[Mobile-Portable] Iron Horse 40m Ground?

[Jay Eimer]

Okay, finally got back to Bill's and did some tests.  New spring, no
difference.  No spring, no difference.  Consensus is it's the ground
(intermittent through the receiver hitch).  I'm going to try rigging a large
gauge stranded wire with trailer lights style bullet plugs - one from a bolt
through a convenient hole in the hitch frame, and the other on a solder tab
on the SO-239 on the under side of the mount.  The reason for the bullet
plugs is that this hitch/antenna assembly must come off and on easily.  You
see, Bill is 80+ years old, and uses a walker and/or wheelchair to get
around.  We have to be able to open the hatch to get the chair out of the
back of the Jeep.  One bullet plug, one snap clip and clevis pin and the
hitch/antenna can be snaked around the side of the Jeep to clear the top
hinged rear hatch, then put back after its closed.

I'm still curious though about why this antenna is so picky about the
ground.  The Outbacker works fine, and the Iron Horse "hears" fine, but the
Iron Horse just won't get out.  I suspect the 706 is folding back due to
high SWR (although it's hard to say with the meter jumping all over
everywhere!)

I did test it with a temporary hard-wired ground, and it seemed to work
better.  Although, conditions were so bad tonight we still had trouble
making a contact.

Any OTHER ideas?

Thanks again,
Jay
AD5PE


-----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 stuff]