Finch:

the best way to figure out what works best is try a bunch of different
configurations,
taking the car / SWR on a small test drive at the same timne of day ( Night) to
check each one out..

& then make notes, so you can accuratly compare each configuration &
subsequent performance

Dan


In article , "Finch"
writes:

Subject: More on that stupid auto SWR antenna.
From: "Finch"
Date: Thu, 15 Jul 2004 18:29:50 -0400

See my earlier post entitled mobile antenna if you care to but this is the
jist of of all.
Road trip. Want to listen to SW. Need antenna.

Ok, how about this, let me compromise.
My original idea was to take a bit of wire, attach it to the auto's external
antenna at the top
and fasten it with a wire tie. Run it down the length of the auto antenna
and secure it at
the base with another wire tie and run the free end in the window to connect
to the SWR.
It was said in this NG that this would produce too much electrical
interferance from the auto.

The next idea was to purchase a magnetically mounted antenna for the trip.
It was said in this NG that
due to too many electrical componants that it may not work well for SW
reception.
It may also get pulled off the auto by the wind generated by a large truck
or what have you.

Ok. New idea. Take the original thought. Fasten a length of wire to the
existing auto antenna at the top and
secure it with a wire tie. Run it down the antenna and secure it at the
base with another wire tie.
At this point cut it and solder on a coax with the antenna wire to the
center conductor of the coax. Solder another wire to the shield and run it
to ground. Run the coax in the window and connect to the short wave
receiver.

Well, what do you thing. Might work?

All comments welcome and thanks.

"Diverd4777" wrote in message
...

Finch:

the best way to figure out what works best is try a bunch of different
configurations,
taking the car / SWR on a small test drive at the same timne of day (
Night)
check each one out..

& then make notes, so you can accuratly compare each configuration &
subsequent performance


Hey Dan,
I agree with your approach. Research and trial and error are the best way
to really figure it out.
I like an experimant as well as the next person.
However, as my time is short, I had hoped to just get an answer as to what
is really best.
Your point is well taken.

Thanks and peace,

On Thu, 15 Jul 2004 19:41:14 -0400, "Finch" wrote:


"Diverd4777" wrote in message
...

Finch:

the best way to figure out what works best is try a bunch of different
configurations,
taking the car / SWR on a small test drive at the same timne of day (
Night)
check each one out..

& then make notes, so you can accuratly compare each configuration &
subsequent performance


Hey Dan,
I agree with your approach. Research and trial and error are the best way
to really figure it out.
I like an experimant as well as the next person.
However, as my time is short, I had hoped to just get an answer as to what
is really best.
Your point is well taken.

Thanks and peace,


Hi OM,

Your wire sharing the same length of car antenna is OK. However, use
insulated wire so that the two radios (yours and the wife's) don't
make their own arbitrary DC circuit (especially if you plan to power
your radio off the car's battery).

Further, your idea of using coax to go from the base of the car's
antenna back into the cab is fine. In fact extend that idea and
simple strip the coax cable down to its inner conductor and use THAT
to mount to the car antenna. Then you don't have to solder anything,
and you have insulated wire from the git-go and shielded wire back
into the cab. Make sure your coax shield doesn't accidentally touch
the car's antenna though. If this sounds like too thick a wire, use
RG-174 which is quite skinny (0.125" OD) and the inner conductor even
smaller. Wrap the inner conductor (or any wire arrangement) around
the car antenna at about one turn for every inch it climbs. This will
make for a loose spiral wrap, but give you a little more exposed
antenna for your set.

And yes. test. You don't want to drive 500 miles listening to the
spark plugs. If this happens, you may need to insure you find ground
for your set to actually turn that shield into something effective.
If that helps, but doesn't completely do the job, you may need to pass
the shielded lead through a ferrite core several times (RG-174 does
this great). If your hear alternator whine, you may need an
automotive power filter. Radio Shack sells them with big hurkin'
coils for big hurkin' current. Your radio will hardly need that much
current, so you can use larger (more inductance but less current
capacity) coils to more effectively suppress the whine.

73's
Richard Clark, KB7QHC