antenna mount ???

[deltaten]

Any (electronic/RF) reason I shouldn't/ can't mount small VHF whip on there outboard end of a spreader?
I assume some directivity due to mast
Not a bunch weight or wind resist from a 24" s.s. whip

TIA,
Paul

 

[The Garbone]

Loaded question. I have my AIS on the spreader and voice on the masthead. The spreader location besides being lower the metal mast will cause propagation irregularities and some minor reception issues.

The spreader mounting could be and issue if you are attempting to listen a conversation down in the noise or hoping to get lucky on talking far away. For AIS I tend to think this is not as big a deal but masthead is better.


One thing , our boat was hit by lightening, masthead antenna is now vapor but the spreader one is fine.

.

 

[Benny17441]

VHF is line of sight signal so the higher you go the farther it can communicate.

 

[Don S/V ILLusion]

It's not the spreader about which you should be concerned but rather the shroud being too close to the antenna. The proximity in the same plane will have a parasitic effect on the antenna, the amount of which cannot be reasonable anticipated. The shroud can also detune the resonant length of the antenna.

Will it work? Probably.

Will it work as well as another location? Probably not.

 

[Bill Roosa]

Agree with Don, the spreader guy will have a noticeable effect on the reception and totally wack transmission. Reception will not hurt the radio but when you key the PPT the antenna HAS to be able to radiate the energy or it gets reflected back to the transmitter with bad results. The guy wire will cause the antenna RF impedance to change away from the 50 ohm the system is designed for.
If the spreader is the only option place it in the middle between the mast and guy and try it out on 5 watts transmit power first to see if the unit shuts down due to impedance mismatch