[hpsdr] Munin - improved results (C25/C26/C27)

[Ken Shutt]

Exactly duplicates my Munin experience (Excluding XYL assistance).   The board was pitted under the 470 pf capacitor.  I replaced the caps with 4-220 pf/500v caps and rewound L4  (Thanks to Don Waddle for the teflon wire) and got 100 w on all bands except 6 m which had only 50 w output.  I am using Gerd’s Penolpe exciter board.

73 de Ken W5KQ

From: Tom McDermott 
Sent: Wednesday, January 15, 2014 11:10 PM
To: hpsdr at lists.openhpsdr.org 
Subject: [hpsdr] Munin - improved results (C25/C26/C27)

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I removed my brass tube version of transformer L4, and using replacement teflon wire generously sent by Don Waddel, and braid from RG-8X, my XYL rewound L4 to look like what was intended. She did a perfect job of course (compared to my 5 botched attempts). The new transformer made the performance much worse, 100w on 80m, a few watts on 10m, and virtually no power out on 6m.


Then replaced C25/C26/C27 with four 220p / 500V capacitors. In removing C27 (the 470p capacitor) I noticed what looked like a crater in it. Desoldering, it came off the board in two pieces, and there was a burned spot on the PC board underneath (where the 'crater' apparently went all the way through the capacitor). The cap was cleanly cracked all the way through. 


That seems to have completely fixed the problems. Am getting 100 watts peak (using two tone test) 80m - 6m with good looking two-tone waveforms (no compression).


-- Tom, N5EG





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