Help with radio dispatcher protocol?

[RadioBob1000]

Hi,

My hobby is researching the JFK assassination.

Part of the evidence in that case is a radio recording of Channel 1. Someone, (we do not know who) had an open microphone on Channel 1 during the assassination. The open microphone caused heterodynes to be created when an officer would try to access the open channel.

However, it appears to me that when the Dispatcher accessed the open Channel there were no heterodynes.

Here is my question...

When the Dispatcher is broadcasting does he "own" the Channel ? Can anyone in the field interrupt the disptachers transmission?

When I say "in the field" I mean the many motorcycle policemen and police in cars that were working that day.

We are talking 1960's protocol and technology.

Thanks in advance. I hope this is the right place.

 

[KB7MIB]

Assuming a repeater was in use, the link from the dispatch center to the repeater is typically by a dedicated phone line, or nowadays, a fiber optic or microwave radio link, rather than via the repeater input as radios in the field would use.
So, yes, a dispatcher can "take over" the repeater when a unit, or a malicious third person, has an open mic in the field.

Nowadays, it can work both ways. If a dispatcher is talking, and a unit in the field needs to break in with emergency traffic, the dispatcher will still hear that unit, even if the dispatcher is talking. The dispatcher can then pause, and the unit in the field can go with their emergency traffic.

John
Peoria

 

[Golay]

Even if comms back then were plain old analog simplex, it kinda makes sense that the base would have enough power or overcome an open mike. Mobiles and portables may not.

Curious, do you know what the radio recording is listening to? Is it what the base is hearing, what another unit is hearing?