Quote:
Originally Posted by HTNut
Another quality post there Piggie, great links too. I often see OTA posts that talk about "out of phase" problems with dual antenna setups. Would something like that apply here? |
If you look below to the Two Antenna Trick, that answers your question. Yes it makes a HUGE difference if the two baluns are not in phase. Yours truly hosted up two yagis once with a rain storm coming (lame excuse), went inside and the results were dismal. After the rain I walked back out and let out a huge oh dang it!! (worse but it will get censored). I put one of the baluns on backwards
! So it's not too hard to screw up, and that was with built in baluns you can look at and tell (in case if anyone wonders if I totally screw up!).
What is harder are the standard baluns. They look the same on both wires, so you pretty much have to test them by rotating the antenna looking for your peaks. If pointing at the station is weak, but 20 to 40 degrees off the station on either side is a peak, you have the baluns backwards. This applies to two identical antennas pointed in the same direction horizontally stacked. If you vertically stack two, all you can do is change it and see which is stronger, where stronger is correct.
That said if you point two antennas in different directions, in particular two different models it is nearly impossible to guess at the resulting patterns. Of course the reason to go this would be to not use a rotor but have strong enough signals to suffer 3.5
db of loss. You can model the result on good software, just put them up and see what happens. Here too, you can try reversing one of the baluns to see what effect it has. Normally doing this one is trying to generate two lobes so rotating the antenna checking your nulls and peaks would be a very good idea, with different baluns wiring and orientation of one antenna to the other.
