Skanti Leisure VHF 1000P DSC radio

[Plevier]

Hello Ray

Well done on brilliant detective work. I'm afraid i haven't been back to the boat yet to try anything.

However I agree with everything you've posted until you get to the NMEA details where I just don't know. Mine is connected to an Interphase 7CVX which according to the manual outputs NMEA standard 0183 or 0180. I don't know the difference. I'll have to go through the setup routine for that too! At least I don't have the Seatalk conversion complication.

On its input the 7CVX recognises GGA and GLL, it doesn't mention ZDA in the manual.

How does one view what sentences are being sent?

I can confirm the radio always shows the time of the internal clock, whatever I do to its settings and the GPS.

The Skanti manual on p20 note 5 says "If a GPS is connected, time and position are automatically inserted." and in the distress call set up format on p23 it shows you getting the chance to input lat, long and time if GPS is not connected but skips all of them including time if GPS is connected.

My suspicion is that the GPS time connection will override the internal clock and use a UTC time for a distress call but the handset always displays whatever local time you have selected, never GPS time. I think the only way to check would be to make a DSC distress call.

It's a pity the Skanti manual is so totally devoid of specifications and installation instructions. I can't find anything downloadable on teh Thrane & Thrane Denmark website. It sounds as though your local agent only has limited info too.

 

[Gypsy]

I solved the Skanti UTC time problem on my system today - interesting because until your post I didn't know I had a problem!

The Skanti definately needs the NMEA sentence ZDA for time and date. When I monitored the NMEA data I was feeding to the Skanti it only had GLL plus other heading sentences because I was taking the data from an output of my autopilot - it was convenient and as it picked up lat/lon OK I just assumed that was the end of it.

Today I connected the full data set supplied by the ST-->NMEA converter and within seconds I had UTC time and date on the Skanti. BTW, once it sees the ZDA signal, it updates the internal clock so even if you remove the GPS it continues counting from the last known good ZDA/UTC signal.

Both GGA and GLL include time in their data but not date. ZDA has both time and date and it seems that is the only sentence the Skanti will take the UTC info from. I suspect, but have not proven, that it will take lat/lon from either GGA or GLL.

I expect you have the same situation, the Skanti is seeing GLL and/or GGA but NOT ZDA. I looked on the web for a specification for your Interphase but I couldn't find the exact model. It seems some models allow you to select what signals are sent out the NMEA output port but unfortunately ZDA is not one of those mentioned (GLL, VTG, BOD, XTE, BWC, RMA, RMB, RMC, APB,WCV, GGA, HSC, HDG). Take a close look at your manual to see if yours may allow the choice of ZDA, but somehow I doubt it. The sentences are primarily aimed at feeding autopilots. It is a pity the Skanti doesn't support RMC becuae it has all the information needed - lat/lon and time&date. Oh well.

To view the NMEA data you need a PC running a Serial Communications/Terminal programme. It needs to be only a simple one, Hyperterminal supplied with Windows XP is fine. Unfortunately MS took it out of Vista and W7 so if you don't have XP or earlier you need to find an alternative. There are a few on the web - some free and others available for 14day trial. You also need to be able to connect to the NMEA signal with a serial port, either through a 9pin 'COM' port in your PC or via a USB-Serial adaptor. Once you have the PC and serial port you connect the NMEA -ve to pin 5 of the 9pin and the +ve to pin 2. You set the Comms program to 4800baud, 8bits, 1stop, no parity. Note the ZDA sentence is not transmitted as often as many others, you may need to wait 20secs or so to see one.

If all of the last par is gibberish or not easy to do, then we have to work from the specs. In the end, if you are sure you can't get ZDA from the Interphase then you are stuck with the internal clock. However, since it is backed up by an internal lithium battery it should remain accurate enough over a season and by the time you are finished with this exercise you will be able to work with the Skanti menu blindfolded to set the clock.

Well, it has been an interesting exercise. I have learnt more about the Skanti than I knew before AND I fixed a problem I didn't know I had. I hope there is a fix in this for you too.

 

[Plevier]

Ray
I think you have won all the coconuts in the fair! What a shame so much manpower has had to go into this just because the manual is total cr*p. The user interface doesn't help either.
The manual for my 7CVX plotter does not mention any options for selecting output sentences. I can just choose format of NMEA180, 183 or 180CDX whatever that is.
If you use an external GPS with it, ZDA is not listed as an input sentence that it recognises. It lists BWC, DBT, DPT, GGA, GLL, GSA, GSV, HDG, HDM, HDT, MTW, PCMPA, RMC, VHW, VTG, VWR, VWT. So how does the plotter know the time and date - it does - if ZDA is the only sentence containing it?
The plotter apparently has a setup routine that lets you display the incoming data stream on screen, I will try it.
Incidentally a Wikipedia article says ZDA is only rarely used.
I did find one other thing to try on the Skanti. P28, function menu tree, DSC:settingsositionosview should display UTC time, DSC:settings:time date:view should display tzone, local time and date.
I'll try that probably tomorrow.
So if it isn't getting UTC from the GPS, and you have set the internal clock to local time, I wonder whether it timestamps the transmission with local or UTC? Perhaps it's important to set the zone correctly.

