Doug, it's difficult to generalize but in many cases the radiation
resistance of a whip will be in the range of 20 to 35 ohms (assuming the
whip is a quarter-wave or somewhat shorter) and the ground resistance in
series with that may be another 25 ohms or so. What you get is a
feedpoint impedance of about 45 to 60 ohms (could be more or less) which
will match 50 ohm coax very nicely without a tuner. Most transmitters
will feed loads of 25 to 100 ohms (2:1 swr) without complaining. For a
short run of coax, your total losses will probably be less than if you
used a tuner.

It is true that you can only use such an antenna for a single marine or
ham band. Even then, at the lower frequencies, you will experience a
limited band of frequencies that you can use without a tuner. On 8 MHz
and above, you will probably find that an antenna cut for the middle of
the band will cover the whole band nicely.

A lot of cruisers keep a 14 MHz "Hamstick" on board as an emergency
antenna they can use if their tuner fails or if (heaven forbid) they are
dis-masted and can't use their backstay antenna. In an emergency you can
check in to the Maritime Mobile Service Net on 14.300 MHz even if you're
not a ham. It is one of the few frequencies monitored almost
continuously by experienced operators. The Hamstick is easy to store,
easy to install, and once adjusted, should be trouble-free. To switch
bands, you switch Hamsticks. They even make a quick-connect gizmo.

There are other makes as well. But if you don't use something like a
Hamstick, and just use a longer whip like a 16 foot whip, it will be
good for just one band. Actually, 16 feet is close to a quarter-wave on
20 meters so you may be able to use it as-is without a tuner on that
band. If you're not comfortable doing the hookup, find a local ham to
advise you. They're usually glad to help.

Good luck!

Chuck


Doug Dotson wrote:
I believe that the ARRL patterns show the whip to be an unambiguously
better low-angle radiator than the backstay.


This might explain why I have had such good luck with a whip compared to
the backstay antenna I had on my previous boat.


But that's not all! The versatility of the backstay antenna at other
frequencies and the attendant complication of a tuner could be compared to
the simplicity of the whip, its physical independence from the mast, and
its lack of need for a tuner.


How do you get away without a tuner?

Doug
s/v Callista