MOCOM 70/Motrac/Private Line For Display/Installation

[RailroadMan]

Hello- I'm new. Just retired from the Railroad after 36 years. Since the 70's always had an interest in radio communications (scanners), was into the CB craze, and just recently with retirement got back into scanners. I'm not techno proficient. I'm restoring 2 old Firetrucks, and the MOCOM 70/Motrac/Private Line radio heads and old school Motorola metal speakers are period correct and set off the cabs nicely. Trying to install/wire the radio heads so at a minimum the red/blue/green pilot lights would light up; even better would be to be able to talk between the 2 trucks on the vintage equipment. I purchased some surplus "power packs' (for want of a better word) off Ebay from agencies that abandoned this technology/frequencies for digital and trunking. I don't have the technology or meters or tools to determine what frequencies are on these power packs. No desire to break any laws, just want to have the real deal in the cab for display at the Firetruck Musters and be able to use them on the way there. The power packs were from Indiana and Louisianna and I live in New Jersey, so I doubt there would be any agencies/companies using the same channel. Any help or advice would be greatly appreciated, and I would certainly pay for an installation. Thank you.

 

[impalass427]

For a start, to get the green/red control head lights to work even without the radio chassis , all you need to do is to apply 12volts + to pins 19 and 20 and ground the control head. The pin 19 was to power the receiver in the radio and pin 20 was for the transmitter. The green light will come on with the power switch and the red will light when you key the mic as long as the bulbs are good. Don S

 

[RailroadMan]

Motorola Forum

Thank you Impalass427

 

[K4EET]

<snip> Trying to install/wire the radio heads so at a minimum the red/blue/green pilot lights would light up; even better would be to be able to talk between the 2 trucks on the vintage equipment.

Talking between the 2 trucks with the original radio equipment will not be possible unless you have a Title 47 Code of Federal Regulations (CFR) Part 90 license, PRIVATE LAND MOBILE RADIO SERVICES, (https://www.law.cornell.edu/cfr/text/47/part-90) and place those radios on your assigned frequency(ies).

I purchased some surplus "power packs' (for want of a better word) off Ebay from agencies that abandoned this technology/frequencies for digital and trunking. I don't have the technology or meters or tools to determine what frequencies are on these power packs. No desire to break any laws, just want to have the real deal in the cab for display at the Firetruck Musters and be able to use them on the way there. The power packs were from Indiana and Louisianna and I live in New Jersey, so I doubt there would be any agencies/companies using the same channel. <snip>

Without complete model numbers of what you purchased, there is no way to know what frequency band the radios are in, whether they are conventional or trunking radios, etc. More importantly, just because the radios came from IN and LA and you are in NJ, that does NOT mean that you would not interfere with a user licensed to use whatever frequency those radios are on; if it were legal to begin with to transmit without a license to begin with (which it is not).

Your best bet is just to wire up the control heads so that the lights illuminate...

Finally, I want to mention: Welcome to Radio Reference! We will do the best we can to help steer you in the right direction to keep you in-check with the Federal Communications Commission (FCC) and answer whatever questions you might have.

Cheers! Dave

 

[RailroadMan]

Thank you

Thank you for the information Dave

 

[K4EET]

Thank you for the information Dave

You are very welcome. Out of curiosity, would you want to give us the model number info on your radios? Then we could tell you what type of radios you have...

Cheers! Dave

 

[zz0468]

It wouldn't be difficult to wire the microphone and speaker to something like an FRS radio so you could talk back and forth. It would take someone with radio skills to do it right, though.

 

[RailroadMan]

It says MOCOM 70 in big letters. I need my magnifying glass (which i misplaced)to see the other numbers LOL man, are they small!

 

[RailroadMan]

MOCOM 70

It wouldn't be difficult to wire the microphone and speaker to something like an FRS radio so you could talk back and forth. It would take someone with radio skills to do it right, though.

Thank you for the info!

 

[impalass427]

We need the model number on the radio chassis ( the box that goes in the trunk) not the control head

 

[RailroadMan]

Roger. Understood. I lost my mag glass. The only one isee clearly is MOCOM 70, which is ALSO on the trunk part

 

[K4EET]

RailroadMan,

The Mocom 70 model number should resemble this:

U73BBA1900A

unless Motorola changed the numbering scheme along the way.

Cheers! Dave

 

[K4EET]

On another note, have you looked at the Warren County, New Jersey Frequency Database here on Radio Reference? It is found at this web address:

https://www.radioreference.com/apps/db/?ctid=1791

It looks like Fire & EMS Dispatch is on 159.180 MHz. Can you verify that? If you can, I might have an idea for you...

Let me know. Dave

 

[RailroadMan]

Motorola Forum

Roger Dave thank you. Yes I monitor that on my Realistic PRO-2001. It is Warren County Dispatcher for Fire and EMS

 

[K4EET]

RailroadMan,

Well here is what I was thinking. If, and that is a big IF, your radios just happen to be compatible with the Warren County Dispatcher for Fire and EMS frequency, perhaps you could have a local Motorola shop program those radios for RECEIVE ONLY on that frequency. Then for parades, with the output of that receiver to a Public Address (PA) System on the truck, you would have real Fire & EMS communications radiating from the truck for parades. Now you might need a letter from Warren County authorizing the Motorola shop to do the programming; again in a receive only configuration. I know that many Motorola radios had that capability (for a receive only configuration) but I do not know if your radio model does. Anyway, this is just an idea for you to consider.

Cheers! Dave

 

[zz0468]

...perhaps you could have a local Motorola shop program those radios for RECEIVE ONLY on that frequency.

The Mocom 70 is not programmable. A frequency change requires crystals, which are becoming unobtainium.

 

[K4EET]

zz0468,

Ahhh... Thanks for the info/clarification... I didn't consider that aspect. Well then... There might be a possibility of doing what I suggested with a little detective work at radio shops and on eBay for the right crystals. LOL! :lol:

Cheers! Dave

 

[NVAGVUP]

Here is a news flash. Mocom 70 is not narrowband capable. No way now how. Even if you lower the deviation to 2.5 KHZ, it is not FCC type accepted for narrowband.

It is for demo purposes. If you want RX audio,(Assuming the dept is still using the same freq), pull all of the TX Channel elements and you get what you get. This radio is not allowed to transmit on Rule 90 FCC channels.

I cut my teeth on this radio way back when. Solid radio. If it is great shape, it would be cool to show a little history. Just no RF transmit from it.

 

[RailroadMan]

That is a great idea, many thanks Dave. I have been "off the air". Thanks for you ingenuity! Paul t

 

[K4EET]

That is a great idea, many thanks Dave. I have been "off the air". Thanks for you ingenuity! Paul t

Paul, have you found a magnifying glass yet to read those model numbers? Or maybe ask a neighborhood kid to read them for you... LOL! :lol: Cheers! Dave