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Showing posts from January 14, 2021


  Picture shows the U3S -deluxe  with PA build into the U3S housing (deluxe). Powered by 12V  1.5A max 1 UA7805 for the U3S 5V, A IRF9510 P-channel + NPN BC557  to make TX 12V switched by the  U3S "key" and an connected  UA7805 for TX5V.  The 5 band LPF board the U3S with the 80m LPF0 not visable the small coax cables to the underside of the U3S to place the LPF 0 and 1 2 3 4 5 behind the PA .   This multi mode multi band automatic beacon transmitter is a best seller by QRP LAbs kit by Hans Summers I  build 3 of them, one time they should run as WSPR beacon PU7ZWT in HI11ln  N-E Brasil Some issues : Had to replace the original cheap PC 27MHz kristal with a far more stable TCXO Taitien the blue potmeter PCB More output: I use an eBay 2 trap HF VHF PA having a RD15HVF1 power Mostfet in the final RD15xxx Mitsubishi  power MOS-FET are  used in many rigs like the K3 LPA it can operate from HF to 450 MHz. Its Source is  the middle cool flange that makes cooling a lot easier. This e


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