El 24-06-13 14:57, Kickin' Ass and Takin' Names escribió:


It's a long story, here's the short version.

Our volunteer rescue squad dispatch operates in the 152 - 154 MHz
range -- transmit on 154.XXX, receive 152.XXX.

Our main antenna barely survived contact with a tree limb and needs to
be replaced.

Our local Motorola sales rep has his head stuck firmly up his ass and
keeps trying to sell us some basic 1/4-wave verticals.

The current antenna is a vertical whip with a loading coil wound
along the length of the antenna.

The dimensions a

-- Overall height: 14.25 inches
-- 4 inches from the base the antenna is wound into a coil, about 3/8
inch diameter, 5 turns
-- the coil is 1.75 inches long
-- above the coil is 8.5 inches of antenna
-- NMO base

I suspect this antenna is an old model 5/8-wave VHF antenna, shortened
by winding a coil in the antenna.

If it is a 5.8-wave, it should be giving us a few dB gain. The
1/4-wave whip he wants me to install would give unity or less gain. In
our rural area, we need all the antenna help we can get. I an
thinking about installing a full-length 5/8-wave whip, but, we go into
a lot of driveways with low tree limbs and I doubt a full-length
antenna would survive very long.


I have Googled every term I can think of to find this antenna,
Motorola sales rep tells me he thinks its a "cellular antenna" . .
.which it clearly is not. My MFJ antenna analyzer shows a resonance
at 154 MHz.

Anyone help me identify this antenna?


- - - - -

Fat, Dumb, and Ugly
is no way to go through life.

But, if you're a
Republican,
you have no choice.


I agree with others. The full size quarter wave with correct size
radials will perform better then the current 14.25' stick, no matter
how you wind it.

Make sure you have some VSWR indication to tune it to your frequency
range, or just to check the complete installation.


--
Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM