Re: boosting the power on 28 MHz #ubitx
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Did you try putting about 330pf across the primary of T11 (PA output transformer). That will make a big difference...
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Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com Like us on Facebook! Moderator ¨C North American QRO Group at Groups.IO. email: bill@... -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Skip Davis via Groups.Io Sent: Saturday, May 12, 2018 1:27 PM To: [email protected] Subject: Re: [BITX20] boosting the power on 28 MHz #ubitx Allison I tried the 220pf cap on RV1 and didn¡¯t see any gain at 28 MHZ. I also tried removing the feedback resistors in the finals suggested by Farhan without any gain. What I also have done was the capacitor/choke mod suggested by Howard for the driver stages and that has worked. With RV1 set to 10 watts on 40 meters I now get about 2.5 watts on 28 MHZ up from the 1.25 - 1.5 watts before. I also see about 8 or 9 watts on 20 meters. I¡¯m running Ian¡¯s firmware I think version 1.06 something. Skip Davis, NC9O --- This email has been checked for viruses by AVG. |
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