Idiot’s guide to RF amplifiers
Sooner or later you’ll find your self wondering “Isn’t there a way to get more range?”. Sure there is, there are more actually. The best would be to improve your antenna system, but sometimes this isn’t possible for objective reasons. It is also possible that you allready have very good antenna system as it is. You’ve got to increase your power….
Universal bipolar power amplifier
Here are a pic of a VK200 wideband choke and a table of transistors that you can stick into this amplifier. Emitter leads of the power transistor have to be kept at minimum (every single additional millimetre means less gain and less output power). Use large (appropriate) heat sinks. Do not strain transistors too much when you mount them, ceramics can break. If you can’t max the amp with shown trimmer caps, use bigger values or add 10-22pF in parallel. Some coils might need a winding more in some cases. Need printed circuit board for this? See the table below to order the PCB…
Amplifier designs from Motorola (1Kw, 300W, 600W)
Here are the 1KW amp, 600W amp, 300W and 150W amp and these usefull datasheets; Amp1, Amp2, Amp3, Amp4. These are all extremely valuable to any builder, have a look and enjoy.
Earthing straps, mounting and PCB example.
If you are not experienced please buy a complete module or a rack-mounted completed amplifier. Pallet amplifier is often enough for even inexperienced builders to get some results. These pallet amplifiers are without filter but relatively easy to use. Here is how such a pallet amplifier looks like:
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