Optimizing SSB Bacstay Antenna

[cburger]

I am getting ready to install a new backstay and I have been told it is important to have the correct length between the insulators to optimize the performance of the SSB marine radio for a particular band range. Would like to know if this is accurate and if so what band width would be the most important range to set the antenna up for and what length between insulators would be optimum?

[btrayfors]

Shorter lengths favor the higher bands (e.g., 12mHz and above) while longer lengths favor the lower bands (8mHz and below).

Which bands are of most interest depends on where you're sailing and what you intend. For most coastal, Bahamas, and Caribbean cruisers the bands of most interest are the 6, 8, and 12mHz marine bands.

On a Westsail 32 your options will be limited, since it would be hard to put up a 50 or 60 foot antenna for the lower bands.

Remember that the antenna starts AT THE TUNER, so the feedline length is included in the total length of the antenna. Anything over 23' or so will tune on all bands.

For most folks, a total length of 40-45' is a good compromise. That should be do-able on your boat, and will give decent performance.

The upper insulator needs to be about 2' or more from the top of the backstay. You don't necessarily have to install a lower insulator if you prefer to save some $$$ and to feed the antenna belowdecks at the chainplate. This arrangement generally works very well.

Bill

[bobconnie]

Thanks for your info Bill, I learned something great! I always thought you had to have upper and lower insulators !! Boy I would have saved a big bunch of money if I had know this yrs ago LOL but really thanks

[btrayfors]

Originally Posted by bobconnie

Thanks for your info Bill, I learned something great! I always thought you had to have upper and lower insulators !! Boy I would have saved a big bunch of money if I had know this yrs ago LOL but really thanks

It works very well provided that you don't have a metal-hulled boat or a hydraulic backstay adjuster.

If you're worried about "RF burns" -- a much overblown danger IMHO -- you can always put a PVC sleeve on the lower end of the backstay.

Main advantage is that you don't need to pass the GTO-15 feedline thru a hole in the deck, don't need a long feedline running way above deck, and altogether you wind up with a more efficient antenna system.

Bill

[cburger]

Originally Posted by btrayfors

It works very well provided that you don't have a metal-hulled boat or a hydraulic backstay adjuster.

If you're worried about "RF burns" -- a much overblown danger IMHO -- you can always put a PVC sleeve on the lower end of the backstay.

Main advantage is that you don't need to pass the GTO-15 feedline thru a hole in the deck, don't need a long feedline running way above deck, and altogether you wind up with a more efficient antenna system.

Bill

Problem with this on a Westsail is backstay attaches to a metal crosspiece on the boomkin that is supported by stainless stays that can be submerged from time to time.

[btrayfors]

Originally Posted by cburger

Problem with this on a Westsail is backstay attaches to a metal crosspiece on the boomkin that is supported by stainless stays that can be submerged from time to time.

Bummer. Guess you're stuck with installing two insulators :-(

Bill