Minitor frequency change

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MaxK98
Posts: 52
Joined: Thu Feb 02, 2012 8:24 am
What radios do you own?: Lots of Motorola!

Minitor frequency change

Post by MaxK98 »

Hi guys, quick question here. I am new to the Minitor 2 and I was wondering:

A couple of weeks ago I got a retired Minitor 2 from our fire department. They are pretty beat up but beside the speaker everything inside works fine.

Now today I acquired a literally brand new Minitor 2 SV from gov't surplus.

Normally I would have only changed the casing and top buttons but having the stored voice option would be cool.
Problem is, Our dept's minitor are UHF (410MHz) and the gov's minitor is VHF High (151MHz)

Both are 2 channels.

Could I only swap the "RF Board" (the detachable board with the crystals on it) ? It's seems too easy
I don't mind the 2 tone config, if everything works out fine I can also swap the filters and solder the required jumpers.

Thanks!
Lake Effect
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Joined: Tue Dec 06, 2005 9:47 am

Re: Minitor frequency change

Post by Lake Effect »

It can work. I did it several years ago going from U to V. Other than swap the RF board, there is a change in the antenna termination if memory serves correctly. Like I said, it has been a long time. I think it was on the main board end. I don't have the schematics with me this weekend to check it out.

L.E.
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MaxK98
Posts: 52
Joined: Thu Feb 02, 2012 8:24 am
What radios do you own?: Lots of Motorola!

Re: Minitor frequency change

Post by MaxK98 »

Anyone else know if it can safely be done?

Thanks
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MaxK98
Posts: 52
Joined: Thu Feb 02, 2012 8:24 am
What radios do you own?: Lots of Motorola!

Re: Minitor frequency change

Post by MaxK98 »

Ok so I made the swap and it seems to work fine so far.

Second question: I'd like to monitor 2 frequencies. My gov't surplus minitor is a 2 channel but the RF board that I swapped has only one crystal on it. I see 2 holes available to mount another crystal. I do have a crystal with the exact frequency (413 R 5125MHz) from another minitor but I am wondering if there is any tuning to do or it's gonna be fine if I just solder it there?

Thanks for the help
loband
Posts: 110
Joined: Fri Nov 25, 2005 7:29 pm
What radios do you own?: APX7500 plus too many to list

Re: Minitor frequency change

Post by loband »

You would also need the xtal tuning coil for the second freq if there is not one there already. Most likely it is not if it was a factory single channel. After the xtal and coil are installed, you would need to tune it on frequency with a communication service monitor.
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