Question Regarding Motorola Antenna

[abbylind]

Howdy
Does anyone have the specs or instructions on the Motorola elevated feed mobile UHF antenna?
They have a rigid shaft and a whip section on top (LAPD used them in the 80s)
Im trying to determine how the capacitor inside the base is tuned. I remember the small screw was removed and the capacitor (loading section) was moved and the screw was re-inserted in a different hole for a change in band width.
Anyone have any info on this antenna?

Thanks
Fowler
KC5AEE

[PETNRDX]

If you mean the 5 dB gain TLE6152B type I have the info.
This is not an elevated feed, but actually is a colinear. 'least that is what Motorola calls them.
Hopefully you have one of the versions that has the "bottom" coil that has either two holes or three holes.
The "top" coil is the same for all freq ranges, you just use a different hole (which makes it "rotate" in relation to the bottom coil.
The top coil has 5 holes.
If you think your antenna is from 450 to 512, you should have bottom coil one or three.
Both of those coils have the same physical look/dimension as the top coil, but holes in different locations.
Bottom coil type two has 1/4 of the outside "ring" cut off.
That is the coil from 406 to 430.
Let me know what coils you have and what range you want it to work at, and I will look up the screw locations on the charts.

[abbylind]

This coil has 5 holes in the top and one on the bottom. It looks like the bottom section has the quarter section missing, I was hoping for 440-470 Mhz Is it possible?

Thanks
Fowler

[PETNRDX]

Per the manual, that one is supposed to be for 430 and below.
Best thing is to try it.
Since there is only one hole in the bottom coil, you know which one to use there.
On the top coil, holding it so that the "cut" in the coil is at the top (say 12 oclock position) and the five holes are to the left, use the farthest left hole (that is number 5).
Hole 5 is at the 9 oclock position.
You might try moving the top rod section (if you can) and check with a wattmeter to see if you can get the SWR down.
The one you ideally wanted was the TAE6030B (with coil three, that has TWO holes in the bottom coil)
But I have found many of these that work good enuf.

[abbylind]

Thanks for the assist
I'll give it a shot

Fowler