This makes sense. I guess what might help is to find a single VHF bandpass can to put in front of the receive side of the duplexer.
How much does the power output effect the required filter attinuation? Right now I am running about 70w out would turning it down make much of a difference? From the charts I have seen it doesn't seem to be more than 3 or so db difference between 10w and 70w. Am I reading it wrong? Thanks, Vern On Wed, 26 Sep 2007 11:12:29 -0500 "Steve S. Bosshard (NU5D)" <[EMAIL PROTECTED]> wrote: > A transmitter may have broadband noise with considerable >noise content > at the receive frequency. The notch in the transmit >side removes > transmitter noise that may impair your receiver's >capability. In an > earlier post there was mention of a solid state >transmitter. > Traditionally tube transmitters have higher Q output >circuits as opposed > to wideband circuits in solid state transmitters, so a >solid state > transmitter may need more filtering. > > There are also combination band pass / band reject >duplexers and also > band pass only. Each has a characteristic suited for a >particular job. > Beware, a duplexer may pass an intended frequency PLUS >unintended > frequencies outside the normal band pass. I found that >158.100 radio > paging was being received by a dual band antenna, and >passed right thru > a 440 duplexer to cause overload in the receiver front >end. In this > particular instance the best solution was to go to a >monoband antenna. > > Wishing you best success, Steve NU5D > > > [EMAIL PROTECTED] wrote: >> Thanks for the great info as soon as we get the service >> monitor back we are going to try these things. >> >> I have already seperated the 2 sides and have seen much >> improvement so I think that this is really my problem. >> >> I do have a question about duplexers in general. I am >> sure that this is a dumb question but.... >> What is the purpose of notching out the receive >>frequency >> on the transmit side? Since I have 6 cans couldn't I >>move >> one of the cans from the transmit side to the receive >>side >> to give me 4 on the receive and 2 on the transmit? >> >> Thanks, >> Vern >> >> >
