Local police method of defeating scanners ?
 

Hey all.

A small town local to me does something that I think is meant to
discourage eavesdropping on their public communications.

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

This, of course, makes monitoring a pain because the scanner stops
every time it hits the active frequency.

Has anyone else here heard of anything like this? If so, is there any
feasible way of "getting around it"?

Coceivably, I can see in my mind how defeating this nuisance could be
accomplished using some pretty sophisticated design in a scanner, but
I dont know if this has been addressed yet.

FOr now, I'm just gonna have to skip listening to Billy-Bob and Festus
down by the grain elevator.

Thanks!

PL TONE/DCS DECODE

I'd be willing to bet that the system in question uses a PL tone, and the
"key-ups" you report are not toned, otherwise it would drive the officers
and dispatchers crazy. Solution: get a scanner that has CTCSS, determine
the proper tone for this system, and enable it.

Mark

"Tempest" wrote in message
...
Hey all.

A small town local to me does something that I think is meant to
discourage eavesdropping on their public communications.

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

This, of course, makes monitoring a pain because the scanner stops
every time it hits the active frequency.

Has anyone else here heard of anything like this? If so, is there any
feasible way of "getting around it"?

Coceivably, I can see in my mind how defeating this nuisance could be
accomplished using some pretty sophisticated design in a scanner, but
I dont know if this has been addressed yet.

FOr now, I'm just gonna have to skip listening to Billy-Bob and Festus
down by the grain elevator.

Thanks!

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

Sounds like what the FCC calls, "Intentional Interference" and is unlawful.
Check with your FCC field office.

Mrjefferson99 wrote:

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

Sounds like what the FCC calls, "Intentional Interference" and is unlawful.
Check with your FCC field office.

I'm just wondering if that would be considered 'intentional interference' by
the FCC if the same folks who hold the license are the ones doing the keying up.

dxAce
Michigan

This appears to be an LTR system, and the key-ups are used to keep the
subscriber units connected with the system. Try using an LTR capable
scanner such as a BC780, and give it a go.


In article ,
Tempest wrote:

Hey all.

A small town local to me does something that I think is meant to
discourage eavesdropping on their public communications.

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

This, of course, makes monitoring a pain because the scanner stops
every time it hits the active frequency.

I'm wondering about yet another possible scenario or two. Are you sure it
isn't a "birdie" which would make it "appear" as though being keyed up? One
than perhaps the actual transmissions are strong enough to override?
Something which produces a pulsing effect which interferes on that frequency
would produce the symptoms. Another scanner nearby could produce it. Every
time it hits a certain frequency as scanning or stops there, this scanner
could be subject to it. I have 4 scanners here and there are similar
situations.

Could be the LTR - not saying it isn't, just giving another theory to look
into. Also, yes, there are some "faulty" transmitters out there, maybe one
not really aware of by the licensees! Then you have clowns with radios that
do play, though the latter doesn't sound in any way to be the problem at
hand. The radio system could have a faulty keying circuit too, especially if
using a phone line relay system. Weird things happen.

"Rich Carlson, N9JIG" wrote in message
...
This appears to be an LTR system, and the key-ups are used to keep the
subscriber units connected with the system. Try using an LTR capable
scanner such as a BC780, and give it a go.


In article ,
Tempest wrote:

Hey all.

A small town local to me does something that I think is meant to
discourage eavesdropping on their public communications.

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

This, of course, makes monitoring a pain because the scanner stops
every time it hits the active frequency.

Here in the Uk the police on one motorola trunk system used a talkgroup that
would broadcast a "Scanner trap one" "Scanner trap two" Etc. message which
would make monitoring with a conventional scanner an even worse headache
than just trying to monitor a trunked system because your scanner would...
well get caught up in the scanner trap messages. Solution? Get a trunking
scanner and lockout that talkgroup.
Melv
"Tempest" wrote in message
...
Hey all.

A small town local to me does something that I think is meant to
discourage eavesdropping on their public communications.

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

This, of course, makes monitoring a pain because the scanner stops
every time it hits the active frequency.

Has anyone else here heard of anything like this? If so, is there any
feasible way of "getting around it"?

Coceivably, I can see in my mind how defeating this nuisance could be
accomplished using some pretty sophisticated design in a scanner, but
I dont know if this has been addressed yet.

FOr now, I'm just gonna have to skip listening to Billy-Bob and Festus
down by the grain elevator.

Thanks!

"Tempest" wrote in message
...
Hey all.

A small town local to me does something that I think is meant to
discourage eavesdropping on their public communications.

When their system is not in use for broadcast, the system 'keys-up'
about every 2 seconds, as if someone was sitting somewhere pushing the
PTT button on their radio.

This, of course, makes monitoring a pain because the scanner stops
every time it hits the active frequency.

Has anyone else here heard of anything like this? If so, is there any
feasible way of "getting around it"?


This sounds like an LTR MultiNet system. If that's the case, you can't
track it with any scanner currently available, and I don't see any way
around it.

Ken