Antenna Placement

[jared]

I was wondering why i dont see people mount their VHF antennas on the shroud spreader? It seems like a nice safe place from lightning and protected from jib torment. I would run insulated support(s) to keep the whip from banging into the mast or shroud. What am I missing??

Also, when i bought my boat it had big powerline style insulators on the backstay. Did they use the backstay as an antenna? Is it suitable for VHF???

[Paul Elliott]

Originally Posted by jared

I was wondering why i dont see people mount their VHF antennas on the shroud spreader? It seems like a nice safe place from lightning and protected from jib torment. I would run insulated support(s) to keep the whip from banging into the mast or shroud. What am I missing??

Also, when i bought my boat it had big powerline style insulators on the backstay. Did they use the backstay as an antenna? Is it suitable for VHF???

The masthead is the tallest point, and has the least interfering metal stuff. It really is the best place for the VHF antenna. I have my AIS antenna on the upper spreader, and while it works well, there is probably some interaction with the mast and shrouds. If for some reason you can't put the VHF antenna on the masthead, the spreader is probably your best alternative.

In the event of a lightning strike, I doubt that the spreader location would give much protection.

The large insulators on the backstay are so it can be used for a SSB antenna (3-30 MHz). This would not be appropriate for a VHF antenna.

[Wotname]

Originally Posted by jared

I was wondering why i dont see people mount their VHF antennas on the shroud spreader? It seems like a nice safe place from lightning and protected from jib torment. I would run insulated support(s) to keep the whip from banging into the mast or shroud. What am I missing??

Also, when i bought my boat it had big powerline style insulators on the backstay. Did they use the backstay as an antenna? Is it suitable for VHF???

Although Paul E's post suggested the backstay was not appropriate for VHF, let me emphasis this point.

An insulated backstay is not suitable for VHF; not as in never, no, not OK and wont work!

[Jim Cate]

Originally Posted by Wotname

Although Paul E's post suggested the backstay was not appropriate for VHF, let me emphasis this point.

An insulated backstay is not suitable for VHF; not as in never, no, not OK and wont work!

Yes, Geoff, but can I use it anyway???

Jim

[Wotname]

Originally Posted by Jim Cate

Yes, Geoff, but can I use it anyway???

Jim

How remiss of me!

I should have made my previous post more clear so please allow me to restate a more appropriate explanation.

Yes Jim, you can use the backstay for your VHF antenna; it will work for you quite well; however it won't work for Jared, nor for anyone else (including me). We are just not special enough...

It's all to do with RF propagation and who is special and who isn't. Look mate, it's going to easier to explain over a bottle of red when next you visit the sourthern isle

[Sailcraft]

Hi Jared,
Interesting post re AIS antenna position. As we are on a different boat every trip we have tried many positions. I found that being on or near the spreaders gave us many blind spots especially when a ship passed abeam with our mast between the antenna and the ship. Recently I have been mounting it on the taff rail sometimes on a broom stick for elevation and this seems to give us the best range. The best option for us is taping into the mast top VHF antenna. Hope this helps.