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Old 9-Jan-2012, 8:09 PM   #12
ChrisAntennahead
Junior Member
 
Join Date: Dec 2011
Location: Stamford CT
Posts: 19
Cool

Quote:
Originally Posted by Dave Loudin View Post
Lucky? Yes, but over time you will see how often this will be a true problem. You can convince yourself that our theory (and that's all we can offer) is correct the next time it happens. I hope you won't have to test it, though!

Matching lengths of RG-6 won't eliminate the problem, just move it to a different channel (well, that actually might be a solution!) The antennas are still physically separated, so one signal path to the combiner will always be longer than the other.

There is no way to guarantee constructive combination of separate antennas that cover the same frequency band. There are special combiners that combine UHF frequencies from one port with VHF frequencies on another port and there is a special device, called a JoinTenna that can insert one channel from one antenna into the wideband feed of another.

The most reliable way to feed the signals from two antennas where their frequency ranges overlap is to NOT combine them. Run separate cables to an A/B switch by the TV. Like having to use a rotor, this has operational disadvantages for recording programs.
I did need a UVSJ combiner at my apartment where the DB8 handled UHF and a dipol handled VHF-Hi, so I'm familiar with that type of combiner.

I'm also wondering if, based upon what i read in those links, if my antennas were closer together(on same or adjacent masts) would some of the phasing issues be resolved - or just shifted around on the spectrum. This is ineresting!
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