Help me ID please

Status
Not open for further replies.

woebbers

Member
Joined
Apr 15, 2010
Messages
257
Location
Lewes Delaware
to all you utility listners.

Im trying to send a spectrum of a signal I recieve in quite a few places on the bands. Does this pic help identify it? sounds like a motorboat


Sal
 

Attachments

  • DDCspectrum.jpg
    DDCspectrum.jpg
    31.5 KB · Views: 485

Token

Member
Joined
Jun 18, 2010
Messages
2,380
Location
Mojave Desert, California, USA
Unfortunately just a spectrum shot like that will not be enough for a positive ID. There are several things that can make that shape on a spectrum display. The addition of a waterfall would help greatly as it shows the trend over time.

Also, time and date (in UTC) would help.

Yes, what you have there is quite possibly WEFAX, probably NMC out of Pt. Reyes California. These kinds of stations send their images on a specific schedule, and the time could be used to confirm that NMC was indeed active at the time you saw/heard this signal.

However, this frequency has also had STANAG 4285 traffic before, and your spectrum image could also be that. A waterfall of the DDC window would clear it up between the two possibilities I have mentioned.

As for software to decode the images, there are several out there. WinRadio themselves make a "Digital Suite" that will interface seamlessly with your Excalibur. It works, is very stable, and has a fairly easy to use GUI. However, for the price it is pretty limited as to what modes it does. A free software is MultiPSK, it is very capable decoding many modes and working well, but the interface is not the most intuitive in the World. A Google search for "HF FAX Software" will show a lot more options, there are probably hundreds of possible programs out there, some pretty good, others pretty junky.

T!
 

woebbers

Member
Joined
Apr 15, 2010
Messages
257
Location
Lewes Delaware
Token

I have that suite of software but have had little luck decoding anything...im mainly looking for wefax and some news. Im just not sure of the modules to choose or the modes to put them in.

Thanks Again
Sal
 

ka3jjz

Wiki Admin Emeritus
Joined
Jul 22, 2002
Messages
25,387
Location
Bowie, Md.
News broadcasts have been gone from HF for a LONG time now. Every once in a while one pops up, but it's rare. I don't know if the WLO broadcasts are ongoing - worth a check (see this thread). I really wish distributors would stop advertising this cxxx...

As for weather FAX it's all over the place. You can get the semi-official listing of stations from the NWS listing (note that this is a PDF file) or just watch the various utility newsgroups - they are often reported.

best regards...Mike
 

Token

Member
Joined
Jun 18, 2010
Messages
2,380
Location
Mojave Desert, California, USA
Yes I the advanced digital suite by winradio

OK, after you learn to identify the sound of a WEFAX by ear/eye or after you find a freq list of WEFAX signals ( such as http://www.nws.noaa.gov/om/marine/rfax.pdf ) you will be ready to decode them. Receive them in USB mode for the most part.

Under "Plugins" in the top menu bar of the Excalibur select "Signal Processing" and then "Advanced Fax Decoder".

The Demodulator mode will have to match the mode of the station, this is not the USB/LSB receiver mode thing but rather the mode of the FAX, most of the time FM. Yes, FM or AM here even if the receiver is USB or LSB.

The Rows/minute will quite often be 120.00, but some FAX transmissions may use another value, the shced I posted above will tell you.

Most of the other default values should work.

When you tune to a FAX in progress jsut hit the "Receiving" tab under the "Received Image" tab, and the image should start building up. You may have to adjust frequency to get a good white/black ratio.

T!

(edit) if you come into the #wunclub IRC chat and I am in there feel free to ask questions, if I am there I can answer them in real time and maybe get you on a FAX TX or two.
 
Status
Not open for further replies.
Top