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TELE-audiovision International — The World‘s Leading Digital TV Industry Publication

— 01-02/2015

dozen shortwave bands to

choose from. If you are inter-

ested in listening to interna-

tional shortwave broadcasts

begin with the 31m band

covering frequencies 9.400 –

9.900 MHz. The 31m band is

one of the more heavily occu-

pied bands where you’ll find

plenty of interesting listening

24/7 due to favorable iono-

spheric conditions affecting

this slice of spectrum. Sadly,

many old-time shortwave

broadcasters such as Swiss

Radio International, Radio

Austria, and Radio Moscow

have “gone dark” (ceased

broadcasting) on shortwave

due the advent of satellite

and Internet radio, but plenty

of entertainment from around

the world still exists on short-

wave, so tune in and listen.

In addition to international

broadcasters, the HF spec-

trum is occupied by military,



cal, amateur radio, marine,

weather, and other utility

(“ute”) communications using

voice (Upper or Lower Side

Band) and non-voice digital

modes such as CW, RTTY,


HFDL, JT65, PSK31, and

SELCAL to name a few. In-

teresting transmissions such

as synoptic marine weather

reports to mariners, QSOs

(conversations) between ham

operators using Morse code,

PSK31, and teletype, fac-

simile weather maps of dif-

ferent regions of the world,

infrared satellite images, and



sages from ships at sea are

being transmitted around the

clock. The good news is that

the SDR dongle is sensitive,

selective, and stable enough

to allow decoding of many of

these non-voice digital trans-

missions. This aspect of the

radio listening hobby is re-

ferred to as HF Utility (“UTE”)

monitoring. If you are inter-

ested in these types of trans-

missions an excellent source

of information is The Spec-

trum Monitor Magazine (www. ),

a monthly on-line magazine

staffed by columnists with a

wealth of experience in the

radio listening hobby.

Use of digital mode decod-

ing software will significantly

enhance the overall experi-

ence with your SDR dongle as

there are many exiting and in-

formative transmissions being

sent by commercial, military,

and amateur radio entities.

Two excellent programs wor-

thy of consideration are fldigi


) and MultiP-



which feature decoding of

many common digital modes

including RTTY, FAX, CW, PSK

31, NAVTEX, Sitor B, etc. Two

other digital modes used by

commercial interests include

SELCAL (Selective Calling)

and ALE (Automatic Link Es-

tablishment). One word of

advice though: before ventur-

ing into digital mode decoding

software become thoroughly

comfortable with using your

SDR dongle. Take your time

and remember that the learn-

ing curve will be very steep

the first few weeks. If you be-

long to a radio club perhaps a

member already has experi-

ence with an SDR dongle so

tap into their knowledge and

experience. If you are on the

fast track then I suggest you

check out YouTube as it con-

tains a prodigious number of

user videos by those already

experienced in the hobby. Fi-

nally, remember that at a cost

of $16.00 USD a dongle SDR

will not perform on par with

commercially available SDRs

costing several hundred dol-

lars. However, for its minimal

cost you’ll get a lot of “bang

for your buck” as we Ameri-

cans say.

13. RTTY (RadioTeleType) transmission from German station DDK 9 broadcasts marine weather

for locations such as Western Europe. You’ll need a good decoding program such as MultiPSK to

decipher RTTY transmissions. SDR# is running in the foreground with MultiPSK in the background.

The audio stream from SDR# is fed directly to MultiPSK.

14. Facsimile broadcast from US Coast Guard Station NMG, New Orleans, LA, with map of coastal US

and Caribbean. Many stations service the marine community with facsimiles containing important

meteorological information in the form of weather maps and satellite images. SDR# is running in the

foreground with fldigi (decoding software) in the background.