At 05:10 PM 12/27/07, you wrote: >Repeater-Builder Guru's, >I am trying to tune up the transmitter on one of my Mitrek's and am >having no luck and alot of frusteration.
And I guarantee you will ruin the PA deck (all it takes is one "click") unless you read the caution in my interfacing article about C800L and how to tune it. >I have the motorola manual and the cheat sheets here: >http://www.repeater-builder.com/mitrek/pix/mitrek-tx-tuning.gif > >The question is, what do I need to measure when they say, Meter position >3 (Which I understand is pin 3 on the test socket) On the lower numbered positions, yes, but not always. Some times it is a sequence of 21345 rather then 12345. The higher numbered ones get strange, and on the transmitter they float both ends to measure PA deck current. It can be a real pain to try and hold both probes in socket pins and tune an adjustment, and then swing a locknut on the peak. 90% of the time the adjustment creeps just a hair as the locknut binds. >but what do I need to measure with my multi-meter? >Milli-volts? >Milli-amps? >Micro-amps? 50 ua full scale. And don't even think of trying to use a DVM to tune a radio. You really need a needle type meter to see the peaks and dips. >Do I simply put my negative terminal for my multi-meter to ground, and >the other test lead to the appropriate pin? Or does my negative terminal >need to be in one of the test sockets? Look in the Test Set article on Repeater-builder (click on Motorola then test sets). You will find schematics of the test set and the cables. If you are going to do more than one radio then buy a greyface or silverface test set on ebay, you will thank yourself, especially when you are trying to hold two probes, a screwdriver and an open-end wrench. A friend one took a photo of me with a screwdriver in one hand, a wrench in the other, a test probe in my teeth, while keeping my eyes on a VOM, and his parrot on my shoulder looking down on it all. Not to be blunt - but if you can't afford a old Moto Test Set and a Motrac/Motran/Mocom/Mitrek cable, at least buy an old Simpson 260 or a Tripplet 630 and build a box with a test plug (you can gut a sealed relay that has the right plug) and a rotary switch to drive the meter. I went the cheap way in my early days and bought old 50ua meters for $5 to $10ea and burned up two of them by going across the wrong points on the test jacks. >Also, I have Mitrek Model HUE1159BPR radio, which is for 470-512. I am >trying to run it on 462/467, is that too far out of range for this radio? Only had three high range radios and used em all for parts or trading stock, so can't help you much. But figuring that a 450 radio will have acceptable receive performance down to at least 438.5, occasionally to 435, you should be OK. Transmitters stretch farther than receivers. >Any word of advice would be greatly appreciated. See above. Let us know how it works out. >Regards, > >Richard Bessey >KE7IOD Mike WA6ILQ
