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Help with commercial VHF mobile antenna
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. |
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