1984 called... (EF Johnson)

[westcoaster]

1984 called,
They want their desk microphone back...

Bit of a fun thread looking at old junque...

What is an LTR radio any way?



Acquired these radios from someone cleaning out their garage.
Funny how a guy that grew up in the '80s considers that to be a reasonably "modern" time until one starts looking at the electronics from that era....




Next stop for these is electronics recycling...
If someone wants any part of these, pay for shipping and chip in a little extra for packaging and it's yours...

 

[kd4efm]

😂😂😂😂

 

[buddrousa]

It was a version of trunking that did not use the Motorola version of control channel data.

 

[mmckenna]

What is an LTR radio any way?

Logic Trunked Radio. EFJ developed it. As Budd said above, no common control channel. Used "home" channels for talk groups.
Pretty simple and works well. Still in use on some systems today.

 

[mikewazowski]

We’ve still got a few LTR sites in service. Very simple system which worked quite well.

 

[2IR473]

Those appear to be 800 mHz models. I used to do the mod for the 900 mHz EFJ radios that was offered by N2MCI and put them on the 33 cm amateur band. That was great since I could get those EFJ 8640 & 8655 radios for about $15 on eBay. Unfortunately, probably not much use for the radios you have there. If you want, you can swing by my place and take all the old EFJ Challenger mobiles I have here, to the recycling center as well.

 

[westcoaster]

Those appear to be 800 mHz models.

That explains the 800Mhz base antenna I tipped into the trash....

Funny the things we did before cell phones....

 

[MTS2000des]

EF Johnson deployed the first ClearChannel LTR system in 1980, this was at least two years before Motorola, Inc. released Privacy Plus.
There are still a few LTR and LTR Passport systems hanging on in 2022.
Ef Johnson

 

[westcoaster]

The finest in 1984 compact electronics...



I thought hinging the daughter? board was a novel idea.... Remove the three screws, flip up on the hinge to access the components below.
That one chip is the size of a school bus....

Name those components....

Radio measures 7.5" wide, 10" long and 2.5" high
Try and stuff that in a modern pickup....

 

[KevinC]

The finest in 1984 compact electronics...

View attachment 125988

I thought hinging the daughter? board was a novel idea.... Remove the three screws, flip up on the hinge to access the components below.
That one chip is the size of a school bus....

Name those components....

Radio measures 7.5" wide, 10" long and 2.5" high
Try and stuff that in a modern pickup....

View attachment 125989

Just add a Scorpion board and you're good to go.

 

[jeepsandradios]

Radio measures 7.5" wide, 10" long and 2.5" high
Try and stuff that in a modern pickup....

Not really much bigger than the newest MSI radio....

APX8500 Mid Power Radio Transceiver and O7 Control Head - Dash Mount 51 x 178 x 256 mm (2.0 x 7.0 x 10.1 in)

BTW...think I have a few of the mobiles in 800 multinet in barn from our old system. The Viking platform did LTR, Conventional or MultiNet depending on the controller. I think i also have a few LTR Trident Controllers in the barn...Miss that old stuff.

 

[Whiskey3JMC]

What is an LTR radio any way?

Logic Trunked Radio - The RadioReference Wiki

wiki.radioreference.com

Still numerous LTR systems in service in the Philly region. Mostly cabs, buses, etc who haven't migrated to DMR or NXDN

 

[mmckenna]

I think i also have a few LTR Trident Controllers in the barn...Miss that old stuff.

As of a few years ago, Trident was still selling LTR controllers. Might still be.
I almost bought one when it was time to replace my failing SmartNet system. Went NXDN instead, but would have been an inexpensive solution.

 

[jeepsandradios]

We installed many of the tridents before MSI started with LTR. The latest was the Raider Trident Controller. It did both LTR and community panel so was great to migrate customers from their own systems over to LTR. We eventually replaced them with Passport (also made by Trident). After I left the shop the owner dropped all his LMR stuff. Was a great UHF system but nextel and other stuff grabbed folks away.

 

[buddrousa]

In my small area we built over 15 sites

 

[wd8chl]

Yeah, quite a bit of LTR systems still on line, but I don't know of any on 800 MHz anymore. That's all taken over by P25 trunked systems.
If those aren't 900 MHz, I'd say forget it.

 

[fire_master_21]

Still have an 800 LTR in my area

 

[AM909]

Here in SoCal, we still have "a lot" of pretty much everything.

 

[n2mci]

I did take a 8600, same as 8604 pictured above, changed a bunch of SMD cap's and make it work on Ham 900mhz. The power was reduced
do to 800mhz optimized. Also 8600/04's are wide band vs 900mhz narrow band. This was more of an experiment to see if it would work.

I didn't swap the front end filter as it's a fair amount of work and I've already did that with big brother 8610/15. The 800mhz 8610/15's,
dispite being being 800mhz, have a fairly narrow band pass (about 2.5 kc sweat spot) and work well as a 900mhz ham rptr receiver.

The 8700 stuff is not of much use, other that parts.

Pete N2MCI

 

[KevinC]

Speaking of 8700’s. Those things were rock solid radios. About the only thing I ever replaced on them was the reverse polarity diode. Program the PROM, set the TCXO and low speed data, tune the RX filter and never see the unit again.