[Boatanchors] Looking for SNC Xmfr P3546 for Johnson T/R Switch

rbethman rbethman at comcast.net
Tue Oct 13 12:34:02 EDT 2015


Hello All,

I have several High Powered Broadcast Transmitters within about 3 to 5 
miles.

I never had any issues with the Johnson T-R Switch.

The biggest PIA we ever had here was the infamous BPL experiment/fiasco!

We had to finally get the FCC out here to show them what we were getting 
across the HF bands as we moved around the entire city.

Even the underground distribution system was affected.  I just obtained 
one of the Modems from the Utility company while they were tracing a bad 
feed, and had the pad mount transformer opened up.

Although it was just setting in there and no longer set up, I could see 
why it had been an issue.  All plastic enclosures, no shielding except 
inside the modem only around the processor. Everything else was 
unshielded, even all the cabling.

Regards, Bob - N0DGN


On 10/13/2015 11:37 AM, Bill Cromwell wrote:
> Hi Dennis,
>
> We can have all kinds of problems from high powered broadcast 
> transmitters nearby even without a Johnson (or simililar) electronic 
> T-R switch. I expect the same measures to correct the problems would 
> apply.
>
> 73,
>
> Bill  KU8H
>
>
>
> On 10/12/2015 09:17 PM, Dennis DuVall wrote:
>> A word on “electronic” TR switches,  If you are located anywhere near 
>> a high power BC station expect cross modulation problems.
>>
>> Dennis D.  W7QHO
>> Glendale, CA
>>
>> *******************



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