Rod Heikell's very informal site on sailing around bits of the world and an eclectic collection of things nautical or nearly so.





Some tips on Single Side Band marine transceivers and Pactor modems from a self-confessed radio nerd.


I’ve only been using an SSB for a few years, and not really that much until this last year. I though it might be interesting to pass on some of my new-found knowledge to others joining the twilight world of long range radio communications. Much of what is written below is knowledge gained from experience, much is also gained from a number of kind and helpful experts and professionals, who I list at the end, and to whom I’m extremely grateful.


Advice may be found from many sources, but I have sometimes found it difficult to decipher some of the ‘radio speak’ into a language I can understand, at a level which is enough to be useful, but not too much to overwhelm. There are many experienced radio amateurs or HAMS who you’ll meet who will give their time and expertise freely. But beware the ‘expert’ who can really mislead you. How do you tell the difference? Well, maybe after you’ve read this you’ll be in a better position to judge. This is intended as a brief introduction for people thinking of installing a long range radio, or for those who have one but would like to get a bit more out of having it.













  1. To hear voice weather forecasts or to have communications with ships or coastal radio stations for safety or distress purposes when out of VHF range.
  2. To keep in touch with other yachties while on long offshore passages.
  3. To send and receive short emails, send position reports or blogs while on passage with no ‘online’ charges.
  4. To obtain text weather forecasts, weatherfax or Grib files while offshore.




  1. If you don’t intend to make many long offshore passages. For the odd long passage a hired satellite phone may be better.
  2. If you want to be able to have high speed internet access, and to send large files and photos while offshore – a state of the art satellite system is the only thing to have this sort of capability.




Some people will have ‘inherited’ an SSB which is installed on a yacht you have bought. Buying new is a bit of a minefield in the EU, since many radios are not licensed to be sold in the EU, but marine SSB suppliers will have several options. Popular ICOM sets are the M700Pro, M710, M801 and the M802(DSC). These all have email capability as well as all the usual radio facilities. Most people buying new will need some professional help to complete the installation. In addition to the radio you’ll probably have an Antenna Tuner Unit somewhere in the lazarette, linked to an insulated section of the backstay as an antenna, or to a whip antenna.


  1. Grounding your SSB system. Our SSB is grounded via the tuner to two dynaplates, via 8AWG wire. (It should really be copper strip, but I couldn’t get any at the time. I’ve since discovered that this is ok for the sort of max power we use – up to 150W – although copper strip is always better). Note our SSB is not grounded independently.
  2. The Antenna. On other boats I often see the cable joining the tuner to the backstay neatly cable tied tightly up against the backstay. It shouldn’t be. You lose loads of transmission power if you do this. You can buy very smart spacers to hold the cable off the backstay, but I made my own using short lengths of polypropylene pipe to do the same job. The cable needs to be held about 6-9cm (3”) off the backstay (or any other big chunks of metal come to that); you’ll need around half a dozen bits of pipe. Drill a hole in one end of each of the pipes and thread the cable up through the holes. Then secure each pipe onto the backstay at suitable intervals using a long cable tie. Loop it around the cable, through the pipe and around the backstay. Secure the end of the cable to the backstay using self-amalgamating tape.
  3. Wiring. Keep the power cable as short as is practical, and if possible take them directly to the battery, and not through the main switch panel. The radio is fused and switched anyway, and is much less likely to suffer or cause interference than if it is wired through the main panel.





Just like a big VHF? Well no, not really. Users need a Long Range radio licence to operate an SSB. You need a working knowledge of common operating frequencies for ship to ship, ship to shore or shore to ship. You also need to remember that you are often transmitting over a very long distance. Yes, you can use the radio to communicate with fellow yachties, but it is usual to pre-arrange a frequency and a time or schedule for calling each other. Transmitting on SSB demands a high draw from your batteries. SSBs are intolerant of voltages much under 13V, and for most of us this means you need to either run the engine while you transmit, or at least to have fully charged batteries before you start. If you don’t, your transmission will be garbled at best – think of an old 45 record played at 33rpm – and usually unintelligible.

We use the SSB to listen to MF/HF weather forecasts, radio nets and informal nets and scheds with friends. Details of frequencies used for weather forecasts and many nets can be found in Almanacs, Pilot Guides or in ALRS Vol 3 (NP283).





