[Premium-Rx] What can I hear in the 1.5 to 3 GHz Range??

[Dave Emery]

On Sun, May 01, 2005 at 03:08:34PM -0400, Aidehua at aol.com wrote:
>  
> There are an increasing number of receivers becoming available that  hear up 
> to 3 GHz, including the rumored Icom ICR-8900....Wondering what one  might be 
> able to monitor in that range.....Just got back from Japan and the AOR  series 
> are fine examples that cover this range as well.  Your input is  appreciated.

	Most signals in that area are complex wide band digital signals
such as PCS phones (cellphones), WiFi (wireless LANs), XM and Sirius
satellite radio, and various private and government microwave systems.
CMDA  spread spectrum in its various generations, GSM, Edge, and UMTS
and for microwave fixed point to point or point to mobile systems 64 and
256 QAM and QPSK/8PSK are all used.   Some (notably GSM and Wifi) are
frequency hopped.  Wifi and Bluetooth use hopped burst GMSK.

	Iridium and Globalstar transmissions can be found around
1610-1626 mhz - but again digital and complex formats.   Globalstar also
operates around 2.6 ghz.

	And the GPS L1 frequency is 1574.2 mhz with spread spectrum GPS
BPSK signals on it.

	There are a few simpler narrow band signals left - for another
couple of years there is INMARSAT A which is NBFM on 1535-1543 mhz but
it is being phased out.   Other INMARSAT signals are narrow band digital
in various formats using vocoded voice.

	And for another little while there is still WEFAX in nbfm format
on 1691 mhz.   It is scheduled for phase out and replacement soon by a
digital format called LRIT.    Other digital weather satellite signals
exist in that band from 1680 to 1710 , but are wide band and somewhat
complex though hardware and software to demodulate them is available.

	Other occupants of the band include wide band FM TV links for
remote pickup and newsgathering around 2-2.2 ghz (and some DVB-T DSNG
transmissions in OFDM digital format).   Most of these are 6 mhz or 18
mhz wide...

	And between 2.2 and 2.3 ghz is the major S band downlink band
used for US spacecraft to ground telemetry.   Some narrow band signals
here, many more wide band, but all basically digital PCM data in some
form or another though once in while there is analog FM TV here from
rocket cameras.

	And there is a ham band at 2390 to 2417 and a ham space
assignment at 2304 widely used with amateur satellite down links that
still include a variety of conventional narrow band signals such as SSB,
CW and nbfm.

	Marine and airport radars can found between 2700 and your limit
of 3 ghz...

	You may find some narrow band cordless phone signals in the 2450
ISM band, though they are supposed to be frequency hopped... some cheap
ones use nbfm instead of digital.   The 2450 ISM band, in addition to
WiFi links also contains FM video from cheap wireless cameras and remote
TV senders.   Lots of those around for security and things like nanny
cams.   But these are wide band signals, not narrow band.

	And there is a federal band from 1710 to 1850 mhz that contains
various narrow and wide band federal signals (slowly being emptied for
conversion to more cellphone spectrum).

	And there are several narrow ranges which are being opened up
for more or less conventional mobile including one around 1680 mhz.

	In general you will not find many nbfm or other analog
modulation signals in this range receivable on a normal narrow band
scanner type receiver, though it is certainly being more and more
actively used by modern wireless systems so there is considerable RF
there.

	And needless to say, in the USA even if you could demodulate 
many of these signals it would not be legal under the ECPA.   Ham band
signals, weather satellites and some others are legal... and of course
in other countries there may be different rules.

	Googling "frequency allocation chart" will get you a number
of links to allocation charts and discussions.

-- 
   Dave Emery N1PRE,  die at dieconsulting.com  DIE Consulting, Weston, Mass 02493