete AM transceiver) to build with the components supplied for the CARS 2006 construction competition. All the components of the kit are used in this example. What was actually built in the two hour time limit by a team of four was somewhat short of this. The circuits actually built are listed on the CARS website, which can be accessed from the links page. If you would like a kit of components for this challenge, e-mail me: John@g8seq.com
In Rx mode the o/p 1 is taken to the MC3340 VOGAD and then to B' of the LS driver amp ZTX680B. The speaker must be in position AA' and BB' linked). In Tx mode the speaker is connected to BB' and the amplifier o/p AA' is connected to the PA stage ( with the gnd connexion removed from the AF amp.!). No switches/keys were supplied with the original kit; change-overs were expected to be done by swapping over wire links!
Last updated 4th April 2015. 73 de John G8SEQ