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On Jun 26, 2004, at 11:03 PM, MILAREPA wrote:

Dear forum,
The IRF510 and 2N2218 is not available here in INDONESIA,
?
-Could you suggest an alternative for 'linear amplifier module' ?
?
-Can I just use:
HF BANDS QRP LINEAR AMPLIFIER?- 4WATT or
TEN WATT LINEAR AMPLIFIER all by Harry Lythall - SM0VPO
Since 2SC.....( Japanese) transistors are available here.

Both those circuits will work fine, as will most any other QRP amp
circuit. A broadbanded circuit is easier to build and use because it
requires no tune-up and is less likely to have a parasitic oscillation.
Be aware that those two amps NEED a low-pass output filter. For 20M,
the BITX20 filter will be fine. For other frequencies, most popular
radio handbooks have equations and design examples for the frequency of
interest.

Readers are reminded that Harry SM0VPO likes to share his work, but
doesn't like seeing others pirate it or claim it as their own. So be
sure to provide attribution (as was done here) when you share his
stuff. He has the best homebrew radio site in the world, and we'd like
to encourage him to keep it online, by respecting his work and his
copyright.

Jim N6OTQ