Sorry Chuck, but with frequency modulation (used with marine VHF
radios), the 'loudness' of a received signal has *nothing to do* with
the transmitter's power output or quality of the antenna system. Asking
"can you hear me now?" of a fellow mariner in the same harbor seems a
dubious way of checking the integrity of a vital communications system.
The most likely failure mechanism for an 'old' coax is water migration
into the cable - which generally happens at the antenna connection.
This *will* change the impedance of the cable, which *will* show up on
the thruline, or VSWR meter. "Old coax" in and of itself usually
doesn't "become lossy" simply becuase of it's age; 100 year old copper
conducts just as freely as 'new' copper.

MW

chuck wrote:
I don't think Roger is too interested in measurements, though, and
there is a lot of wisdom in the notion that if you want to know if
your big VHF is louder than your handheld VHF, the best way to find out
is to see if it IS louder. ;-)

wrote:
Sorry Chuck, but with frequency modulation (used with marine VHF
radios), the 'loudness' of a received signal has *nothing to do* with
the transmitter's power output or quality of the antenna system. Asking
"can you hear me now?" of a fellow mariner in the same harbor seems a
dubious way of checking the integrity of a vital communications system.

Disagree, Mike. My recommendation was
that the squelch be turned down so that
hiss could be heard. FM carriers of
different strengths will differ in the
amount of quieting they produce. It's
pretty intuitive. Even with the squelch
on, weaker signals may not break the
squelch. You're probably thinking of the
limiter function in an FM receiver which
irons out changes in amplitude from the
modulation. But that's not involved in
the weak signal test I suggested.

But I sure agree that "can you hear me
now?" won't do it.

Remember the objective as you yourself
correctly stated it: looking for more
range than the handheld (or,is the Quest
louder than the handheld). With the
squelch down and a distant station
cooperating, I see no reason a simple
and positive comparison of the two
radios can't be made.

Regarding coax, usually there is no
deterioration of the copper itself,
although braids are sometimes eaten away
in a marine environment. What happens is
that the dielectric changes as it
becomes contaminated. Measure the
capacitance of a piece of coax that's
been in a boat for ten years. Additional
shunt capacitance will attenuate
signals. Measure the leakage resistance
between the center conductor and the
braid and compare that to a new cable.

Many sailboats have coax connectors in
or near the bilge at the base of the
mast to facilitate dismasting, and these
connectors tend to be contaminated after
many years.

Chuck

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wrote:
Sorry Chuck, but with frequency modulation (used with marine VHF
radios), the 'loudness' of a received signal has *nothing to do* with
the transmitter's power output or quality of the antenna system. Asking
"can you hear me now?" of a fellow mariner in the same harbor seems a
dubious way of checking the integrity of a vital communications system.
The most likely failure mechanism for an 'old' coax is water migration
into the cable - which generally happens at the antenna connection.
This *will* change the impedance of the cable, which *will* show up on
the thruline, or VSWR meter. "Old coax" in and of itself usually
doesn't "become lossy" simply becuase of it's age; 100 year old copper
conducts just as freely as 'new' copper.

MW

chuck wrote:
I don't think Roger is too interested in measurements, though, and
there is a lot of wisdom in the notion that if you want to know if
your big VHF is louder than your handheld VHF, the best way to find out
is to see if it IS louder. ;-)

I agree with MW, even pick a few marinas at nearby ports and see how
far away you can hail them from! It just sounds like from a time
standpoint, you could get a simple answer this way the fastest.
Assuming all works acceptable, after the cruise, break out the meters
and get technical. A lot of these users have great ideas for you.