Talking to other yachties in harbours and anchorages you’ll find out whether there are any nets running in the area. Some of these are very useful ways of keeping in touch and sharing weather information, like the Westbound Atlantic Cruisers’ Net. This net was set up for the 2007/2008 Atlantic crossing season by a US yacht (and it is almost always an American; they seem to be naturals when it comes to radio nets). Anybody can join, by listening at the pre-arranged time, and following instructions given by the ‘net controller’. This type of net usually follows a pretty standard procedure. The net controller opens the net, giving the time and frequency used, and a brief outline of the purpose of the net. They then invite anyone with emergency traffic to broadcast. There is then often a brief weather forecast, and others may be invited to contribute to this. Then they open the net for any yachts wishing to check in to broadcast their boat name in turn. The net controller will then call each yacht back by name, and requests basic information such as position, number of people on board, last port of call, next port, your wind, wave and weather report and any other useful info. It is a great way of staying in touch with others making an offshore passage, and should you encounter any problems on route, you have an opportunity to let others know what is happening, and whether you might need any assistance. The net will also be alerted if for some reason you do not check in at a later date. If a yacht misses check in then the other nearest boats will be alerted, and they may then be able to try to contact that vessel by other means.

It is normal for the ‘net controller’ to rotate between other yachts in the net, to share this time-consuming task, and  in order to keep the net running after others arrive at their destination. People seem to be reluctant to volunteer for this, but as one who has done it, I can thoroughly recommend it. Yes it’s a bit nerve-racking the first time, but it’s actually fun; you’re taking your turn to help keep it running, and just remember, everyone else is really happy that you are doing it, and wants to help.





With simple software and a laptop with a sound card you can also receive weatherfax, although I have to admit I never had much success with this, though it works for many.


We decided to add a Pactor modem to our set-up to enable us to send and receive small emails while out at sea and out of range of mobile communications. Here are some considerations when setting up this system:


  1. You will need a well installed SSB radio with data capability, a windows based computer to run the software, a Pactor modem and lots of cables.
  2. Depending on which radio you have, you may be able to set up the system so that the modem can remotely tune the radio to the necessary frequencies. This makes a huge difference to the ease of use, and if you are buying a new radio for data purposes, then this should be a consideration. Most modern sets do have this capability, but check if you are buying second hand.
  3. Consider the laptop pc you will be using to run the email viewer on. Due to our smallish chart table and its slightly exposed situation, we decided to buy a second-hand tablet pc which is small enough to sit on a shelf, has a shock protected hard drive, and does not store other important stuff on it like documents or photos etc. It cost around £160 on Ebay and runs MS windows 98. It has a serial port and USB ports, and a 12V charger. We also use a USB mouse and keyboard (also from Ebay) instead of the touch-screen controls for ease of use on a bumpy passage. Our main laptop with all our other stuff on it is available as a back up, but we’d rather not use it when underway as the chart table is potentially exposed to rogue douses of seawater slopping around the sprayhood and down the companionway..
  4. SCS Pactor II modem with Pactor III capability is the latest model available. It can come with either serial port or USB connection to your computer. Most modern computers don’t have a serial port, and I chose the USB version as it meant I could easily use it on any laptop if the tablet pc failed for any reason. If you have a serial port Pactor you can get USB convertors, but this gets complicated as they can interfere with the radio. The Pactor III using Sailmail (see below) can send and receive emails up to around 10kb in size. Yup, that’s 10kb; about 2 pages of plain text. Very few attachments can be handled. And you can forget about photos. If you need more than this then you are going to need some sort of satellite communications system, which is not covered here. A SCS Pactor IIusb Modem with Pactor III costs around £650 new.
  5. Consider buying the Pactor from a professional radio supplier – they will be able to help you set the system up, provide all the necessary cables, and will often ensure the system is working properly before you set off. I bought ours from Bob Smith at Sailcom who was able to set up my system and test it using one of his radios – similar to mine – as our yacht was in Greece at the time. He managed to solve an obscure software driver problem that would have stumped me, and thanks to his help, I was able to plug it all in on the boat and get it running with no problems. Of course you may be able to pick up a used ‘bargain’ on Ebay or elsewhere, but there is no guarantee that it will work, and unless you can test it quickly you will have little chance of redress. You will also need to get the fairly specialist cables made up to connect it up to the radio and the laptop.
  6. You will need to sign up to an email provider in order to send and receive email. Sailmail is the best known, with the greatest number of worldwide radio stations, and is the one we use. If you are a radio HAM you also have the option of using Winlink, but you need an amateur radio licence to do so. Annual membership of Sailmail currently costs $250.
  7. You’ll also need to download a messaging program (similar to MS Outlook) – we use Airmail – onto the laptop you will use to connect to the radio. Airmail is designed specifically to work with low speed connections such as radio or satellite phone, and is licensed without charge to the amateur radio community, and to Sailmail subscribers. It is pretty straightforward to use, and has excellent online instructions on the website. Airmail also has excellent facilities to obtain weatherfax, Navtex and US Sitor forecasts, all of which I have used with near perfect results. In addition, part of the email message program has a built-in form for position reporting from Yotreps or Sailblogs. Another great part of the Airmail program is the email-based document-retrieval program Saildocs. Using the Saildocs-friendly part of the Airmail program you can easily request custom Grib files, text weather files or web pages. You can also set up a subscription to receive regular forecasts. This system has a massive advantage over some other similar services as the complex formatted requests are auto-formatted using the Airmail software. It has a simple Grib viewing program. Oh yes, and they even have a propagation program to help you decide which Sailmail station is best for you to connect to at any given place and time. It really couldn’t be easier.  I’m not going to go into the real nitty gritty of Sailmail, Airmail and Saildocs – they have been developed by an amazing dedicated bunch of people with an enormous amount of experience, and they are incredibly generous in sharing a huge amount of knowledge on setting up these systems to work with your equipment. They give advice on choosing a Pactor modem, which radios are compatible, how to improve your grounding system, what cables you’ll need. In short, all I needed to know I found on their websites. I would never presume to propagate their wisdom as my own, although I do try to live my radio life according to the Sailmail Primer!
  8. You can also link your Pactor modem to your GPS so that the Airmail software ‘knows’ where you are. It will automatically fill in your position when sending position reports and will help when selecting an area for Grib files or text weather reports. It also means the propagation program knows where the nearest station is. All you need is a length of speaker wire to run from your modem to the NMEA output of your GPS. (Ours is also linked to the DSC VHF with no problems).

