Fiberglass VHF Antenna advice.

Red Fox · 22 August 2016, 17:24

I have no A frame but want to get a fixed vhf. Does anyone have a (Supergain Portofino) 2.3m Fibreglass Powerboat VHF Antenna and would it be ok on the transom instead of the popular whip aeriel on an A frame? If it is advertised as for 'powerboats' and popular on most of the smaller fishing vessels that have them on the cuddy, would it be suitable on my zodiac? I carry a handheld vhf but just want the security of more power. Over.

Poly · 22 August 2016, 17:44

The problem with mounting on the transom is the Base is actually lower than handheld. You may find the benefits of the length are lost. I have no idea how that particular antanae is configured, but usually the advice is to avoid very high gain on small ribs.

treerat · 22 August 2016, 18:07

I've seen them on the console - my whip is mounted as such. Not as good as the A-frame but not a hope of routing cables at the time.

jwalker · 22 August 2016, 18:14

I'm sure it would work but I'm not sure how well because it's likely that the sea will act as a ground plane, so you'll be using an antenna that is designed to be used in free air away from a ground plane in the vicinity of a ground plane and this will mess with the impedance, which should be 50 ohms.

Internally the a active element is likely to be a 'J' antenna. This is simply a length of wire inside the outer which bends back up inside the fibreglass outer a set distance to provide impedance matching. The actual inside layout may be a little different but the principal will be the same.
For info - The cable feed is taken from each side of the bottom of the J and will therefore appear as a short circuit if checked using a meter.

Red Fox · 23 August 2016, 21:49

Interesting info guys and thanks. Does anyone know where I can get a ss pole and fitments for attachment to the transom onto which I can attach a whip aeriel as an alternative? One that can be lowered for storage in the garage would be ideal.

Poly · 23 August 2016, 22:48

Quote:

Originally Posted by Red Fox

Interesting info guys and thanks. Does anyone know where I can get a ss pole and fitments for attachment to the transom onto which I can attach a whip aeriel as an alternative? One that can be lowered for storage in the garage would be ideal.

I cheated and used a stainless prom handle - and some stainless clips (on the back of a seat but transom would work too) and then aerial just clamps on top - folding clamps are available.

matata · 24 August 2016, 07:40

Look at a site called Salty John. He is very good and only sell quality and tested stuff. Nik

Red Fox · 24 August 2016, 18:53

thanks Poly/matata. Salty John and Sea Screw seem to have what I need.

Red Fox · 24 August 2016, 18:57

Last (I think) question on this, what height is the base of your Metz aerial?
...oh, and is your Metz the 34" one?

Red Fox · 24 August 2016, 21:14

Sorted thanks.