Mocom 70, Mitrex radio setup

[Kingsjourney]

So from my understanding as of now there would be no way to use these as simply a long range 2 way radio system between 2 ppl. I got a few of these from an auction. And was thinking maybe could use them for communications between me and someone else for private use. But from what I've read these can't be used in that way or registered or licensed for private use??? Is there a way to find out what frequency they are programmed too?

 

[KevinC]

Neither of them are "programmed". They both use channel elements (crystals) for each transmit and receive frequency.

Maybe you got lucky and they are all on the same simplex frequency that you could get licensed for. You'd have to pop the top of the drawer unit off and hope the frequencies are stamped on the elements and go from there.

 

[mmckenna]

There's some good info here:

Motorola Mitrek Model Numbers list

But, yeah, you need to know with 100% certainty what frequency they are on.

If you are in the U.S.A., there are a number of FCC regulations that will make it difficult or impossible to use these. One of the reasons they are on the auctions is that they are essentially useless to all but a very narrow group of users...
If they are VHF or UHF radios, then the only place they will be legal is on the amateur radio bands. That will require you and all other users to study for the FCC Amateur radio test, take the test and receive amateur radio licenses. It's highly unlikely these radios were used on amateur radio frequencies, so that means they'll need new channel elements and tuning. That won't be cheap or easy as the channel elements can be hard to come by.

If they are low band radios (30-50MHz), you can go through a frequency coordinator and see if you can get assigned the same frequency that is in the radios. Then you'll need to pay the FCC for a business/industrial license to use them

But, then again, these are -old- radios, and they'll no doubt be badly out of tune and it's entirely possible that capacitors have leaked and need replacement. Again, that'll be expensive and time consuming to rectify.

Hate to sound so negative, but there is a reason these radios are on the used market. You will have a hell of a time making them legal to use, and you may very well sink more money into them than if you had just purchased new radios from the get-go.

 

[RFI-EMI-GUY]

These frequencies are for itinerant use. Anyone with a business need may apply for them. They are wide band, 100W FM. Only need to pay FCC fees.

-----------------------
27.49 Base or Mobile 10.
35.04 Base or Mobile 10.
43.04 Base or mobile 17.

(10) This frequency will be assigned only to stations used in itinerant operations, except within 56 km (35 miles) of Detroit, Mich., where it may be assigned for either itinerant or permanent area operations (i.e., general use).

(17) This frequency will be assigned only to stations used in itinerant operations.
-------------------------

 

[com501]

-now wondering why I have a bin full of channel elements in the warehouse.....

 

[ElroyJetson]

Those radios date from the 1970s. Their reliability and quality is superb. They probably still work just fine.
But as for parts support....good luck.

I have heard of people homebrewing frequency synthesizer circuits for them so they aren't limited to the frequencies
on the channel elements in them. But that's a reasonably advanced project.

 

[RFI-EMI-GUY]

-now wondering why I have a bin full of channel elements in the warehouse.....

You should mine for the itinerants and ham in every band and resell the rest for recrystallizing.

 

[RFI-EMI-GUY]

Those radios date from the 1970s. Their reliability and quality is superb. They probably still work just fine.
But as for parts support....good luck.

I have heard of people homebrewing frequency synthesizer circuits for them so they aren't limited to the frequencies
on the channel elements in them. But that's a reasonably advanced project.

A lot of effort when you can find a nice Maratrak or a Syntor X9000 for cheap.

 

[ElroyJetson]

Sure. Lots of options are there if you want an obsolete but PC programmable radio.

The problem there is, today in 2021 it may be much easier to find the radio than find a working PC that is fully compatible and WILL reliably program it. The main reason I stopped trying to support really old Motorola programmable radios was the effort required to maintain the programming PC.

 

[RFI-EMI-GUY]

Sure. Lots of options are there if you want an obsolete but PC programmable radio.

The problem there is, today in 2021 it may be much easier to find the radio than find a working PC that is fully compatible and WILL reliably program it. The main reason I stopped trying to support really old Motorola programmable radios was the effort required to maintain the programming PC.

Sadly true. What is needed is a DOS emulator tailored to RSS software and serial communications. I was shocked to find that I had a power supply failure in one of my IBM PS2/E and hard drive in the other. These were identical computers main and back up set aside for RSS.

Even the plastic on the PS2/E is failing as it was a recyclable product back when introduced.

I am supporting Systems Saber radios and now have interest in Syntor X9000 low band. I guess for the former I could jump ahead and go APX, but then, will the required cloud services be around 5 years from now?

 

[ElroyJetson]

The Syntor X9000s and their suitcase programmable older brothers, the Syntor X, are still in my opinion the BEST mobile radios that were ever made. The range I got out of mine back when I was running one in my car was legendary. The VHF 110 watter's PA can be cranked up to about 225 watts of CLEAN RF power in a fixed installation if you run its supply lines at 18 volts out of a sufficient power supply, and 150 watts was usually achievable just with a simple adjustment while the radio was still in the the car. With that setup and its amazingly sensitive (and yet selective) receiver I was able to work simplex contacts at ranges usually reserved for repeater operation. And repeater operation...I could work repeaters over 100 miles away at full quieting both ways. The TX audio was amazingly clean without any audible background hum or noise.

The Spectras that followed them were nice radios but the Syntors were just BETTER in terms of real world performance. And Spectras had component failure problems I never saw in a Syntor.

 

[mmckenna]

There was a company called PIIEX that used to make an adapter you could plug into a Syntor X 9000 and program it via Windows XP. I had one as a base radio and it worked well. Scored it from the fire station at work when they upgraded.