Tablet PC bought on Ebay that can handle everything a steam powered modem will throw at it.





So, you’ve got your shiny new Pactor modem, your laptop with programs downloaded (and backed-up somewhere) a bunch of cables and a compatible radio. You’ve plugged it all together and fixed it all down so it doesn’t all slide around at sea. You’ve joined Sailmail (or another service) and you’ve read all their instructions.


Hopefully it has all gone smoothly, you fire it all up and start to use it – and it all works –fantastic isn’t it!

No? Well I’ve seen a few set-ups on other boats where it wasn’t, and I’ve a few tips that I’ve found to help to get things working.





1.  You can hear people, but they can’t hear you?

Check you don’t have any fans running – even less obvious ones such as in the fridge, the engine room, in invertors or even that one blowing gently onto you from above the chart table.


2. You can’t select the voice frequency you want to use? 

a.    First, double check it is a valid marine voice frequency for your purpose ie ship to ship or ship to shore.

b.    Some ICOM radios are ‘locked’ as a default. Visit the ICOM website where there is a very useful knowledge base. You will probably find the solution there. It usually involves turning the radio on while holding down a couple of other keys.


3.  How do I get started with SSB voice transmissions?

a.    First try tuning in to weather broadcasts from coastal stations. Try Monaco Radio on 8728 or 13146 kHz (ITU Ch 804/1224) at 0930UTC.

b.    Try to arrange an informal sched with another boat. Remember to always check before transmitting for any other traffic, and always sign off with your callsign. Some commonly used frequencies are 8104, 8107, 8122 kHz.


4.  You can’t connect to a particular Sailmail station?

a.    Re-read ALL the Sailmail notes.

b.    Check the propagation program to see whether it is a suitable time.

c.     Is it a station with a single transceiver – if so it might be busy on another channel.


5.  You hear lots of ‘chirping’ and ‘rasping’ when you are waiting to connect?

It takes a bit of time to get used to which sounds are ‘real’ connections and which are just interference from other stations. Just persevere and you’ll get to recognise which are which.




6.  Your computer locks up and loses connection with the modem when trying to connect to a Sailmail station?

a.    It’s probably caused by stray RF interference. Make sure you have ferrites on all relevant wires. Re-read the Sailmail advice on minimising RF interference.

b.    Try to keep as many wires as possible away from the area around the computer.

c.     Try moving your computer away from the radio – if possible ‘sheltered’ by a bulkhead.




