Testing Channel Elements

[yardbirdjr]

Hello!

I was curious if there was a way to test and determine the frequency of channel elements.

What I have is a large assortment of misc. channel elements.

Mostly Mitrek, Micor, Mocom-70, MT-500 and MX.

Most of the labels have been worn off or were never on the elements when I received them.

Like I said I was wanting to know if there was a way to determine the frequencies, without putting them in a radio to find out.

Please PM me with responses

Thanks in advance

David

[fineshot1]

Unless you have some sort of test jig from motorola that I do
not know of the only way that I know of to test them is in the
radio they were designed for. As far as determining the frequency
read the Khz on the crystal itself and use the models crystal calculation
mathmatics to determine the channel frequency. You can find the calculation
in the models service manual.

[yardbirdjr]

Ok

Thanks

David

[YetAnotherMotoUser]

Some times you don't need the radios...
Years ago when I had a large number of Motrac / Motran / Mocom-70 / Micor elements I took advantage of the fact that they all used the same pin diameter and all were 9.6 volt powered units.
The radio manual provided the pinout, or you can look up channel elements on www.repeater-builder.com
The pin diameter was roughly the same as #10 or #12 or #14 house wire (I forget which), so I cut three 3" long pieces and soldered the leads from a 9 volt battery clip to two of them.
An oscilloscope connected to ground and the 3rd pin told me if the element was outputting anything, and a frequency counter connected in parallel with the scope gave the the frequency.
I had made some notes about the IF frequencies and the multipliers from the radio manuals, so I was able to identify the channels from the frequency counter readings.
A P-Touch labeler took care of labeling the elements. The labeler took more time than testing the element.