2 Antennas

[RED]

Is it possible to hook several antennas up at the same time to get better tx/rx? As I was inspecting a house today, I saw a "double adapter" for tv co-ax (ie. 1 antenna, 2 tv's). This got me thinking maybe it was possible to do in reverse. 2 antenna for 1 radio. I cant see any problems setting up(will still work regardless), but would it achieve anything?

When I was running an AM radio, i basically did the what i'm asking about above and believe i got better range but is a AM antenna, an AM antenna. With UHF you get different gain ratings.

Would say a 3Db and a 6Db antenna give me the distance of a 6Db on flat and the benefits of a 3Db in hilly country without the need to change antennas?

Or is this something noone's ever tried and i need to experiment? :smile:

[rebradio]

Hi Red,
It's common practice commercially to connect two (or more) identical antennas 'in phase' to modify the radiation pattern and improve the gain of antennas. The key is they need to be connected and fed 'in phase' for the benefits to be seen. The connecting cables are cut to exact lengths. If you don't you may cancel out the signal from one with the other. It was also common as you mention to mount 27Mhz antennas on either side of a truck cabin and get a boost that way, these also needed to be fed in phase.
As for combining a 3dB and a 6dB to get the desired pattern, I will leave that to other experts. I don't think so but I simply don't know!

Cheers,

Phill.

[RED]

I'm not familiar with the technical terms/slang yet. What is meant by in phase? I've done a small amount of research into what you've said and well, all i can say is my physics is pretty rusty. :???:

[rebradio]

Hi Red,
It's hard to explain phase without pictures.. I found an article than might answer some of your questions.
Have a look at..

http://www.repeater-builder.com/antenna/db-about-rf-communications.pdf

The repeater-builder web site has lots of cool RF stuff.

Cheers,

Phill.