Hey there, Doug,

I guess I took your question of

How do you get away without a tuner?

too literally! Obviously you've been doing it for years.

73,

Chuck


Doug Dotson wrote:
Comments below.

"Chuck" wrote in message
link.net...

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.


Agreed.


It is true that you can only use such an antenna for a single marine or
ham band.


And as such is an inconvenient situation on a boat.


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.


SOP for single band antennas unless one is interested in only a subsection
of the band in which case one cuts it for the center of the segment of
interest.


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.


I have Hamsticks for 80, 40, 20, and 15M. They were my only antennas
for a long time before I insulated the backstay and got an SGC auto
tuner. I still hang on to the Hamsticks as backups though. When I got
another boat that already had a 23' whip, I found that it worked better
than the backstay on my previous boat, so I have stuck with it.


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.


I have been checking into the MMSN for years now. Actually, the MMSN
is only in operation during certain hours (1200 to 2000 Eastern time). Other
nets are in operation during other hours (Coast Guard Net, InterCon, etc) In
an emergency you can check into anything anywhere.


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.


Been using them for years.


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.


I am a local ham I help myself alot


Good luck!


Thanks!
Doug, k3qt
s/v Callista