New DSC user
Chris Black <n1cp@...>
Have been a HAM and MW DXer for long time and am now starting to enjoy some of the utilities and am just getting started with DSC. I am using an Icom 7300 RTTY mode with Wellbrook 1530LN antenna and have had no trouble with Navtex and DSC with SeaTTY but having trouble getting DSCDecoder to work. Wondering if possibly someone West Coast US using this program. Also any suggestions concerning another program welcome.
Chris near Seattle WA
On Thu, 14 Feb 2019 at 01:05, Chris Black <n1cp@...> wrote:
Hello Chris and welcome to the group.
I'm the other side of The Pond to you but I do use DSC decoder and
SeaTTY. Both of them work perfectly, and I'd suggest SeaTTY has the
edge over DSC decoder on MF and HF DSC.
Let's assume you want to monitor 8414.5 Kc/s
My receiver is set to USB mode and 8413.25 Kc/s, giving an offset of
1250 c/s (we old-timers don't do Hertz!).
On DSC decoder, in the VIEW > SPECTRUM window you need to make sure
that the red horizontal line is centred on 1250 c/s. If it isn't,
you'll need to click on the red line, see what the reading on the
right-hand side of the window says, and use the cursor to adjust the
line so that it DOES show 1250 c/s. You can of course choose any
offset you like within reason. 1700 c/s is what the maritime world
uses so in that case your receiver would need to be in USB mode and
tuned to a frequency 1700 c/s below the assigned freq (e.g 2185.8 for
2187.5 Kc/s) and the red line on DSC decoder would need to be centred
on 1700 c/s
I tend not to use the auto-tune facility. As for the demodulator,
under OPTIONS > demodulator I've selected 'Alternate HF modem' but
left the other options unticked.
I'm taking a guess here and saying that you need to set the decoder to
work with inverted tones.
Click the MF/HF and select 'inverted tones'
In that window you should also see the value of your offset displayed
I can remember talking someone through the setting-up procedure for
DSC decoder (even though it's adequately described in the HELP file).
He was getting nothing on the screen but was convinced the decoder was
set up correctly. It was, but he'd accidentally hit the vertical
scroll bar and was looking halfway down the screen where there was no
text. All the text was at the tiop. He ran the scroll bar back to the
top and there were the messages.
Anyway, give it a go and see what happens. If it doesn't, sing out and
we'll see if we can see if Plan B works. I may have forgotten
Ah, one last point. Don't overcook the audio in. Keep it low enough so
that the signal doesn't show any distortion. Again, this is mentioned
in the HELP file
Chris Black <n1cp@...>
Thanks Richard for that helpful info. Assuming I get all the setup aspects working I still have some questions. I believe in DSCDecoder you are supposed to see the shore station name which comes from a text file. I saw nothing in the documentation just came across this file accidentally. At any rate it appears to be rather out of date. There is also supposed to a Ship Info log. Not sure what’s in there or where it comes from.toggle quoted messageShow quoted text
With SeaTTY I have decoded messages but only see the ID numbers. Is there an up-to-date source of information for these? As example, I see shore station numbers from SeaTTY logs that are not in the DSCDecoder text file. In DSCDecoder my signal traces appear to match the examples given but the other screen looks nothing like the example.
Anyway, will press on. Thanks again
Best de Chris
On Feb 14, 2019, at 12:12 AM, Richard Ware <richardjware@...> wrote:On Thu, 14 Feb 2019 at 01:05, Chris Black <n1cp@...> wrote:Hello Chris and welcome to the group.
On Thu, 14 Feb 2019 at 13:56, Chris Black <n1cp@...> wrote:
The coast station file can be edited by the user using notepad or a
similar editing tool. DSC decoder must be closed down for any
amendments to take effect. You can delete stations you're never going
to hear or add new ones.
Remember though that if you do add additional stations, spaces between
the data columns must be padded out using the spacebar on your
keyboard and not the TAB control.
Just the follow the formatting.
The shipinfo log: I think Bev, the DSC decoder programmer, assumes
that anyone using DSC decoder will also be using his Shipplotter
program. With Shipplotter, every so often, and when you close the
program down, a file is created called "ship-id.txt". This, rather
unsurprisingly, contains a list of ships that are on the Shipplotter
server at the time.
Now, what happens is this.
Assuming you ARE running both Shipplotter and DSC decoder, you need to
point your DSC decoder to the ship-info.txt file in Shipplotter. Yes,
I know it sounds a bit fiddly and confusing but what now happens is
this. If DSC decoder finds a valid entry in the ship-info file it will
add that entry to the ship-id file in DSC Decoder.
If you're NOT running Shipplotter then I assume you have to manually
add ship stations and point DSC decoder to THAT directory. instead
Yes, it's fiddly. I don't use the facility anyway as I prefer to just
see the ship's MMSI number.
I hope I've got those files the right way round as I'm away from home
right now and working from memory. Dangerous !
SeaTTY does not add station names to either ship or coast station MMSI
numbers as names do not form part of a DSC message
You'll also notice that SeaTTY MMSIs are 10 digits (the last one is
usually a zero) rather than the 9 you see in DSC decoder
I admit that the HELP file for DSC decoder isn't exactly overloaded
with info. It could do to be re-written. Some of the the stuff I've
mentioned above was gleaned from messages on the shipplotter group.
I've made loads of notes in a little black book !
Chris Black <n1cp@...>
Thanks for that. Don’t know if you use NAVtEX but is there some kind of message database where you can verify messages. I see conflicting info on the location identifier.toggle quoted messageShow quoted text
Back to DSC, is there a reference for the shore location numbers. You mentioned editing but that presumes you know what to edit.
On Feb 14, 2019, at 6:31 AM, Richard Ware <richardjware@...> wrote:On Thu, 14 Feb 2019 at 13:56, Chris Black <n1cp@...> wrote:--------------------------------------------
On Thu, 14 Feb 2019 at 15:29, Chris Black <n1cp@...> wrote:
I don't 'do' Navtex
As for the shore station MMSI numbers, this is the one we use
It's formatted for YADD, not DSC decoder, so you'll have to look on
that list for the station(s) you want, make any notes and add the info
to your coaststaion.txt file
I know there's a list of SHIP MMSI/name tie-ups in a format you can
use for DSC decoder but offhand I can't find one for coast stations.
I'll have another search
(John, is there such a list for DSC decoder?)
Here's the link to the list of SHIP MMSI numbers for DSC decoder anyway
You need to select the shipid.txt format
Remember to rename your original file as a precaution in case things
go wrong, as the new one will become your new shipid.txt file and
that's the one you'll be using
Chris Black <n1cp@...>
Hi David, I really appreciate your inputs. I think I have come to the conclusion that DSC is more of a full time job than I need at this time.toggle quoted messageShow quoted text
In addition to Ham radio, I DX MW and NDB and dabble some in Navtex and sometimes even try to have a life, hi!
All the best, live long and prosper
On Feb 14, 2019, at 7:51 AM, Richard Ware <richardjware@...> wrote:On Thu, 14 Feb 2019 at 15:29, Chris Black <n1cp@...> wrote:--------------------------------------