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Showing posts from July 5, 2018

U3S and 1-80MHz 5W eBay

Last year I have build 3 QRP-LAB U3S  multimode beacon transmitters.
The goal was  5W on all HF and 6m to be used as WSPR beacon on a remote location in PY
This goal was never reached.  the QRP-LABS  5W PA could only make 1W at 50MHz
3W at 28MHz  it delivers 5W at the low bands only.
The QRP LAB "5W PA" uses the IRF510 or  RD15HVF1  with 9:1 wide band transformer out
As simple as can be. The RD15HVF1 is a VHF 10W FET it should easy deliver 5W  at all bands up to 144MHz
f.i. the excellent 144MHz XVTR  (@ transverter-store) uses the RD15HVF Its output is over 10W But whatever i tried with the QRPLAB 5W PA at 12V  3W at 50MHz was the max
I need a conservative reliable 5W that can run 24*7
I gave up the time consuming experiments had to accept the 3W at 28 MHz 12V

Recent found some eBay RF amplifiers that looked promising.
The 2W   1-930MHz  f.i.  2 of them could make 4W?
But 0.5W  maximum carrier at 5V   not the stated 2W
useless as PA for a U3S


Another   2 -80MHz 5W  amplifie…