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I hope that all has been well with you. Over the
last two weeks I ran some
tests on the AM-1000 (different types of antennas + ground radials). I
thought you might be interested in what I came up with.
All of my tests were conducted with an AM-1000 mounted on a 36' push
up mast. The AM-1000 was grounded to the top of the mast and the mast
was grounded to an 8' copper ground rod. I won't drag you through all
the tests but share with you the highlights and any other information that
I think is relevant.
1) The absolute best antenna to use with the AM-1000 when it is mounted
on a push up mast (not to exceed 36') was the "PRO-AM" VALOR 160
Meter Mobile antenna (PHF-160)($79.95 @ Ham Radio Outlet) website
The PHF-160 provided a 6db gain over the standard full length CB SS
whip. That is equivalent to 1 S-Unit ... a significant gain. The PHF-160
tuned on the top jumper of the coil select jumpers so your matching
network is almost out of Z for this antenna. That is why it won't tune
if the mast is longer than 36 feet.
I would suggest that anyone using this antenna modify the 3/8-24
threads at the base of the antenna. The stud is brass and it cannot
hold the weight of the antenna (mine broke off on me). I drilled a
a hole in the base of the antenna (has set screws - comes off). If you
drill it from the other end (antenna shaft end ... there is already a
center to use for your tap drill. Drill through with a #Q drill then
tap the hole with a 3/8-24 tap. I screwed a steel 3/8-24 set screw
into the new hole then used lock-tite to keep it from coming out. After
the lock-tite dried I screwed the antenna into the 3/8-24 mount on the
AM-1000 and didn't have any more weight loading problems. Extend
the whip out all the way and tighten it with the small set screws. The
set screws are fragile so don't over tighten it.
When mounted on a pole with the AM-1000 grounded to the pole
adding ground radials made no difference. However if the AM-1000
was not grounded to the pole the ground radials made a difference.
My continually loaded 9ft copper pipe antenna (3024 turns - 600 feet
of #26 enamel coated wire) didn't work any better than a standard
full length SS CB whip.
Whips either SS or Fiberglass that were shorter than the full length
CB SS whip seemed to work as good as the full length one.
Anyway Keith ... that is what I found. I hope some of this information
helps you or your Customers. BTW ... I received the audio amp and I'll
test it next week.
The PRO-AM PHF-160 (160 Meter Mobile Antenna) - the absolute
best antenna to use below 36' with the AM-1000