Thanks, Bob. Yeah, I know that those PIN diodes get blamed for lots of stuff that they don't really cause. :) I was getting a solid 90+ watts out on 10 Meters, with ALC, after I rebuilt the PA deck. Perhaps not the best it could do, but certianly adequate. The power level drop does not concern me so much, as we all know you can work 10 with a wet noodle when the band is open. Rather, the lack of ALC makes it easier to overdrive something under these conditions. I can level the output with my SP-75, and a check with a local indicated that I was OK at that level, but it still needs to be fixed later. And, of course, I'll check the PIN diodes again...
73 -Jim On Sat, 11 Dec 2010 09:51:48 -0800, Robert Fish wrote: >Hi Jim, >I think you are probably aware of the Pin Diode issues on the higher >bands. I think that affects the whole band or bands (15 meters too). >Not just a portion of a band. It does seem like your LPF's are rolling >off early. > >I am using a TR-7 on the 10 meter contest right now as well. I am barely >driving a linear amp (20 watts) to get me up to 150 watts with it. >Why not just run a KW. You ask? It brings the neighbors and the family >out of the wood work if I run 1000 watts on 28 MHZ. > > >Bob K6GGO > > >> Hi gang, >> >> Here's an odd one. Fired up the trusty 7-Line this weekend for the 10 Meter >> contest, and I noticed that I wasn't gettng any ALC action and power output >> was >> low. Further investigation revealed that the power drops from about 95 Watts >> CW >> at 28.0 to around 65 Watts at 28.4 MHz into a DL-1000 dummy load. The PA was >> rebuilt a couple of years ago per the article on the WB4HFN web site, and has >> been rock solid until now. My first inclination without cracking the manual >> is >> a faulty component in the output lowpass filter, or perhaps some other filter >> stage somewhere. >> >> Any thoughts? I'm not going to bench the radio in the middle of a contest, >> despite the fact that the propagation gods are ignoring me again, just trying >> to formulate a plan of attack. >> >> 73 >> >> -Jim >> >> >> -- >> Ham Radio NU0C >> Lincoln, Nebraska, U.S.S.A. >> TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, >> GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! >> >> "Give a man a URL, and he will learn for an hour; teach him to Google, and >> he will learn for a lifetime." >> >> HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ >> http://radiojim.exofire.net >> http://incolor.inetnebr.com/jshorney >> http://www.nebraskaghosts.org >> >> >> >> _______________________________________________ >> Drakelist mailing list >> Drakelist@zerobeat.net >> http://mailman.zerobeat.net/mailman/listinfo/drakelist >> >> > > -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
