how to utilize two antennas?

[leeroi]

Hi,
I have 2 DB4 Multi-Directional Outdoor UHF antennas mounted on my chimney, each pointed in a slightly different direction to zero in on local stations. I have these connected via a simple combiner junction thingy I purchased at Radio Shack. The antennas are mounted vertically on my chimney with a distance of about 1 foot between them. There is a total of about 75 feet of coax cable between the antennas and the TV. I noticed an overall improvement in the signal over using just one antenna, although not as much as I had anticipated. What should I expect when I have two antennas working together like this? Is there a better way to utilize my antennas? (don't ask me why I have two identical antennas- it's a long story!)

Lee

[tigerbangs]

Unless the antennas are aimed in the exact same direction, they can have an additive effect on reception. Undoubtedly, you are experiencing some cancellation effect between the two antennas with the way that you have them installed. Without knowing your exact location and viewing situation, I would say that I would be more likely to suggest using one antenna aimed in the middle of the spread of stations that you want, and possibly use a preamplifier, especially if you are running more than one TV set. Preamplifiers are tricky beasts, however, and if you are in a very strong signal area, they can actually impede reception by overloading.

[leeroi]

I plan to continue using both of them. Do you think there is a better way to install/set them up so I don't get cancellation effects? If it helps to know my location, my zip is 28562. I live in a rural area. I can pick up 4 local stations: CBS, NBC, ABC and PBS. There is about a 40-50 degree compass spread in the transmitters

[tigerbangs]

Now that I see your TVFool.com report, I realize that you are trying to get VHF channels with 2 UHF antennas: WRONG! Replace one of the DB-4 antennas with a Winegard YA-6713 or an AntennaCraft Y5-7-13, and combine the two antennass using a Pico-Macom UVSJ antenna joiner, and you'll do MUCh better than the DB-4 on channels 10 and12. The DB-4 is NOT a VHF antenna, and you are losing a considerable amount of signal by trying to use a DB-4 for VHF reception.

[leeroi]

No that is not correct. I am accessing digital broadcasts via UHF for channels 7.1, 9.1, 12.1 and 19.1 and 19.2. The info at TVFool.com also indicates I should be able to access 14.1; my TV's autosearch acquired 14.1, but my signal strength for that channel is zero. Sorry if I didn't make my situation clear in my initial post.

[leeroi]

On second look- Duh!. Obviously, I am pulling in VHF stations since I am picking up channel numbers under 13. In spite of having a UHF antenna array, I get excellent reception for channels 7,9, and 12. Still wondering why I'm not picking up more on the UHF band, particularly 14, which is only 13 miles away.

[tigerbangs]

As I was trying to tell you: the cancellation effects of the two antennas are causing you to lose FOX: you need to replace one of the DB4 antennas with a VHF yagi and combine the two antennas as I suggested to you: believe me, I have done this more than a few times.

[leeroi]

Thank you.