Adam, It may be far enough out-of-band for the harmonic filter that it isn't passing as much RF to the antenna connection port, regardless of what the specs call for... I had an MSR2000 that was like that - it was in the commercial UHF band and worked fine, but when it got moved to 444.5500, it kept burning up the PA - melted the connections to the harmonic filter, even with silver solder. (We finally gave up on that one.)
Mark - N9WYS -----Original Message----- From: [email protected] On Behalf Of Adam Feuer Sent: Friday, May 08, 2009 2:49 PM To: [email protected] Subject: Re: [Repeater-Builder] First UHF MSF5000 Attempt Hmm??? The book at my friends shop said (if I read it right) that a C74 with the filter option was rated at 110 from the PA and 85 at the junction box which is why I'm concerned about my 71 watts. James Delancy wrote: > > > UHF models that are 110 Watts, are rated for that out the side of the > cabinet. This usually results in 160 Watts out of the PA. Then you > are down around 100-110 Watts after the harmonic filter and the > pre/post pass filters. > > James > > > Maire-Radios wrote: >> *well if it was 85 watts with 122.5 watts* >> *it would be lower at 110 watts and any be the 71 watts do the >> math should be about the same values.* >> ** >> *John* >> ** >> >> >> ----- Original Message ----- >> *From:* n2acf <mailto:[email protected]> >> *To:* [email protected] >> <mailto:[email protected]> >> *Sent:* Friday, May 08, 2009 2:49 PM >> *Subject:* [Repeater-Builder] First UHF MSF5000 Attempt >> >> Hello All, >> >> Attempted to tune up the TX side of a C74CXB today. The odds >> weren't really in my favor as I've never worked on a UHF MSF nor >> have I ever used a tracking generator. I brought the station to a >> friends shop and I used an IFR1200S for the tuning. >> >> I checked the station before I began and on 453.900 there was >> 82.5 watts at the antenna port and 122.5 coming out of the PA. >> So, I reprogrammed the station, adjusted the VCO, and then began >> to re-tune the 3 pole and 4 pole filter. I also changed the >> output power of the PA to 110 watts because I believe that is >> what the station is rated for. The new TX frequency is 441.950. >> >> When I was done with both filters, I checked the power at the >> antenna port and it's only 71 watts. I believe it's supposed to >> be 85. >> >> The PA looks very clean on the spectrum analyzer and the carrier >> is right on frequency. Again, I'm not the best at reading the >> scope while using the tracking generator but I did it the best I >> could for the first time. Is my output power OK at 71 watts or is >> something wrong? >> >> Thanks in advanced! >> >> Adam N2ACF >> > > > ------------------------------------ Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.325 / Virus Database: 270.12.21/2102 - Release Date: 05/08/09 11:43:00
