8,414.5 KHZ DSC frequency ???

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Saint

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8,414.5 KHZ USB can someone tell me if this is a Digital Selective Calling (DSC) frequency or a Navtex frequency. I thought it was DSC but I am picking up all Navtex messages on this frequencies.

Also UTC 1:41 - 6,312.000 - KHZ - DSC I am picking up Navtex Messages also
Steve
 
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W4KRR

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I thought NAVTEX was 518 khz?

I've been trying to decode GMDSS using MultiPsk (as well as Sorcerer and a couple of others) and I am getting nothing.

I have the receiver tuned to 8414.5 USB, and the MultiPsk software mode set to "GMDSS" and I get a signal in the waterfall, and I can hear the tone, but no text.

I tried YADD (Yet Another DSC Decoder), and got nothing. Then I tried YAND (Yet Another Navtex Decoder), and I finally got decoded text.

So if 8414.5 is NAVTEX, what is the difference between it and GMDSS? I thought I had this figured out.
 

Saint

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Navtex

I thought NAVTEX was 518 khz?

I've been trying to decode GMDSS using MultiPsk (as well as Sorcerer and a couple of others) and I am getting nothing.

I have the receiver tuned to 8414.5 USB, and the MultiPsk software mode set to "GMDSS" and I get a signal in the waterfall, and I can hear the tone, but no text.

I tried YADD (Yet Another DSC Decoder), and got nothing. Then I tried YAND (Yet Another Navtex Decoder), and I finally got decoded text.

So if 8414.5 is NAVTEX, what is the difference between it and GMDSS? I thought I had this figured out.

I use Yand to decode Navtex on 8.414.5 and 6.312.0 kHz
I have yet to decode any DSC
Steve
 

W4KRR

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I use Yand to decode Navtex on 8.414.5 and 6.312.0 kHz
I have yet to decode any DSC
Steve

I used Yand for the first time today to decode NAVTEX. I thought 8414.5 was GMDSS, which probably explains why it didn't work when I tried using Yadd.

But, Yand shows 518 and 490 khz, and Yadd shows 8414.5, yet Yadd won't decode 8414.5, whereas Yand will.
 

Saint

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yand

I used Yand for the first time today to decode NAVTEX. I thought 8414.5 was GMDSS, which probably explains why it didn't work when I tried using Yadd.

But, Yand shows 518 and 490 khz, and Yadd shows 8414.5, yet Yadd won't decode 8414.5, whereas Yand will.
Yea' I noticed the same discrepencies also with these decoders.
Steve
 

ka3jjz

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I won't try to explain software differences in decoding - too much variation in receivers, bad decodes, whatever - but I think part of the issue is that folks are confusing the purposes between GMDSS and NAVTEX

GMDSS is a selcall system- a DSC broadcast that is nothing more than a signaling mode...see this reference from our digital decoding FAQ

https://www.sigidwiki.com/wiki/GMDSS_Digital_Selective_Calling

Now NAVTEX - which is built off of the Sitor-B protocols - is for news and maritime broadcast information. It's sometimes also referred to as Radio-Telex, and you can find more information here...

https://www.sigidwiki.com/wiki/SITOR-B

also see Bill Hepburn's excellent website on the subject, which is linked in the article above

Both modes have a very unique and distinct sound; you simply can't mistake one for the other. You don't even need a waterfall to tell the difference. There are audio samples of both modes on the UDXF digital page..

Digital Modes

Mike
 
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