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Showing posts from April 15, 2017

U3S Ultimate3 and 5WPA experience

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Sorry enough  after just a  few day's testing the U3S / 5WPA  at 50 / 28 / 21  Mhz   Output was lost  after 15:42Z  Monday 17-4   The FET RD15HVF1  died  possible by statics? 1 genuine left but repairing this 5W PA  ? A lot of effort and trouble  to bring 1W to 4W at 28MHz  The U3S single BS170  already is 1W at 5V! I thought that it would be an easy job to have 5W+ with the 5WPA RD15HVF1 But no way! something must be wrong somewhere the power gain is 0 - maximum 6dB only The 5W-PA is good for 10MHz and lower but very disappointing at higher bands.
The signal from the U3S straight from the Si5351a needs to be filtered before it drives the RD15 and after the 5W-PA again i think  Far from sinus shaped signal at the output of the PA behind the LPF filter. 

Be aware! the fake RD15HVF1 is still offered at eBay  5 for 5$ It was only my 2nd bad buy at eBay  of many purchases.      After solder tip eating  SOLDER core wire CF-10 B-2  0.6mm   that smells like cat pee.  The good  the  bad …