only room for one antenna ...

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brin831

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we really only have space for one antenna but need to run 2 tx and 2 rx off of it ... basically need to combine 2 duplexers from repeaters ...
can this be done and this is what i was looking at http://www.e-meca.com/rf-power-divider/Hdivider_specs.php?hdivID=6&specsID=23

thanks for all the help i have learned so much just by reading this board over the last few months !

oh and looking at aprox 15 watts on both tx ... so nothing to powerful ...
 
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brin831

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concord nc
does that really even make a difference ?? haha

its actually a roof placement so yes and no?!?

about a 50 ft coax run ...
 

cquirk

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Hi what frequency or band? are the radios??

I run UHF and VHF off 1 antenna

VHF Low and High off 1 antenna


But VHF high and VHF high or UHF high and UHF high similar channels IE 150 MHZs or 460s on both radios, not so good, lots of desense lots of recievers dropping out and not coming back. You can put notch filters duplexoors you would use for repaters etc and other stuff but gets kind of involved after a while

I run with duplexors as you suggest, with a few issues but nothing serious. Use COMET duplexors avaialable from your local ham radio place
 

brin831

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concord nc
well we already have the duplexer's tuned in to specific freq's and currently have 450 to 470 yagi's we use with them ...

i'd prefer to have this be a stand alone setup because we are trying to seperate our stuff to use at another location this is a temp. setup so trying to keep it as plug and play run a piece of nice coax and be done rather than integrating into anything else that is there ...
 

ramal121

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Sonoma, CA
we really only have space for one antenna but need to run 2 tx and 2 rx off of it ... basically need to combine 2 duplexers from repeaters ...
can this be done and this is what i was looking at H-Series Power Divider/Combiner Specs

thanks for all the help i have learned so much just by reading this board over the last few months !

oh and looking at aprox 15 watts on both tx ... so nothing to powerful ...
I think you are looking at this backwards. A power divider is to take the output of a transmitter and separate it out into two different loads (antennas).

What you are looking for is a combiner. These cost big $$$. A typical combiner, such as used at a commercial repeater site, will consist of two components- the receive multicoupler and the transmit combiner. Each of these require their own antenna. Since you have only two repeaters, spend the money on good coax and antennas and forget about twisting the repeaters together.
 

zz0468

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What you want to do IS quite doable, but you'll either have to shell out the money, or be creative technically and fabricate something yourself. Your original idea would be an intermod nightmare.

What's done in situations like this is, all the transmitters first get combined, then the combined transmitters applied to a duplexer that's designed to handle both the power, and the required frequency spread. The receive port of the duplexer (again, designed for the required frequency spread, and isolation) is applied to a multicoupler, to split to all the required receivers.

Finding or building the broadband duplexer is going to the difficult part, but that's how it's done. It's rather easier if the two repeaters are fairly close in frequency. But if the transmitters are TOO close in frequency, you'll need a hybrid combiner, not a cavity combiner.

$!

A possibly cheaper alternative is to use a dual antenna - two antennas in one housing, and two separate feedlines. They're out there...

The fact that this is a temporary situation almost makes it economically unfeasible. Technically, it's done all the time. But it costs effort and money that might not be worth it for a temporary solution.
 
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