My thanks to everyone who has helped me to advance my nerd-dom: especially my husband Rod who patiently sails the boat while I’m glued to the radio before emerging triumphantly with a new Grib file or email. Also Bob and Claire Smith at Sailcom, Stuart the marine electrician in Florida and Andy O’Grady.



YachtCom radio training courses Tel 01489 565100

Sailcom Marine Communications equipment






Weather for Ocean Passages

Weather for Ocean Passages

We are all now accustomed to fast broadband internet connections, with myriad options for obtaining weather forecasts over the web, but once away from a wifi connection, getting good weather info gets trickier.

In the main collecting points for ocean passages, be it Las Palmas, Lanzarote or Tenerife in the Canaries for Atlantic crossings, or Panama at the start of the Coconut Milk Run, it is easy to get connected to wifi for as much passage planning weather as you like, and below I list a few of our favourite sources for the bandwidth rich:


A familiar and easy to navigate site with sensible map scales for graphic forecasts. Also has synoptic charts.

Passage Weather

Good clear graphics and a good range of chart areas.

Grib US

Download the free grib viewer and sign up for a free account and you can get 7 day grib files on demand.

US National Weather Service

Had to mention this as an excellent all-round weather info website with great links to other sources.

Jcomm Weather


A text only site in English, maintained by Meteo-France, giving the official forecasts for each MetArea. As text only it also works well for the bandwidth impaired.

MetArea Issuing Auth Area covered

II France NE Atlantic to 35°W and down to 6°S

IV USA NW Atlantic from 35°W and down to 7°N

XII USA NE Pacific down to 3°24S and across to 180°(Panama to Galapagos)

XVI USA E Pacific from 3°24S-18°21S, Peru to 120°W

XIV NZ SW Pacific (Marquesas to Fiji to NZ)

For a detailed map of world Metareas there is a link on the Jcomm website.

Internet Weather Sources for the Bandwith Impaired

Once out of wifi range, links to the internet are, unless you have a large satellite dome and almost unlimited funds, severely limited.

This usually means access is limited to satellite phones with hefty data charges, or SSB with a Pactor modem. Both have their advantages, but they are both limited by the connection speed, which makes the old dial-up speeds look good. In any case, surfing is out of the question, so most of us rely on some form of data retrieval from certain websites, and having it sent to us as an email. This can be done using several systems, but most depend on a strictly formatted request email in order to carry out the correct instruction. Get one character or space wrong, and you will receive nothing, or an email of gobbledegook. Some programs get around this by giving you a request form to fill out, which makes things much easier. The important thing to remember is that you are sending an electronic request – if the link, or any part of the request is incorrect, it cannot be delivered. This includes any typos, or any web address changes you are unaware of. The request must be sent in Plain Text Format, not in HTML. Many email providers, like Yahoo, default to HTML, and you need to change your settings to plain text. Likewise if you send through a portal like MS Outlook or Mozilla Thunderbird. Others like Airmail default to plain text so you won't have a problem.

Some national weather services allow free access by FTP (file transfer protocol) to their weather info, and if you are reasonably proficient with a computer, you can follow the instructions on the various sites to get what you want. It is probably best to start doing this at home where you can figure out the requests you'll need in advance. The US NWS link below is probably a good place to start.

We use the following services to get weather info, be it text or grib forecasts, sent to Skylax via a SSB and Pactor modem, with a subscription to Sailmail.


You can ask for one off forecasts, or 'subscribe' for a daily forecast for as many days as you want. Bare in mind it is easier to increase the subscription than keep getting a build up of requests that you do not use.

Fantastic document retrieval system which uses the Airmail platform for very simple forecast requests, as part of your Sailmail subscription Airmail is also available to users of the HAM Winlink service

Note, without Airmail you can still use this free service but you need to format your own request.

Airmail has a worldwide catalogue of text forecasts from each MetArea issuer, and you just click the box on the one(s) you want. To request grib files you use a map to highlight the area you want, then fine tune the detail – data grid,wind/wave/MSLP/rain, and even opt for a moving forecast so that you don't need to highlight the whole of your passage area – just a certain amount, and then each day's gribs shift along your course, at your speed. It's really clever, and really simple. I love it!

A good read of the Saildocs info, and you'll find you can get virtually anything sent to you, size and graphics permitting. And it is specifically geared to the bandwidth impaired, so you don't get any files too big to deal with.


