Interesting modified Motorola radios

Post by Pj » Thu Jan 26, 2006 11:21 pm

Anyone know of any interesting modified Motorola radios? Came across some stuff awhile ago, and just kind of curious to what companies have tweaked off the shelf radio's into doing.

Here are my two:

Modified Mitrek radio that was used in the Presidental Echo-Fox system:

Modified Spectras (Rockwell/GE Harris) used in locomotive DPU operations:

N4KVE · Post by **N4KVE** » Fri Jan 27, 2006 5:43 am

Funny thing. I noticed the freq 415.7 on the Mitrek. Whenever Air Force 1 came to town, I would hear very interesting phone calls on that freq. Not from the big man himself, but any non important phone calls from any guests on the plane. Brought back old memories.

73's to all. GARY N4KVE

wa2zdy · Post by **wa2zdy** » Fri Jan 27, 2006 6:23 am

Looking at that E-Systems tag brings back a memory or two. I know a guy who worked there. Saw the place once - HUGE. I think the factory is bigger than the rest of Greenville.

E-Systems also had a site in the Sinai years and years ago. I worked a guy once who was a contractor there for E-Systems. I recall him telling me he couldn't discuss his work!

apco25 · Post by **apco25** » Fri Jan 27, 2006 8:15 am

The DPU units are mounted in the toilet cubbyhole?

kb0nly · Post by **kb0nly** » Fri Jan 27, 2006 8:53 am

The Echo-Fox Mitrek is what everyone based the repeater mod off of for that radio. Easy to duplex!

So what is the Spectra's hanging on the wall used for?

NSPD · Post by **NSPD** » Fri Jan 27, 2006 9:59 am

apco25 wrote:The DPU units are mounted in the toilet cubbyhole?

That's on the other side of the nose..

k2hz · Post by **k2hz** » Fri Jan 27, 2006 11:36 am

kb0nly wrote:So what is the Spectra's hanging on the wall used for?

DPU Locotrol is a remote control system for locomotives (Distributed Power Units) located in the middle or rear of the train controlled from the head end locomotive. It operates on 452/457Mhz frequency pairs.

Some locomotives built for Locotrol operation have an extended short hood so there is plenty of room for the Locotrol equipment as well as the toilet compartment. Some Locotrol had the equipment in a special boxcar that connected to any locomtive with the regular MU jumpers.

motorola_otaku · Post by **motorola_otaku** » Mon Jan 30, 2006 12:37 pm

k2hz wrote:Some locomotives built for Locotrol operation have an extended short hood so there is plenty of room for the Locotrol equipment as well as the toilet compartment. Some Locotrol had the equipment in a special boxcar that connected to any locomtive with the regular MU jumpers.

Sounds like something Norfolk Southern would come up with. Got any pics?

Funny that they'd use Spectras and not, say, MCSs. Locotrol hasn't been around that long; since what, the late 90s? That's well within the MCS manufacturing window and still late enough to be towards the end of the Spectra window.

NSPD · Post by **NSPD** » Mon Jan 30, 2006 12:45 pm

Locotrol has been around since at least the mid-1980's. Canadian Pacific and Southern Railway (later Norfolk Southern) were big users of the radio-control boxcars. The advanatge of those cars was that you could couple/MU them to any locomotive set and you instantly have radio control without having to install Locotrol equipment on every unit.

http://sunny16.photo.tntech.edu/~richar ... 905977.jpg
NS (ex-SR) Radio Control Car

Josh · Post by **Josh** » Mon Jan 30, 2006 5:16 pm

Many of the UHF Spectras in use have 1998 manufacture date codes on them... well into the Astro Spectra manufacture window

-Josh

jistabout · Post by **jistabout** » Tue Feb 07, 2006 11:05 pm

As far as I know, I was the originator of the Mitrek mod which uses techniques similar to the Echo-Fox mods, but using "N" connectors instead, with the rx connector replacing the Lock, etc.

An article by Mike Morris on Repeater-Builder has a pic of my original modded radio (from 6-7yrs. ago) and a discussion about it. I think there's another article somewhere that shows a variation on it.

Back then, I chose to put both antenna connectors on the front of the radio as was done on the Echo-Fox radios because I didn't need the lock, and didn't really like the idea of anything sticking out of the sides. I replaced the internal tx cable with small double-shielded cable, and left the rx cable as-is. Was worried on that first one about desense but no problem whatsoever.

I've done several Mitreks that way in years since and they are all still working fine as repeaters as far as I know. That original discussed above was sold on eBay a couple of times over the years and I think once on eHam or some other ham board and then I lost track of it.