[TrunkCom] partial encryption and if so how is this possible?

[Dewey]

Hi Jeff, and Happy New Year,

I've seen this on our old VHF Saber's.  When in the clear mode, the
portables will still receive and decrypt transmissions that were using the
same encryption code.  In other words, if you and I had radios that had
encryption codes to talk to each other, and you called me in secure mode,
but my radio was set to open (unsecured) mode, I would still get your call.
When I did, if I didn't pay any attention to the secure/open mode switch,
and didn't look at the display to see the encrypted symbol, I would reply in
open mode, and you would receive my signal.  To a scanner, your transmission
would be encryption noise, and my transmission would be clear.

Hope this helps, take care,
Dewey


-----Original Message-----
From: trunkcom-bounces at mailman.qth.net
[mailto:trunkcom-bounces at mailman.qth.net]On Behalf Of Jeff Kenyon
Sent: Friday, January 07, 2005 09:36
To: trunkcom at mailman.qth.net; scan-l at listserv.UARK.edu
Subject: [TrunkCom] partial encryption and if so how is this possible?

Good morning to all on the list.  I have noticed that when listening to
conversations on Michigan.s digital 800 MHz system (MPSCS) there have been
times where conversations are partially encrypted.  This morning I heard
what sounded like some kind of road commission or something, but one side
of the conversation was clear and the other was encrypted.  I.ve never
known any system to do this, and the person who was clear wasn.t asking
the person who was encrypted for a retransmit or anything.  As I said I
only got to listen to this for a few minutes and couldn.t guess on what
the agency was, but I found this to be strange.