SyntorX Flash Memory Upgrade - $109.00 : Piexx Company, Computers & Electronics

Piexx Company SyntorX Flash Memory Upgrade - Our Flash memory module replaces the original SyntorX memory module and allows you to easily download channel information into your transceiver from a PC running the Windows 9x, ME or XP operating system. All hardware and software is included with the...

www.piexx.com

 

[com501]

There was a company called PIIEX that used to make an adapter you could plug into a Syntor X 9000 and program it via Windows XP. I had one as a base radio and it worked well. Scored it from the fire station at work when they upgraded.

SyntorX Flash Memory Upgrade - $109.00 : Piexx Company, Computers & Electronics

Piexx Company SyntorX Flash Memory Upgrade - Our Flash memory module replaces the original SyntorX memory module and allows you to easily download channel information into your transceiver from a PC running the Windows 9x, ME or XP operating system. All hardware and software is included with the...

www.piexx.com

That was for the EEprom programmable Syntor X not the X9000.

 

[mmckenna]

That was for the EEprom programmable Syntor X not the X9000.

You are correct. Just shows you how long ago it was and how many brain cells I've lost in that span of time.

 

[WPXS472]

The Syntor X9000s and their suitcase programmable older brothers, the Syntor X, are still in my opinion the BEST mobile radios that were ever made. The range I got out of mine back when I was running one in my car was legendary. The VHF 110 watter's PA can be cranked up to about 225 watts of CLEAN RF power in a fixed installation if you run its supply lines at 18 volts out of a sufficient power supply, and 150 watts was usually achievable just with a simple adjustment while the radio was still in the the car. With that setup and its amazingly sensitive (and yet selective) receiver I was able to work simplex contacts at ranges usually reserved for repeater operation. And repeater operation...I could work repeaters over 100 miles away at full quieting both ways. The TX audio was amazingly clean without any audible background hum or noise.

The Spectras that followed them were nice radios but the Syntors were just BETTER in terms of real world performance. And Spectras had component failure problems I never saw in a Syntor.

In a former life, I worked in a government radio shop for a few years. While there, we installed and maintained a fleet of about 150 VHF X9000s. About the only real issues were with the outboard Securenet box dropping the key when a truck carrying one ran over a bump. Before I left, we were getting failures with the vacuum florescent displays in the control heads. They were discontinued while I was there, and we put in our first Spectra. I understand they are now on a low split UHF trunked system, contractor maintained. The X9000 was a well made radio.

 

[ElroyJetson]

Yeah, the infamous "physical security housing", with Medeco high security keys. Those housings had a tamper switch in them, (Omron microswitch, as I remember) and if that switch activated due to tampering (or enough vibration) then it'd erase the key. Or so says my not necessarily perfect memory.

I got two of the older Syntor (original, pre-X) radios from the local base surplus auction for a song. UHF low band, of course, and totally useless other than for listening to base security when in range. (They had but never used encryption.) They were complete with PSHs and even had the keys. I did have fun learning all about them but their UHF low split made them basically useless for any other purpose.

 

[WPXS472]

Yeah, the infamous "physical security housing", with Medeco high security keys. Those housings had a tamper switch in them, (Omron microswitch, as I remember) and if that switch activated due to tampering (or enough vibration) then it'd erase the key. Or so says my not necessarily perfect memory.

I got two of the older Syntor (original, pre-X) radios from the local base surplus auction for a song. UHF low band, of course, and totally useless other than for listening to base security when in range. (They had but never used encryption.) They were complete with PSHs and even had the keys. I did have fun learning all about them but their UHF low split made them basically useless for any other purpose.

Ah yes, low band UHF. We had some while I was there, but mostly low split VHF, and some high split VHF. The Mitrek the OP mentioned was, in my opinion, a great radio. Just kept on working. I bought about 20 at the local DRMO auction, and about had to give them away. No one wanted to fool with re crystalling channel elements.

 

[RFI-EMI-GUY]

Yeah, the infamous "physical security housing", with Medeco high security keys. Those housings had a tamper switch in them, (Omron microswitch, as I remember) and if that switch activated due to tampering (or enough vibration) then it'd erase the key. Or so says my not necessarily perfect memory.

I got two of the older Syntor (original, pre-X) radios from the local base surplus auction for a song. UHF low band, of course, and totally useless other than for listening to base security when in range. (They had but never used encryption.) They were complete with PSHs and even had the keys. I did have fun learning all about them but their UHF low split made them basically useless for any other purpose.

I found it curious that nearly every time I see one of those boxes surplused it has with it the security keys. Did any agency actually pull those from the vehicles and put them in a vault? Maybe it was too burdensome a procedure.

I would love to get a schematic for those boxes because that are dirt cheap and could be used to add encryption to a suitable modern radio or repeater.

 

[ElroyJetson]

Just obtain the Systems 90 master wiring diagram (It's got to be out there...) and it'll pretty much tell you exactly what wires are important.

Once I had that diagram, I studied it and soon understood how to use it. At that point, adding any Systems 90 modules became a breeze, provided I had the proper pin installation/removal tool.

 

[RFI-EMI-GUY]

Just obtain the Systems 90 master wiring diagram (It's got to be out there...) and it'll pretty much tell you exactly what wires are important.

Once I had that diagram, I studied it and soon understood how to use it. At that point, adding any Systems 90 modules became a breeze, provided I had the proper pin installation/removal tool.

Good advice. It will be just a few!