--- In [email protected], "cworksmidwest" <[EMAIL PROTECTED]> wrote: > I'm building a VHF high band repeater... on a tight budget. I have > everything except a duplexer. I need some recomendations on cheap > abundant duplexers that will do the 600Khz split. Max power I'll be > using is 50 - 75W so recomendations for some Monster wacom or TXRX > duplexers that can handle a bazilion watts do not need to be posted, > besides, I probably wouldn't be able to afford ANY used wacom or txrx > duplexer sets. >
Dave, Others may have different suggestions, but in my view, 50 to 75 watts is a high powered repeater. 15 watts is probably sufficient given the fact that your repeater antenna is likely to have some gain to increase the ERP, and depending on the radios you're going to use, you might even want to run lower TX power. Consider using separate antennas, with the receive antenna above the transmit antenna in the null of the radiation pattern (e.g. directly above the TX antenna by a few wavelengths). With low TX power (5 watts) and vertical isolation, you might be able to get by without a duplexer and still have a workable repeater. On some sites, separate TX and RX antennas are obligatory, and you get your RX signal from a "community" receive antenna. This is the case on Santiago Peak in So. California where they must have hundreds of transmitters, and far fewer shared receive antennas. On these systems, the cans are used for band pass -- the band reject idea is a bit more difficult since there are so many other TX signals in the vicinity it would be hard to know which one to notch out, or which dozen. And with community receive antennas, the idea of a "duplexer" isn't part of the equation as it is when trying to use a single antenna for both TX and RX is the objective. Hopefully this is helpful. Jeff Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
