Re: [Discuss-gnuradio] Spectrum from 1 to 10 Mhz

[Gary Chatters]

On Tue, 31 Aug 2004, Jung Ko wrote:

> Hi everyone,
>
> Just out of curiosity, does anyone know what kind of modulation
> scheme(s) is used for the frequency range from 1 to 10 Mhz for over
> the air transmissions? Basically, I would like to know what can I
> expect to receive if I tune the tuner into this frequency range and
> write an application to demodulate the signal.
>


The most common is probably AM voice used by broadcast stations.
Standard broadcast extends up to about 1.6MHz.  What you hear will depend
on where you are and time of day.  Shortwave broadcast using AM will occur
at various frequency bands higher in this range.

Some shortwave broadcast stations use a digital transmission format called
Digital Radio Mondiale http://www.drm.org.  I am not a shortwave listener,
so have no idea how common it is.


You will hear a variety of stations using upper side band voice.  These
can be marine, aviation, or military.

There are several bands in that range allocated to the amateur radio
service.  In the western hemisphere these would be 1.8-2.0, 3.5-4.0,
7.0-7.3 and 10.10-10.15 MHz.  In these bands you will find lower sideband
voice, Morse code sent by on-off keying, RTTY (radio Teletype) sent by
FSK, AM voice, a phase shift keying mode called PSK31, analog slow-scan
television (SSTV) and various other minor modes.

You'll also hear a variety of other modes, digital and analog.


gc