Tuuk wrote:
Hi

Hope I can get some advice from the experts about my antenna.

I have a 50ft self supporting tower, my goal is to put 2 antennas up.
One dipole and one omni.

I have an old omni direction antenna that I wish to put at the top, it
has 3 traps in it with no writting on it so I am not sure what bands it
will be suitable for however I have a pretty good tuner so I can use it
on most bands. I also have one of those brackets that allows me to use
ground planes with it, 4 ground planes aluminum and longest possible is
what I try because the wind brings them down fast.

Second is a simple dipole, I think it is 60 foot each side or little
more however it hangs over the trees on each side so it isn't perfectly
straight. It is connected to a ladder line then connected to my tuner
then my Drake TR7.

These two seem to work OK for me in the past, I hope for some advice on
these and please answer the following questions.

1- Any idea what the omni direction antenna with the three traps is for
which bands? It is about 22ft long with the three traps on the bottom
half, old aluminum antenna.

*probably* 20, 15, and 10 meters but "mikea" has the right idea,
suggesting you try a SWR analyzer on it.

2- What about those ground planes? Are they necessary?

Yes, probably. (there were some vertical antennas designed that don't
need them but this doesn't sound like one of them) Usually with a
vertical antenna, the ground plane is half the antenna - to put it
differently, if you don't put up the ground plane, half the antenna is
missing.

3- On the dipole, I have a 1:1 balun in the garage, should I use this
with the dipole? The antenna tuner already has some device to balance so
is it necessary for the other balun? Someone told me it is so I must ask.

If you're center-feeding an antenna with ladder line then I don't think
there's any need for a balun at the antenna. And if your tuner has a
balanced output for connecting the ladder line, then you don't need a
balun at the shack either.

It would be more useful if you were using coaxial cable to feed the dipole.

--

Doug Smith W9WI
Pleasant View, TN EM66