Hello Dave. I have a repeater working without a duplexer with 10 watts TX. I work with 2 seperated omni antennas. The Tx antenna a little lower on the tower like Jeff says and it works great! 73 de Eric -- ON4HF ( sysop ON0DST)
Jeff wrote: > --- 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/ > > > -- Amateur Radio Station ON4HF Eric Knaps Waterstraat 30 B-3980 Tessenderlo Belgium Tel. +32472985876 homepage : www.qsl.net/on4hf Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
