Antenna HDTV - - Adding UHF to same mast as VHF antenna?

Question

Added a UHF/HDTV antenna (multiple planes) to my existing
VHF (single plane) antenna on the same pole (mast), with twin lead wire,
I connected the VHF to the UHF -- from that UHF connection, I connected the twin lead leading from the TVs below.
I lost some of the broadcasting signals from the original VHF only configuration.
Therefore, another change --UHF only connection --
Now I have more stations, with fewer screen freezes (pixelization moments)
However, this configuration has dropped a couple of stations I originally received from the VHF Only configuration.

I was hoping I would have the best of both worlds with the combo configuration -- It didn't work -- Why ??

Is there some canceling out, or other confilict with the combo set-up?

Any help will be appreciated. Thanks

Answer 1

Your main technical fault is joining the two antennas directly with twin lead. The right way to do what you want to do is install a 4:1 balun with a 75-ohm coaxial output jack on each antenna (any commercial TV antenna purchased in the U.S. in recent years should already have one). Connect both jacks to the two input ports of a low loss combiner (not a splitter), and from that a single run of coax to your set. Retire the twin lead.



However, there's no guarantee that this arrangement will give you the optimum performance you expect. The spacing between the VHF and UHF arrays could be a problem. What you've done very possibly could be improved upon by simply installing a quality VHF/UHF antenna.

Answer 2

there is a long list of reasons why you just can't connect the twin lead from the two antennas together. What you can do is get a VHF/UHF combiner. It has 3 connections, one for the VHF antenna, one for the UHF antenna and one for the feed to the TV set. It may not be easy to find a combiner that has all twin lead connections. you may need to also get 75 ohm balun(s) to convert between twin lead and coax.

Answer 3

I'm not much of an antenna expert but the first thing that came into my head was you could have some sort of strange effects (phase cancellation, etc) unless there is actually some sort of isolation between antennas. I've never used this but I believe this is what a device like this gives you.



http://www.antennasdirect.com/antenna_combiner.html



Also, I'd run those twin leads into a impedance matching transformer and change it to RG6 as quickly as possible.



Also, you might try a preamp.