A subscription service (US$70pa) that gives a range of services, including 7 day virtual buoy forecasts, and passage forecasts for projected positions for up to 5 days. Uses a variety of source data, and we know lots of people who swear by it, even for tough forecast areas like the Red Sea or the Mediterranean. You need to format your request very carefully, as it is in text format.

Other weather by email services:


Access to gribs, text and synoptic forecasts. Provided free as part of email compression subscription service geared towards sat phone users.

Global Marine Net

Limited grib service outside many subscription services for sat phone users.

US National Weather Service

Great source for all US, Canadian and some UK forecasts. Text and synoptic charts available.


or in English

FTP access by Meteo-France for text and satellite images, and for grib files by subscription.

What to Request

Aside from grib files, the most common requests we make are for the regional text forecasts for the area we are in. The FTP codes for these forecasts vary depending on the service, but you will easily find them under the 'help' document for each service. They were handy to get a meteorologists view on the weather, which helped to explain what you were seeing on your gribs.

Occasionally, when reception was good on the SSB, we would also request the BBC news frontpage, low graphic version, for a low-down on world news.

For the trip across the Pacific, we also subscribed to Bob McDavitt's Weathergram, a weekly view of weather across the Pacific from the NZ Metservice 'Weather Ambassador'. For details of how to subscribe, see

Click on Mail Products.


Other Weather Sources using HF Radio


Using the SSB, and a laptop with appropriate software, you can download synoptic charts while at sea, at no cost. Using the Airmail software as part of the Sailmail subscription, the GetFax will automatically tune to the station of your choice, and auto start the download. You can even set up a timetable to switch between different frequencies or stations to record different faxes or text forecasts at certain times, automatically.

Frequencies and schedules change, so I'm not going to list them here – see a current Almanac, or go to

Roughly speaking, these are the stations we used:

E Atlantic – Northwood

W Atlantic – Boston

Caribbean – New Orleans

E Pacific – Pt Reyes

S Pacific – Honolulu

SW Pacific - Wellington

Sitor/RTTY text forecasts

Again using Airmail software, but also available using a dedicated receiver such as the NASA Weatherman or NASA HF3, or some other laptop based software. RTTY forecasts for the N Atlantic and Mediterranean are available from DWD (German Weather Service) Hamburg and include a five day outlook which can be useful for planning longer trips. SITOR forecasts for US waters are available from Boston, Pt Reyes, Honolulu & Guam.

Frequencies and Schedules are available from: Use the search window for 'rtty'

Radio Nets

The numbers of yachts doing ocean passages with either a sat phone or SSB-Pactor modem combo probably outnumber those who don't, but it is by no means a pre-requisite. At any of the pre-crossing hubs, mentioned above, you will find knots of yachties discussing which 'net' they will be using. Schedules for these unofficial nets won’t be found in any of the Almanacs or glossy brochures. It’s strictly word of mouth. It’s not because anything is secret or limited to a few in the know, it’s simply that nets come and go with the seasons and with the people who are running them, and you just need to listen around a bit at the watering holes to find out the current schedules. Americans in particular are wonderful at starting up a net, and as word spreads, the number of participants grows, sometimes reaching forty odd yachts at any one time.

Once you know what frequency and time they are on, you have access to a host of weather information. It is normal for each yacht to give the actual conditions where they are. Quite often on these informal nets someone will give a brief weather forecast, but even if they don't, if you join the net, you will find a willing voice to give you any weather info they might have.

Informal net frequencies change, but may be:

Atlantic: 8104/8107kHz at 0800UT

Pacific: 8143kHz at 1600UT

Formal Nets:

Med Net 8122kHz at 0630UT

Maritime Mobile Net 14300/14313 24hrs (HAM net)

Herbs Atlantic Net 12359kHz 2000UT (check in from 1940UT)

Caribbean Net 8104kHz 1215UT

Pacific Maritime Net 21412kHz 2200UT

Pacific Seafarers Net 14300kHz 0230UT (HAM net)

Coconut Net (Fr Poly) 8188kHz 1730UT

Coconut Net (SW Pac) 12353kHz 1830UT

Rag of the Air (SW Pac) 8173kHz 1900UT

Of course, having all this information won't guarantee you the weather you want, and since we are not in the same league as the 300 mile a day speedsters, it won't necessarily mean we can avoid the bad bits, but it will give you a good idea of what you will be getting, and enable you to prepare for it. And in any case, the sort of weather those speedsters are chasing is the sort of stuff we try to avoid.


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