What aerial would be best suited for mounting on the side of a mast .I was gonna build a j pole but I fear the structure would interfere with swr?

How far from the structure can you get the antenna? You can use the structure as a reflector to direct your signal (assuming that you're on the right side of the building!). A J-pole will work, but you need to get it as far away from the structure as possible. Can you get any part of the aerial above the roof?

I think mounting the aerial off the side of any metal structure could cause the signal to be blocked (nulled out) towards the other direction, I think you need to be at least 2 to 3 metres away maybe even more with some antennas.

....So if possible try and get it as far towards the top as possible, unless of course for some reason you want to null out the signal in the opposite direction...

I want it to be nulled in the other direction.There are other aerials already mounted on the top of the mast

Bton-FM wrote: ↑Sat Feb 15, 2020 10:00 pm I want it to be nulled in the other direction.There are other aerials already mounted on the top of the mast

That doesn't mean you won't affect them then, being just a few metres away!

... I was meaning the towns that are a few miles away in the opposite diirection away from the aerial...

Yeah that’s what mean I’m not interested in covering the towns in the opposite direction

Oh OK,

....Probably be better to mount it as closely as possbile to the tower, then

Try a half-wave from the tower - the tower will act as a reflector.

ok i'll try that