On the comment below all I can mention is from my experience which may or may not be valid in this case. When running amplifiers through diplexors as suggested I have damaged the out put transistors on both units, no I am not sure exactly what did it but as both amplifiers failed my guess is as one came up to full power and the other went non linear something happened and the diplexor failed to isolate as desired and expected.
If anyone can sort out what happened let me know --- On Wed, 2/24/10, Kris Kirby <[email protected]> wrote: From: Kris Kirby <[email protected]> Subject: Re: [Repeater-Builder] dual band convertacom To: [email protected] Date: Wednesday, February 24, 2010, 11:01 AM On Wed, 24 Feb 2010, hitekgearhead wrote: > What I would like to do is parallel these two amps with some kind of > switching/duplexer setup so that I could easily switch from VHF to > UHF. > > My initial idea was to run an antenna switch from the convertacom to > the amps so I can manually select which one the signal goes to. Then > on the output side of the amps I thought about using an antenna > duplexer on the output of the amps to feed the antenna. I was also > thinking of running a switch to alternately select which amp was > receiving DC power, but I don't know if that would be necessary. > (Could I leave both amps powered on in this situation?) > > So, does this sound about right or am I going off the deep end? Buy two duplexers (diplexers) from some ham source, put one between the MTVA and the amps, and the other between the amps and the antenna. No switching needed. If one really wanted to get wonky, you'd put another MTVA in the car and use a linear dual-band HT amp, but you'd have to look at the third-order intercept points on a spectrum analyzer to make sure the amplifier doesn't create mixing products, and alter the drive level of the two HTs to make sure the amp doesn't go non-linear when trying to amplify 145MHz and 440MHz at the same time. -- Kris Kirby, KE4AHR Disinformation Analyst ------------------------------------ Yahoo! Groups Links
