Any preferred omnidirectional UHF antenna, horizontal polarized ?

[Externet]

Hi. Do you have any preference for one of those performing antennas; even a do-it-yourself ? The yatch ones are not impressive. The modern 'panel' ones do not convince me as being omnidirectional. Any others with decent gain ? Say +6 dBd ? ~600MHz would work...

 

[sagor1]

The only horizontal, omni-directional antenna I've used is a "clover leaf" type, with 3 equal horizontal lobes in a clover leaf pattern. No real gain. You can stack those for more gain, so you would need 4 of them phased together for about 6dB gain. Gain for one antenna is not much better than a regular dipole (3.0 dBi vs 2.1dBi for dipole)

 

[unclejed613]

Any others with decent gain ? Say +6 dBd ? ~600MHz would work...

omnidirectional and gain are two words when used together usually refer to a vertical antenna such a colinear or 5/8 wave. for horizontal and nearly omnidirectional you could try a turnstile antenna. stacked turnstile antennas would provide gain.

 

[Nigel Goodwin]

As already mentioned, gain is produced by providing directionality - the more directional, the greater the gain.

To give gain on an omni-directional horizontal aerial the directionality is reduced vertically, so if you think of the vertical directionality as a 3D figure '8' on it's side, the top and bottom of the circles are squashed, giving more gain in a narrower (vertical) beam - and less wasted going up and down.

 

[rjenkinsgb]

You could stack a few halos and combine them with a phasing harness??

Halo antenna - Wikipedia

en.wikipedia.org

Not exactly a brilliant approach, but a horizontally polarised omni is not that common.

 

[Nigel Goodwin]

You could stack a few halos and combine them with a phasing harness??

Halo antenna - Wikipedia

en.wikipedia.org

Not exactly a brilliant approach, but a horizontally polarised omni is not that common.

It's very commonly done on TV transmitters - however, it's usually done by separate arrays in each direction (all usually hidden away in the white tube on top of the mast).

We had occasion to find this out when our local TV transmitter at the town where I used to work went 'faulty' - it was perfectly OK at the town I worked in, but in the other direction signal all but disappeared completely. I contacted the transmitter people (now Arqiva - not sure who it was at that time?), and they sent their people out - and as we had VERY close contacts with them, they called in to see me and explain what had gone wrong.

Basically there was four aerial arrays, facing different directions, and one of them had died - it took them a few days to source a replacement aerial, and to fit it.

Personally I've climbed that mast twice (it's 45m high) - before the transmitter was fitted, just after the mast was constructed - and I wouldn't like to think I had to try and replace one of the aerial arrays. I suspect those kind of people have to be a bit mad and it's not like it's a big mast or transmitter either.