Just a thought - doesn't GGA include date information, surely that must be part of the "GPS fix data"?

Argh! : followed by letter p seems to come out as a smiley! Sorry!

 

[Plevier]

Ray

I have found a service manual that I'm sure would interest you. It includes this:

1.2 Change of battery for back-up
(Not for TU 1000 P)
The VHF system is constructed with a real-time clock which uses a lithium battery for power back-up. By
means of this battery, it is possible to maintain track of time and date even though the VHF system has
been turned off.
The capacitance of the battery is 220 mAh (milli Ampere hours), and if the real-time clock consumes a
current of about 12.5μA, the battery should last for a period of app. 2 years. However, in practice this
period will be longer because the battery is only used when the VHF system is turned off.
The battery is located at the AF & processor module ( 632250 ) and is soldered to the PCB to obtain
mechanical stability.

In another part of the manual it says the battery is a CR2032. Pity it's soldered.

Mine's 8 years old now so I may well find the clock is not keeping time.

I've lost where I downloaded it from but can email you a pdf if you PM me your email address.

 

[Plevier]

Installation manual at http://www.generalmare.com/PDF/SAILOR/MANUALI/002RT4800_01-in.pdf for the Sailor RT4801 that the Skanti became.
It says interface for GGA, GLL and ZDA. Doesn't explain if all required.

 

[Gypsy]

Thanks for the kudos, you are doing pretty well in the investigaing stakes too with your service manual find. I have PM'd you my email address. I already have the install manual but thanks for the link.

Does your system have an external GPS unit? If so it will be very interesting to monitor the incoming data. Unfortunately it is unlikely to provide ZDA from the look of the info so far. My guess is your chart system gets the date from RMC. It is one of the few sentences which contain time and date of fix, I have found only RMC, ZDA and TRF but there may be others. There are quite a few with time only but the radio needs the date too. GGA doesn't have date info.

I agree that one doesn't see ZDA used very often but that seems to be the one the radio designers adopted, perhaps because it also allows for Local Time Zone Offset and they use it around the NMEA network for synchronizing other gear. They could have helped the broader spectrum of integration if they also supported RMC. My Nav6+ has NMEA display modes which support RMC, GGA, GLL and ZDA for Time and RMC and ZDA for Date. In each case they use the data in preference from left-->right as I have listed it. Very good.

My guess is that if there is no GPS info the DSC alarm message would be in UTC time as I understand that is the 'reference time' for worldwide rescue work. There is a mode to send a test message but I haven't explored that yet.

BTW, if your lithium battery dies, you can get 'tagged' versions of the CR2032 from electronics suppliers to solder in. I hear Maplins is a great source, you could check their website.

It is a bit sad the amount of time 'wasted' on this but it is also an interesting diversion for me. It is winter here and raining cats & dogs as I type, so I am enjoying the chase - and learning something too.

 

[Plevier]

Had a play today.
With radio on and GPS not turned on, pressed tel/DSC button and scrolling display obviously had no position but also had no time either so assumed memory battery had gone.
However turned GPS on and a time display appeared - but not read from the gps but from internal clock, could tell because of slight difference. So why wouldn't internal clock display with GPS off?
Had a look inside the unit to see what type of tagged battery needed - on edge or flat - to find not a soldered tagged battery as per the manual but one in a socket.
Checked its voltage, just over 3V so obviously OK, put it back.
Investigated GPS setup - no way to select which sentences.
I'll have to live with the internal clock and keep an eye on it.
At least I know how to operate it now!

 

[Gypsy]

I think that when there is no GPS (lat/lon) the software switches to manual entry for all elements (lat/lon/time/date) and therefore they do not display it on the 'DSC' bottom line crawl.

The only way out now is to ask Thrane & Thrane if there is any software/firmware update for the radio which would allow it to extract time/date from another NMEA sentence such as RMC. Perhaps you could contact them direct. The guy I spoke to here didn't offer any upgrade but the company is a dealer not a local T&T office. Perhaps the T&T factory has other info.

Good luck. We all know more now than when we started so that is a plus.

 

[Plevier]

Ahead of you for once - emailed T&T and Interphase a few days ago!