Radio Question

Radio Question



Looking at various Motorola radio set-ups, especially the rear handsets. Do you have a rear handset in your car, if you do, could you post a picture and explain how it works, i.e. can you select the channel you want from the handset independently from the radio upfront?

The first picture is a handset in a 1970 Pontiac. I do not know if there was a radio upfront. The second picture is a handset currently on e-bay.
 

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John ED Renstrom

PCS Member - Elected Director 2017-2020
Super Site Supporter
The mother may I set up. The one i have would be wired to the radio so it would need to be switched from the raido. But most of the motolola sutecase only had one chanel in them out here ours used state radio system
 

Peter Grave

PCS Member
Super Site Supporter
From the days of our beloved rigs radios have changed completely. They were analog today almost all two way radios just like cell phones are digital. They are not compatable so radios like you are showing will NEVER work as there is nothing they can hear and nothing they can speak to. They are now ornaments. DISPLAY. If you are looking for babble to impress viewers a modern digital scanner may work unless transmissions in your area are encripted then you just can't hear them.
 
From the days of our beloved rigs radios have changed completely. They were analog today almost all two way radios just like cell phones are digital. They are not compatable so radios like you are showing will NEVER work as there is nothing they can hear and nothing they can speak to. They are now ornaments. DISPLAY. If you are looking for babble to impress viewers a modern digital scanner may work unless transmissions in your area are encripted then you just can't hear them.
I understand that. We are on Trunk mobile radios here and have interoperability not only with most Police and fire, but also with the other two Maritime provinces.

I was just wondering how these rear handset worked back in the 70s
 

Peter Grave

PCS Member
Super Site Supporter
Back in the 70s the rear handset was not common usually they were duplexed in with the front unit. If the squad was extremely well funded or the governrnent was doing well some rigs had separate radio that was linked to a local Hospital for direct communication and advise. Remember in this era upscale mobile radios cost the price of a new Ford. As a footnote two weeks ago I was in Philadelphia picking up a burned Explorer I bought and viewing the twenty plus more the rioters burned for them. One that had not arrived yet was a brand new 2020 Dodge Durango with less than 1000 miles that the latest rioters burned just recently. The man in charges comment was "Yeah $30000.00 for the truck and $20000.00 for the Police equipment gone to a match." So as you can see radios have gone up just a bit.
 
Truthfully the answer to your question is They usually didn't work when it came to changing channel from the remote.
Not sure if that head is supposedly controlling a Motrac or later model, but they all tended to malfunction pretty much the same way and were common to secondary heads on pumpers with the secondary on the pump panel.

I should probably point out those radios are no longer legally operable due to narrow band regulations from the Federal Cookie Company.

Motorola drawer to head cables contain up to 46 wires and terminate on one end with a plug that operates in the range from works sometimes to *$@)#% never works. Chanel switching is a function of switcching which set of crystals in the drawer is functioning, much akin to which tone is coming from the siren speaker depending on where the selector switch is positioned. In any configuration of 1 drawer 2 heads, one head must be primary and how that was accomplished depends on which genius in Shlumberg specked the job. Keep in mind that drawer is only a 1 channel radio with up to 4 sets of crystals. Also keep in mind the spread of the frequencies needs to be narrow for optimum radio performance.

Usually the head on the dashboard contained a switch that disabled freq selection on that head and enabled freq selection to the rear head, when it worked. All other functions of the radio just duplicate at both heads with ambulance rears equipped with Lpad speaker volume. Radio On/Off may not be available at the rear depending on 2 wires plugged into the head, #19 & 20 as I recall. Naturally several meetings and long distance calls were required to nomenclature the switch on the dash head.

On the other end of the cable the plug to the drawer was an issue. Initial configuration was a plug for the dash (primary)
head male on 1 side/female on the back for the secondary head to plug into. Oddly, even with gold plated contact pins these were problematic. Second generation, after somebody in Shlumberg actually listened to MRO techs used one oversized plug with 2 cables coming from it.

As the paramedic concept evolved in this area a VHF system came into play lovingly called 340 for direct communication from para to hospital. Base stations were installed in hospital EDs, including one sitting in a valley that had problems transmitting to the hospital driveway, about normal to government programs. 4 times a day, every day, clerks and or nurses hospitals transmitted the house's Color Code, surgical & Medical on 340 to give incoming ambulances a hint of waiting time at ED. This allowed a loaded car heading to hospital to call his dispatch to ask availability. It also allowed dispatchers to screw with hospitals by requesting REPEAT from a hospital.

Motorola loved 340, additional radio sales. MRO shops despised it. Junior lost lunch when he discovered National running on 49mhz needed to buy additional radios for each car. Fortunately the county had been fleeced into a new GE system by a white shoed salesman, so single channel Motracs were available at low cost.

By the 80s Motorola had a lot of competition and small low priced radios from Icom, Fugitsu, King & Bendix came along to ride in the back of ambulances. Oddly the radio business always has newer and gooder, to continue the income stream, and we're now building 800mhz interoperable systems that cost millions of Dollars. Guess what is already being retrofitted and upgraded here to compensate for the computer at FCC not knowing iron rich Sewer Ontario's South shore kills propagation. Hey, what's a couple more towers and votive selectors? Evidently the Motorola people who learned that when they tried rolling out 800mhz to power companies in the 80s retired.
 

Peter Grave

PCS Member
Super Site Supporter
Anybody interested in mobile radio gear I have a 40 foot Mayflower Moving Van about 3/4 full of two way radio equipment from the 60s to the 80s six foot racks of equipment mobile and base units the oldest has been there 30 years newest at least 15 years Most stuff free if you want to come and poke through it. NO I WILL NOT LOOK FOR STUFF TO SELL AND SHIP. Next spring if scrap is up at all it goes.
 
Can I show you something in a nice UHF repeater? How about paging encoders? Need a complete radio for your Harley minus rusted out microphone holder? Perhaps a nice Motorola brick with leather covered vehicle charger/holster? Motorola lunchbox housing minus 13 D cell batterys?

Maybe I gotta visit the Motrac page on Facebook. Somebody there might be interested.
 
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