NASA Navtex Engine

duncan99210

duncan99210

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The damage to the ICS Navtex Antenna being terminal and the cost of a replacement being silly, I've been scratching round for an alternative. One idea is to fit the Nasa Navtex Engine (which is quite a lot cheaper than a new antenna). Does anyone have any experience of this bit of kit? Is it any good? Opinions appreciated.
 
I don't have one, but I've seen a lot of posts about it here. Summary seems to be that it's nothing like as good as the ICS, some people are happy with theirs, some have lots of problems.

I've been on a couple of charter boats with one fitted, and found it hard to understand and fiddly to use compared to the ICS sets we used to have on the Army boats. I guess you'd get used to it in practice.

The different model of NASA navtex that came with our old boat could only receive one frequency at a time - there was a physical switch in the antenna cable to choose between them. So in UK waters you couldn't get both inshore waters and main service without flipping the switch at appropriate times. I don't know if the Engine is the same, but it may well be as I think they use the same antenna.

Personally I have no need for Navtex at the moment, but expect to in the next few years. When the time comes I'll be buying the ICS.

Pete

EDIT: Just realised I was thinking of the NASA standalone units when writing my second paragraph, not the Engine that plugs into a laptop.
 
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I have one & seems to work fine. Software a bit clunky but it works, takes a while to transfer messages over usb/serial adapter - com port is much better. Attached to insulated backstay when used so reception pretty good, handy to know what's going on down in Algeria :)
 
I have a NASA NAVTEX engine connected to my Standard Horizon plotter. It works OK with no problems. The aerial is on the pushpit. I don't find the NASA software awkward, choosing the stations you want to receive is just a matter of changing their identifier letters from lower to upper case - just a keystroke.
 
There really is no reason why the NASA NAVTEX engine should not be as good as any NAVTEX receiver. Remember that NAVTEX is not intended to be used in harbour where it may or may not work.

I always have problems with the concept, but I am a yachtsman and do not have the power supplies sufficient to keep a PC going except in short bursts. That rather reduces the value of AVTEX which is designed to be left on at all times. Also, in foul weather, the laptop is kept in a safe, dry environment. I ruined one with water dripping on the keyboard. Fine for a motorboat with plenty of power. Not for me.

With the Internet, many people find that they do not use their NAVTEX very much. To me, it has three factors that make it a “must have.” First, if over 30 miles out it will probably be your only source of MSI. Secondly, it is a relatively painless way of getting NAV warnings – especially when abroad. Thirdly, it is a back-up when all else fails. Just occasionally, we have found ourselves with no VHF, no internet and no useable cell phone contact.
 
franksingleton said:
I always have problems with the concept, but I am a yachtsman and do not have the power supplies sufficient to keep a PC going except in short bursts. That rather reduces the value of AVTEX which is designed to be left on at all times. Also, in foul weather, the laptop is kept in a safe, dry environment. I ruined one with water dripping on the keyboard. Fine for a motorboat with plenty of power. Not for me.
Click to expand...

The nasa navtex engine only draws something like 30mA so power not really a problem. It stores the messages even if you turn the power off, just attach a laptop to view the messages . You still need a dry laptop though :) I find it useful as otherwise it would just be another screen to find some space for at the nav table.
 
Yes, the NavTex engine remembers a large back-log of messages so you only need to turn a PC on to read the latest ones. I have one and fitted the aerial inside a locker just under the deck at the stern. Reception seems fine at sea but is often rubbish in harbour, but that's not unusual for NavTex.

The software is rubbish as has been mentioned. It looks as if they asked someone who dabbled a bit to knock something up in an afternoon. I keep thinking about writing a proper interface but never find the time.

The engine only listens on one frequency at a time and you program in changeover times (2 changes each day for channels A & B). You can also filter messages to avoid clutter from unwanted message types.
 
Works exactly as described above. I have the antenna under the side deck in the dry (also avoids routing the cable to the stern!). It still receives all the 'local' stations around northern Europe.

I find it much easier to filter the messages on the laptop and read just what I need. The full set of messages are all still there (for maybe the last 60 hours) so you can always refer back if needed.

For something that is only used occasionally it provides exactly what I need. The ICS or Furuno units are just too expensive to be justified IMHO.
 
Slight drift..

this came in last night, nasa engine attached to insulated backstay, boat in Limehouse - would this have been rebroadcast from somewhere closer to home or did it make it all the way from the Med?

>RA61
120250 UTC FEB 13
LA MADDALENA RADIO
COASTAL WARNING 059/13 FEB 09
TYRRENIAN SEA CENTRAL EAST SECTOR - VENTOTENE ISLAND.
SIGHTED LIGHTHOUSE I.L. 2286 (E1592) VENTOTENE ISLAND
IS OUT OF ORD
ER.
IN ACCORDANCE WI
TH GAETA PORT AUTHORITY'S FAX NR.198
DATED 09 FEB 2013 TRANSIT SHIPS BEWARE.
a0
<
Click to expand...
 
Conachair said:
The nasa navtex engine only draws something like 30mA so power not really a problem. It stores the messages even if you turn the power off, just attach a laptop to view the messages . You still need a dry laptop though :) I find it useful as otherwise it would just be another screen to find some space for at the nav table.
Click to expand...

