Lo Band Motorola Base Antenae ???

[Satelite]

Hello everyone:
I have a Motorola Lo Band fiberglass base station antenae.
Im trying to read the model number off of it and believe its .
M/N = TOS-6073 I think but the S might actualy be a 5.
Known freq it was on for sure was 35.180 mhz.
Anyone know the exact freq spread it will do and the length the top fiber glass whip should be (Its broken off)
It threads into the bottom part of the antenaes first fiber glass mast just as the old cb base antenaes known as the Big Stick.
Anyone know what the db gain might be ect ?
Im wondering if i could put a CB fiber glass 102 inch on it and trim to length for use in the 42 to 50 mhz area by chance.
What do i have for an atenae and its specs and what are my options here with its use.
Thank you
Satelite

[Will]

Those were made by Phelps Dodge for Motorola.

They are very narrow on the frequency, usally less than 100KHz.
The "cb" whip may work if you find the correct lenth, about 1/4 wavelenth. There is an impeadance matching section inside the base and the lower half of the dipole is inside the fiberglass.

[Satelite]

Hello again:
Ok back to this base antenae.
Im in the process of attempting to replace the top whip on this antenna.
Its exact known freq from the factory was 35.180 mhz.
And Will has identified it as a Phelpd Dodge TOS-6703 made for motorola.
Anyone know its legnth the top whip should be for 35.180 mhz ?
What is the 1/4 wave formula for calculating a 35.180 mhz legnth ?
Actualy i may have located the 1/4 wave formular.
Would the length for a 1/4 wave be 79.81 inches long for 35.180 mhz ?
Thank you
Satelite

[N0SIH]

Yeah Satelite. Your figure is the same I calculated in inches from an altered HAM utility I use for building antennas. As you say an old CB antenna could easily be tuned for the frequency you are using. An MFJ-259 antenna analyzer is one of the handiest items I have in my arsenal of equipment. 73 de Jeff/N0SIH

[N0SIH]

One other thing Satelite, per your formula you should see that the length for the antenna in your desired bands would be from 56 to 62 + or- inches. My rule of thumb is the higher the frequency the shorter the antenna. (but you knew that)
Being able to edit a post would be a nice feature too. 73 de Jeff/N0SIH

[Will]

Actualy i may have located the 1/4 wave formula.
Would the length for a 1/4 wave be 79.81 inches long for 35.180 mhz ?
Thank you
Satelite

That sounds about right, 1/4 wave in free space. Start a little long and check the VSWR. Use an antenna analyzer like the MFJ 269.

[Satelite]

Hello Again:
Anyone know what the maximum wattage this antenae was designed for ?
Im wanting to put a 60 watt maxtrac on it.
Will it handle that ok ?
Base antenae model number = TOS-6073 made by phelps dodge for motorola im told.
Satelite

[Will]

I am not exactly sure, but they were used on 330 watt paging stations. So 100 watts at resonance should not be any problem.