[Mobile-Portable] Iron Horse 40m Ground?

[Jay Eimer]

Guys,

Thanks for all your help - we got it!

Here's the solution.  The problem was the (lack of) ground through the
receiver hitch.  There's a bracket on the hitch for supporting the trailer
light wiring with a convenient 1/4" hole.  Through this I inserted a 1/4" SS
bolt w/washers on both sides, a ring connector and a lock washer and nut.  I
also put a star (toothed) washer under the flat washers to "dig in" to the
paint.  12 gauge stranded wire in the ring connector.  The other end is a
spade plug (female) on about 6" of wire.

This wire is then taped to the trailer light plug.

On the other end, I drilled a 5/32nds" hole in the Iron Horse mount, about
1" from the front (closest to the bumper when the hitch is mounted) and 1"
'in' (towards the ball) from where the coax pass through is mounted.  Same
as the other end with a #8 machine screw, washers, locks and nut.  This puts
it on the (roughly) 6" x 2" SS plate that makes the frame of the mount,
where the shield of the coax connects, and about 1" from it (keeps the screw
out of the way when removing - remember, this is a temporary antenna).  The
wire then runs down the hitch "shank", secured with tape (liberally) and
leaves a 6" or so pigtail with a spade plug (male) on the end.

We were getting the expected SWR fluctuations, weak signal reception, and
unreliable Tx.  I plugged in the extra ground, and signal levels jumped, SWR
went flat and stable (1.6:1 on 7.250, with about 90kHz range under 2:1) and
we made a contact (Century Club net) on the first call - 59 from Tulsa to
western Kentucky with no problem.

If I have to do this again, I think I'd use a better connector (PowerPoles,
maybe?).  And I'd buy better drill bits.  I'll say this for Iron Horse -
their mount was some HARD stainless!

Thanks again for the advice,
Jay
AD5PE

PS.  The spring is back - Bill insisted, but it's now a brand new one.

PPS.  Give a listen for him (KE5UL).  He's over 80 and had multiple heart
attacks and strokes, so he talks a little slow, but he's a great ham (former
Section Manager) that's been DXing for over 50 years.

-----Original Message-----
From: mobile-portable-bounces at mailman.qth.net
[mailto:mobile-portable-bounces at mailman.qth.net]On Behalf Of Tom Bates
Sent: Sunday, July 18, 2004 23:34
To: Mobile-Portable Reflector
Subject: Re: [Mobile-Portable] Iron Horse 40m Ground?


>>So I got out the antenna analyzer, and the needle was swinging all over
everywhere - seemed to be when the antenna was moving

Jay...  Sounds like the first thing to investigate would be the spring.  You
said "old", so mebbe corrosion or rust.  A quick test would be to make a
wire jumper with ring eye terminals to fit 3/8 studs on each end.  One end
under the spring, and the other on top of the spring.  These springs are
notorious for generating noise in the cheepie ones.  The better grade
springs have a wire braid going from end to end inside the spring.  Another
possibility is that the loading coil is just too close to the body of the
jeep.  Try swinging the bar farther away from the body to see if it has an
effect.

[snipped unrelated]