RG-8 to the masthead is pretty much a standard rig for masthead antennas and
if the connectors are well done the signal loss is acceptable. The benefit
of the additional height far and away overrides any signal loss. Try to make
the antenna cable in a single run from the masthead to the back of the
radio - no through-deck connectors.

If you don't want to run cable of that diameter, don't try for the masthead
because the loss in the smaller cable over a run of that length would be
pretty bad.

Tom Dacon

" Mika" wrote in message
...

Need to install a new VHF antenna to a sailboat. Masthead would give
max antenna height, but drawback would be longer cable and extra
connectors. Have some experience about cable and connector losses
being a ham radio operator, and therefore give serious thought to
putting the antenna to top a a short pole on deck. Shorter cable, no
need for extra connectors as this would be permanent installation.
Plus much easier to install.

Lower antenna height (some 3-4 meters instead of 14m in masthead
installations) will of course reduce range, but would it stll be ok
for costal waters. In my home waters some 20 NM range is quit enough
to contact coastguard or SAR if needed.

Mika

On Tue, 16 Aug 2005 14:57:34 -0700, "Tom Dacon"
wrote:

RG-8 to the masthead is pretty much a standard rig for masthead antennas and
if the connectors are well done the signal loss is acceptable. The benefit
of the additional height far and away overrides any signal loss. Try to make
the antenna cable in a single run from the masthead to the back of the
radio - no through-deck connectors.

If you don't want to run cable of that diameter, don't try for the masthead
because the loss in the smaller cable over a run of that length would be
pretty bad.


agreed. some folks have recommended rg 58 which has all the bad
characteristics and none of the good ones of proper coax.

---------------------------
to see who "wf3h" is, go to "qrz.com"
and enter 'wf3h' in the field

I have just seen a range of low-loss thin ad flexible 50 ohm coax -
aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be,
i would be great for use on boats for both HF and VHF. Has anyone used
it?

wrote:
I have just seen a range of low-loss thin ad flexible 50 ohm coax -
aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be,
i would be great for use on boats for both HF and VHF. Has anyone used
it?


Yup, great stuff. Not as flexible and thin as RG-58, but a lot more than
RG-213 (?).

I run a combination GSM/VHF/FM antenna at 20m high, 30m cable. The range
and clarity on VHF improved a lot when I swapped from my old antenna +
RG-58 cable. At sea, range is about 60 +- 20 km. Cell phone range (900
MHz) is about 60% more than using a hand-held cell phone (eg. about
10-15 km). This means that during coastal hops we're now in (GSM)
coverage all the time.

Tip: if you sail around on the North Sea, check out cell phone coverage
near Norwegian oil rigs; they seem to have Telenor transmitters ;-)

Regards,
Kees

I have just seen a range of low-loss thin ad flexible 50 ohm coax -
aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be,
i would be great for use on boats for both HF and VHF. Has anyone used
it?


Yup, great stuff. Not as flexible and thin as RG-58, but a lot more than
RG-213 (?).

As an installer and repairman, we used foam dielectric coax once in a while
for cell phone antennas because of UHF loss problems. It isn't as durable as
RG-213 (the standard for most installations around salt water, as it crushes
and flattens easier than solid dielectric.

There were some brands of foam dielectric coax that absorbed moisture that
degrades coax very quickly.

RG-58 is ok for short runs of 25 watt VHF, but in tall masts, it just
doesn't cut it. Also, it is a little light weight for 100 watt plus HF
installations.

The obvious weak link in most masthead installations is in the PL-259 coax
connector installation. There are not many out there who can do a proper,
watertight soldering job up at the top of a wavering, windy masthead. Been
there, done that, was not always proud of my work.

Old Chief Lynn, W7LTQ, PG-13-20604