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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  U3S single BS170 briongs already 1W at 5V! The PA is good 10MHz and lower but 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 filter now. 

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 and the ugly..  Left genuine Mitsubishi,  mid Ebay "good quality RD15HVF1" what appears to be an   IRFxxx  G-S = 1.29nF    re-stamped type  pins:  GDS instead of…