Re: Motorola VRM-850 Digital Capable Radio – Black Friday Sale

Lillian W.

Here’s some tidbits I’ve learned from working with these over the years.


You can completely remove the modem control head and pop a Model 1 head on in its place. Zone/channel names won’t display correctly and the programmable buttons won’t work but it will give you a mic port and internal speaker (you have to bridge pins 1 and 2 on the 25 pin connector to enable) for testing as well as a functional power button. I have also encountered some of these in the wild that had an inactivity power off setting programmed into the modem head (which uses its own RSS) and swapping the modem head for a regular MCS head will fix this. Full and complete Model 1 800 MHz radios can usually be found on Ebay for cheaper than a Model II head by itself, and Model 1 heads don’t require dashmount mating plastic and will work as direct swaps for the modem head.


40W UHF radios also don’t like being programmed below 20W TPO and will run hot and eventually burn up if you try.


All of the VRM info is also applicable to any MCS2000 radio (they all have the VRM100 option available in CPS) so anything you can do with these you can also do with a VHF radio, R-split (403-470) UHF radio, or even 900 MHz radios.



Lillian KD5QCZ



From: [] On Behalf Of Steve N4IRS
Sent: Thursday, 25 November, 2021 10:29
Subject: Re: [DVSwitch] Motorola VRM-850 Digital Capable Radio – Black Friday Sale


About 5 years old, but still good info.

Steve N4IRS

On 11/25/21 11:22 AM, Skyler Fennell wrote:

Hi all, I have some Motorola VRM-850 radios available on sale for Black Friday. These are single channel data radios capable of running all digital modes if you wire it up to a board like the repeater builder STM32DVM.

They are $75 through Monday or until I run out of stock. The radios are capable of running between 440-450 MHz and I will program the channel in for you. I will include a little instruction sheet for wiring up to the MMDVM boards.

More info here:


Skyler W0SKY


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