[TrunkCom] Re: [ConnScan] Milford Police Broadcasts

Wed, 27 Aug 2003 13:11:24 EDT

I have not heard of any FCC rule or law that states as such. If any at all,=20
it would be a FCC rule. You cannot legally use encryption on HAM freq's,=20
business/industrial freq's (the DOT freq's), MURS, GMRS, FRS, Citizen's band=
s radio=20
and a couple of others. Private license holders not operating in such bands=20
can use encryption as long as their license has the FX2 (I think) on their=20
license, which covers DIGITAL use which doesn't necessarily mean encryption.

99.9% of local agencies that have normal analog radios with encryption do no=
t=20
have their main channel in the coded mode. The reason, simple: Clarity. If=20
you have ever been next to a radio that is receiving a decoded transmission,=
 you=20
will know why... You mostly hear static with a voice in the background (thin=
k=20
of being on the very fringe of a repeater and trying to make out what the=20
person is saying). Unless you have a perfectly designed system with a VERY h=
igh=20
tolerance, there is a lot of noise that can make an encrypted transmission=20
almost unreadable. Simplex is much better, but range is cut short since you=20=
are=20
not going thru a repeater.

Another reason is range. This is due what's called rayleigh fading, and=20
mostly effect's the standard DVP, DES algorithms. Because of this, the -XL (=
DVP-XL=20
etc) was developed by Motorola to overcome rayleigh fading but still didn't=20
reach as far as a clear transmission, but pretty close. Coded transmissions=20=
are=20
typically transmitted at 12kps.

Now in a DIGITAL system, you don't suffer from any of that. Because you are=20
already transmitting which is basically data, the radio and not the encrypti=
on=20
module, has already done the work in the VOCODER and all the module has to d=
o=20
is apply the encryption. In an analog radio, the module does all the=20
work...converting the audio to a digital format, encrypting it, sending it,=20=
decrypting=20
the rx transmission, converting it back to analog and out the speaker. It=
=E2=80=99s a=20
lot of work for 1970's technology.

As a side note, most radios would automatically erase their keys when the=20
power or battery was removed as a safety feature. When dealing with large PD=
's=20
etc, its a pain in the a*s to go and find the keyloader to load the key in a=
ll=20
the time, and that was if the KVL was available to the rank and file that wa=
s=20
working that shift. There were battery backup options that could be bought t=
o=20
prevent this, but on most portables, if the radio was on and you took the=20
battery out instead of turning it off first, the key was erased. The newer r=
adios=20
have an option in the programming radios that allow for infinate key retenti=
on=20
which makes life easier, but sucks if the radio is lost or stolen.

So moving on... for the most part there have been very few lawsuits or=20
challenges to running full time encryption. If any of you were paying attent=
ion a=20
few years ago, some of the news agencies were starting to make some noise wh=
en=20
the CSP announced they were going digital. Back in the day (and still even n=
ow)=20
people thing that digital IS encryption, which it is not.

In order to avoid problems, the CSP allowed the news media to run a line fro=
m=20
the CSP CEB's so that they can get the audio, as long as the media paid for=20
the extra equipment, and would not divulge any specific information, which=20
actually complies with the 1996? Telecommunications act. Essentially, the me=
dia=20
can hear a shots fired call come across the CSP radio, but cannot directly u=
se=20
the info...the media would have to send a crew out and find out for themselv=
es=20
or talk to the CSP directly.

The three letter agencies that operate are almost 99% encrypted. Plug in any=
=20
of the known FBI, Customs, etc freq's and all you will hear is coded=20
transmissions. Even the repeater identifier seems to be coded on a couple of=
 freq's=20
that I have plugged in. Earlier today was the first time in 3 months that I=20=
have=20
heard a clear transmission on a customs freq, and they were just testing a=20
radio...nothing big.

So, basically there is no known law or FCC rule that I am aware of, but in=20
terms of be practical, its normally not done, and most PD's don't want the=20
lawsuit battles or bad press to go along with it.

"Paul S." <[email protected]> wrote:
I was just reading the previous posting that Milford PD is digital=20
and it is encrypted FULL time.   I could be wrong, but  I thought I=20
read somewhere or heard somewhere that police agencies that have=20
encryption capabilities, are only supposed to encrypt their=20
broadcasts a certain percentage of the time  for example   10% of=20
all broadcasts. Has anyone else heard that fact ??  I could check=20
with the American Radio Relay League in Newington to see if that is=20
true or not. Frank Terranella is a well known lawyer that deals with=20
legal aspects of the communications arena. So if anyone knows  how=20
to get in touch with him, I'm sure he would know.

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Members, don't forget to utilize the Archive Search function on the=20
Yahoogroups/ConnScan website.  http://groups.yahoo.com/  (sign in)
This function is available to all members and is a great resource!

ConnScan - The Connecticut USA Area Scanner Monitoring Community.  This list=
=20
belongs to the ConnScan community members.  Its sole purpose is to provide f=
or=20
a forum where interested people can exchange information on the hobby.  All=20
opinions expressed herein are those of the individual contributors and do no=
t=20
necessarily reflect the views of the list owner, moderators, or of Yahoo.=20

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/=20

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