Date: Fri, 11 Sep 92 02:34 GMT
From: Jeff Garber <0005075968@mcimail.com>
Newsgroups: comp.dcom.telecom
Subject: Cellular Frequencies
Organization: TELECOM Digest
X-Submissions-To: telecom@eecs.nwu.edu
X-Administrivia-To: telecom-request@eecs.nwu.edu
X-Telecom-Digest: Volume 12, Issue 700, Message 9 of 11

I ask the following questions with no radio knowledge whatsoever.  I
understand that cellular frequencies are in the 869-894 MHz range.  I
also understand that scanners now block this range, but one can hear
cellular conversations over the 895-920 MHz range with the cellular
user sounding more faint than than the land user (it seems to me that
one should be able to hear the RADIO user better with a radio
scanner).

I'm wondering if it is illegal to listen in on these frequencies. In
other words, does the law say it is illegal to listen in on cellular
calls, or does it specifically mention 869-894 MHz.  Why isn't 895-920
MHz blocked on scanners since you can overhear cellular?  Also, why
would the party on the other end of a cellular call sound stronger
than the cellular user?


Jeff Garber <MrFone@mcimail.com>    My opinions are just that. 


[Moderator's Note: Actually, cellular is at 824-851 megs and 869-895
megs more or less. The one group is base to cellphone; the other is
cellphone to base. In both instances, it is over the airwaves, but the
transmission from the base, or tower is going to usually be stronger
than the other way around. The cellphone transmits to the tower/base/
landline and the tower/base/landline sends this back to the cellphone
along with whatever the (landline) caller is saying. The towers are of
course fixed in one location while the cellphones are moving around.
If you happen to overhear a frequency used by a tower that is close to
you it will always be active, loud and clear. Other frequencies may be
for a tower several miles away ... it won't come in as well. In the
group which is cellphone to base, you will only hear those that are
close to you to start with -- usually loud and clear. Once their
signal starts to get weak, they'll shift to another tower and the
scanner will start cycling again. One 'problem' (smirk!) reported by
people who illegally monitor cellular conversations via their scanner
is that one never gets to hear the *entire* conversation from start to
finish. The scanner will be cycling -- searching for something -- and
lock in on a conversation in progress. As one listener put it, " ...
about the time the conversation started to get juicy -- really
interesting to listen to -- the vehicle moved out of range and the
tower dropped the call, giving it to another tower somewhere. I tried
stepping quickly around the band manually, but never could find it. "

Ahhh -- too bad! It is illegal to listen to cellular calls, period. It
is also quite easy to do the mods required on most scanners with 800
megs capability to bring those frequencies in. Some Radio Shack
dealers sell the PRO-34 scanner (my model) with a straight look on
their face then on your way out the door hand you a crudely photocopied
sheet of paper with pictures of the circuit board telling you to pull
diode D-3 and D-4 to recover the full band ... but only to be done
when the scanner is being exported outside the USA, of course ... of
course!  PAT]