It is not the power drain of the engine. A "proper" NAVTEX set has a small drain. It is the power of the PC necessary to view the messages. OK witha large boat and plenty of power and, maybe, a built in computer. Not OK with a small boat, limited power and wanting always to be able to read the NAVTEX without having to open up the PC.
 
franksingleton said:
It is not the power drain of the engine. A "proper" NAVTEX set has a small drain. It is the power of the PC necessary to view the messages. OK witha large boat and plenty of power and, maybe, a built in computer. Not OK with a small boat, limited power and wanting always to be able to read the NAVTEX without having to open up the PC.
Click to expand...

Well, I can see the argument about the chance of a laptop getting wet on a small boat but power isn't really that much of a problem, I just booted mine up (12v PC) , took 4 minutes, switching on, reading last few messages. Not much going on, fishing boat lost nets off Guernsey, Sandeti nav aids not working. Then off again. Say 3A & 10 mins for a leisurely read that' still only 0.5Ah, not much really.
Not sure how others use it but I would probably have a look at it before setting off then maybe on a long offshore passage out of boredom as much as anything. Weather offshore comes more from weatherfax, though that's most likely more habit from cruising further afield where navtex is too unreliable to help much.
It does come into it's own round Europe though, for nav warnings & lights out etc.

Just noticed http://www.frisnit.com/navtex/ do an auto email service, which might come in handy for those without a receiver but with a smart phone. I'm not sure if all those nav warnings find it onto the web otherwise. :cool:
 
Conachair said:
Well, I can see the argument about the chance of a laptop getting wet on a small boat but power isn't really that much of a problem, I just booted mine up (12v PC) , took 4 minutes, switching on, reading last few messages.
...................

Just noticed http://www.frisnit.com/navtex/ do an auto email service, which might come in handy for those without a receiver but with a smart phone. I'm not sure if all those nav warnings find it onto the web otherwise. :cool:
Click to expand...

I am paranoid about water on the keyboard, having had the experience.

Yes, I could use hibernation but what a palaver. It destroys the concept of NAVTEX automatic operation. For anyone unable to have a PC running whiles ailing, the extra cost of a “proper” NAVTEX over the engine is surely worth the cost.

I have watched and had a link to http://www.frisnit.com/cgi-bin/navtex/view.cgi for some years now. It has always been rather hit and miss. Look for Cullercoats, Portpatrick, Malin Head and Valentia.
 
franksingleton said:
I have watched and had a link to http://www.frisnit.com/cgi-bin/navtex/view.cgi for some years now. It has always been rather hit and miss. Look for Cullercoats, Portpatrick, Malin Head and Valentia.
Click to expand...

Now why is all this stuff not promulgated through the web as well? Works with notices to mariners, seems odd that a service for transmitting information doesn't use an easy medium like the web :confused:

Just noticed the map page of that site - http://www.frisnit.com/cgi-bin/navt...0906e35d349374a5bd2ad&offset=0&map=fullscreen
 
The site is simply an adverts for a NAVTEX decoder. It is not an operational MSI services. It fits where it touches – just.

Regarding what is available on the Internet. It is a mess. For NAV warnings, there is http://www.iho-ohi.net/mtg_docs/com_wg/CPRNW/CPRNW_Misc/RNW_on_the_web.htm but the format varies greatly between NAVAREAs.

For Weather, there should be NAVTEX messages at http://weather.gmdss.org/index.html . There are all the available High seas INMARSAT-C broadcasts. Some areas have NAVTEX as well but by no means uniformly. Météo France made a good start but did not seem to carry the idea to its logical conclusion. When I last had contact with them, they were obsessed by the notion that old texts could be in cache and be misleading. It was with some effort that I persuaded them to allow the links to be bookmarked.

Texts of NAVTEX broadcasts can usually be found on National Met Service sites but it is a variable feast. Met Services and marine authorities generally have not really come to terms with the use of the Internet for MSI. The wheel is being invented many more times than necessary.
 
I'm afraid I disagree with Frank's earlier comment on their being no difference in reception qualities of different NAVTEX receivers. Because PC Navtex supports most NAVTEX receivers, we test across the board quite often on everything from big ship SOLAS receivers to NASA budget models. This is done sequentially for about an hour at a time, so no difference due to reception conditions. Quality of reception (i.e. smallest numbers of characters replaced with * and best reception from distant stations) does seem to correspond to price, with SOLAS receivers best (I suspect due to better antennas) and NASA at the bottom. But the question should really be is receiver x good enough for my purposes - if you just sail close to a single transmitter then you don't need as good reception as somebody sailing well offshore and traversing several coverage areas.

Seperately, the La Maddelena message did come all the way from the Med, probably as a sky wave (i.e. bounced off the atmosphere, unlike normal NAVTEX transmissions that are ground waves that follow the earth). This is not uncommon at night, and using the backstay as an antenna would make a big difference to your receiver.

Tim
 
I have no experience of SOLAS standard sets. I have used the NASA PRO and the Furuno 300D dual frequency set. I have been alongside other yachts with a variety of receivers. My comments were based on knowing that other boats had or had not received what I had received. I cannot say what the error counts were, just that messages were received and understandable or not as the case might be.

Obviously, I could not do the detailed test that Tim has done. All I can say is that there seemed to be little difference between what was received on the various boats. In some ways the NASA software was superior to the Furuno; certainly it was more forgiving when there were minor formatting errors. I also found it useful to be able to see what was being received. That facility is not available on the Furuno. The build standard was higher on the Furuno; the NASA screen was more difficult to read and, after some 10 years or so stopped working.
 
If anybody from NASA reads this, I would really like a Navtex engine that can broadcast messages to my iPad.
 
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