Tuesday, 3 February 2015

There must be 50 ways to track your sailboat...

Well I am not sure there are 50, but there are a lot of ways to do it now. Of course there are Satellite based services you pay for with a subscription. These use the same Satellite networks that sat phones use (with the same coverage) Yellow Brick and Spot are best known, also inReach from DeLorme, some Sat phones also have a built in ability to send position reports. What I am interested in is ways to do it without a subscription.


AIS


If you have an AIS transmitter on your boat then web sites like MarineTraffic will display your position when you are within line of sight range of one of their receivers on the coast.  If you have a class A AIS transmitter Marine traffic may be able to track you away from the coast by picking your AIS signal fro a Satellite. But class A AIS systems are more expensive and you need to pay for a subscription to Marine Traffic to see satellite reports. Here are some of the AIS monitoring web sites with (hopefully) a link to Tui.


    • PortMaps this is a German site but has a nice feature of showing the position on a Navionics Marine Chart
    • APRS.FI This Finnish site is not for profit and run by radio amateurs but it does show you the AIS position for any date, however it does not yet have an extensive receiver network. It also tracks Amateur Radio call signs


HF Radio/PACTOR

The Hf (high frequency) radio, is usually called SSB by boaty types, but it does not just use Single Side Band (a type of modulation for voice) but can also send digital signals.  On Tui we use a PACTOR modem connected to the ships ICOM 710 marine radio, or my Ham radio.
  • Winlink (email etc over amateur HF radio) may have a position report associated with my ham radio call sign M0WLH. Usually a position report is sent when we connect to send or receive email or download a GRIB weather map. 
  • We may be able to send position reports to Yotreps over HF radio  as well. On that site we use the call sign MRGV9.  It will show "No Reports" if there is no recent position report.
  • Yachttrack is another web site that gathers position data. It currently says we (M0WLH) are hanging out near Panama with a lot of other happy yachts having a winter party. This is because I was testing the PACTOR modem at home and that must be the default location for OpenCPN/Navigatrix when there is no GPS connected. Oops. A link there for M0WLH goes to positionreports.de where you can see our amazing transatlantic virtual voyage.
  • APRS.FI also picks up ham radio call sign reports, but see APRS below 

APRS

APRS (Automatic packet reporting system), is an Amateur radio tracking service.  Mostly radio hams send position reports using 2m (VHF) radio including small (cheapish about £100) portable beacons, or a thing called a TNC (Terminal Node Controller basically a modem) connected to a 2m ham radio (which could be a hand portable or vehicle type).  There are Android apps that work as a TNC when connected to a radio using the sound output, and they can also send position reports over mobile internet.  APRS.FI picks up  most of these reports associated with the amateur call sign. There is an extra character that is meant to indicate the type of station (which comes up as an icon on maps). Eg Y is a yacht.  My PACTOR modem can also work as an APRS position beacon. You can just connect a modem to terminals on the back, type a few commands over the serial line and away it goes. If it is connected to an HF radio it will need to be able to get to an APRS gateway and I suspect that there are not many of those around in Europe but lots in N America. Also as HF goes so far it wouldn't take many stations putting out regular position reports to swamp them. APSRS can also be used with amateur radio satellites using VHF (but right now there are not that many working ham radio satellites).

Edit: I have just found a video of a yacht using APRS over HF to track its voyage in the N Atlantic.
Ultimate3 on a breadboa

WSPR

WSPR ("Whisper") is a ham radio digital protocol used to study the propagation of radio waves. With HF the signal bounces off the ionosphere and different frequency bands will go a different distance at different times of day. When using Airmail to send your email using a PACTOR there is a nice tool that tells you what the probability is of reaching each of the nearby relay stations on each band. WSPR typically uses very low power HF radio beacons which transmit a simple message with the position, call sign and power used using a very robust protocol. The position is given using a 4 character Maidenhead locator. A grid square in Lat and Long. Fortunately an extension of WSPR gives the 6 digit locator, this gives an accuracy of 2.5' of latitude by 5' of longitude.although the message takes longer to transmit. This is accurate to within about 5 or 6 nautical miles. Inspired by Robert Kraowski's success, transmitting his position from a yacht off Fiji and having it picked up in Finland and Greece I bought a kit for the same beacon. The Ultimate3 beacon by QRPlabs. This little kit costs $29US and uses about 200mA.
I tried to assemble mine over Christmas but it was just on the limit of my soldering ability. All the surface mounted parts are pre assembled but I managed to fry a couple of tracks. It is currently working but on a breadboard. The user community, and Hans Summers who designed the kit are incredibly helpful and the instructions are comprehensive. Just make sure you practice with a fine soldering iron first.





The map shows stations that received my signal from home the first time I got it working. The range from about 700 to 2000km away, and this is using the 20m band, 14.097MHz. For a nice tool that gives what to expect on propagation see voacap.

[I will update this when I have it soldered on a PCB and in a box!]


Here is my Ultiamte3S all nicely soldered on a PCB

Thanks to Jim Fairhurst, fellow member of Buxton Radio Amateurs, for an evening teaching me to solder better in which we made the kit up.  It is currently being tested on a 5m fishing pole whip antenna in the garden.  It has been heard up to 2100km away, furthest so far is Haifa in Israel.





The U3S and an old MFJ manual antenna tuner are in a waterproof laptop bag (that I got from a fishing tackle shop). There are three 5m wires laid out as "radials".  On the boat I am planning a smaller manual antenna tuner and a Kevlar reinforced wire to the spreaders.   To set it up I used a Sark antenna analyser.









Monday, 2 February 2015

Sunday, 1 February 2015

Tui goes through the Swellies

This is a slide show of Tui Launching at Dinas boat yard at Y Felinheli in March 2013 and going through "The Swellies", a notorious narrow rocky part of the Menai Straits (between Anglesey and North Wales).

For sailing directions I recommend The Caernarfon Harbour Trust's excellent pilotage guide . The main trick is the timing of leaving with respect to slack water, and memorizing the leading marks
We were nervous as this was Tui's first voyage after I bought her.