Radio proximity

[Citizen]

My question is about radio proximity.  

A modern day transceiver (HT, mobile) is both a transmitter and a receiver built into one unit.  And I understand that RX is automatically shut down whenever TX is initiated, thus saving the receiver internals from being fried.  (Pros can correct me, is this true?).

Many, many years ago (and in a place far, far away), in the Air Force, I was a radio man.  Mostly we used HF-SSB and some VHF.  The transmitter and the receiver sites where massive facilities and physically located literally miles away from each other and thus didn’t have the problem of frying receivers to worry about.  

And further, as a kid I remember my dad’s old ham setup.  The transmitter and the receiver were in separate metal chasses, as were the power supply and some other equipment he had, (filled up his entire 72" wide radio/hobby table).  I think each unit must have been shielded because they weighed about a ton each.  I don’t recall the RX being shut down when he transmitted, but I was a small boy, and did not understand the equipment…one of them could have been some sort of switch that shut down RX as needed, I dunno.
 
Today, in my “shack” (a 24 inch wide, 2-level shelf I built), I have several mobile radios physically mounted right next to each other and a couple of power supplies.  My question is, if any two or more radios are on, and I transmit on one, will it fry the internals of the those receiving, because they are physically located right next to each other?

 

Comments please, and thanks!

 

...

 

Edit:  Should have ready 72 inches, not 72 feet.

[mbrun]

The fact that your radios are side by side is not an issue. A radio-enthusiast’s shack is full of radios, often times online at the same time but connected to different antennas.

 

You are correct. A transceiver is both a transmitter and receiver, hence the name.

 

Within a transceiver, the receiver is internally disconnected from the antenna when the transmitter is in use. If this was not done, yes the internal transmitter would/could fry the internal receiver, which by design is intended to pickup low level signals.

 

If you have multiple transceivers in your radio shack, it is a certainty that when you are transmitting on one of them, this signal will have an impact on the performance of all transceivers that are currently listening. That is normal. However, the higher the quality the receiver, the better the quality of installation practice, the less of an issue this is

 

Hope this helps.

 

 

Michael

WRHS965

KE8PLM

[Citizen]

Thank you for that clarification, that explains it.  I didn't know it was the antenna that got disconnected (I thought it was the RX electronics that got temporarily shut down). 

 

Makes sense now, and I feel better that I'm not frying my side-by-side radios.  This info also alerts me to not try to share an antenna (like with a splitter) between radios.

 

Thanks again!

 

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[OldRadioGuy]

The answer is "it all depends".

Most receivers (especially HT's) have some protection.

But if you put a high enough power close enough something bad will likely happen.

 

I've used my 5W talkies a foot apart with no problem.

I would not try this with a 50W radio though.

Might be OK or might not.

 

Vince