A winning strategyMar 3, 2010
You have a voyaging yacht and are about to invest in some pricey long-distance communications equipment, or you have already bought the gear and find that it does not live up to the advertised claims, even after you've had the equipment professionally installed.
One could ask if there really is that much bad equipment on yachts. I suspect that is not the case. Rather, there's likely a combination of issues in play.
For example, were operators unfamiliar with recently installed gear? Was radio propagation &mdash the life blood of SSB shortwave communication &mdash poor during the times when users were unable to make solid connections? In the case of bad satellite communications, was an inadequate satellite footprint or other anomaly the culprit? Most important were a number of operators not employing the best operational techniques for the propagation conditions they experienced?
Don't forget that Guglielmo Marconi, who is widely considered the father of radio and its many descendants, first bridged the Atlantic with antique gear in 1901. Surely, in 2010 with your modern gear, you should be able to communicate. As a first step, particularly if you are a radio novice, study your radio manual. If you do not yet own a radio, but know the one you want to purchase, download the manual from the manufacturer's Web site. More important, you should understand a bigger picture which not only involves your radio, but other components necessary for successful communications. Failure to understand the bigger picture and work with it is often the root cause of communication failures. Successful communication strategy (C) is a function of adequate radio propagation (P), smart operator techniques (O), and proper installation of good equipment (E). A simple mnemonic device to remember the winning strategy for successful communications is: C = P+O+E.
Propagation is a term that describes how radio signals are affected when transmitted from point A to point B on the earth generally by refraction or reflection off the ionosphere. The ionosphere is an ionized layer above Earth at the edge of space. Some radio signals at certain wavelengths or frequencies permeate the ionosphere while signals at other frequencies can be otherwise absorbed, refracted, or in some cases reflected. In these latter examples, great communication distances can be achieved without benefit of artificial satellites. This is what makes long distance shortwave communication possible.
However, this comes with drawbacks. The ionosphere is in constant change just like the weather on Earth is always in a constant state of change. This means radio signal strengths and communication distances can be boosted or diminished because of propagation variation. So, good or bad radio propagation refers to its affect on communications. Like weather on Earth, radio propagation status can be forecasted. Also, radio propagation forecasting, like Earth-weather forecasting, is an inexact science. It can be pretty accurate however when we talk about forecast trends over a long period.
The outer limit of the ionosphere is at the edge of space. This edge reportedly can vary between 400 miles altitude above Earth at night and up to 600 miles during the day. As the layer drops in altitude, the distance that high-frequency (HF) signals are refracted decreases so that two stations hundreds or thousands of miles apart may not be able to communicate on a specific frequency. Stations operating on the lowest HF may experience greater ranges at night, but seldom the globe girdling distances of the higher frequencies during the day. This is why you may hear an AM-band station, located hundreds of miles away, at night while the same one is inaudible during the day. This daily variation is largely affected by the strength of extreme radiation from the sun. At the same time the strength of this radiation follows an 11-year cycle popularly known as the sunspot cycle.
During the maximum of the 11-year cycle, the number of sunspots increases. These are regions on the sun's surface that are characterized by intense magnetic activity that radiate to the ionosphere. Scientists measure the intensity of these solar transmissions by a scale called the solar flux. A higher flux number means more radiation bombarding the ionosphere layer. Ionosphere density is improved. Also, when this occurs the ionospheric layer lifts. This improves the ability for HF stations, particularly on the higher frequencies, to communicate greater distances, if not globally. Signal strengths even over thousands of miles are often outstanding. For example, during the last sunspot cycle maximum, I was able to communicate with HF ham radio stations on seven continents during the same day. Radio contact with offshore cruisers thousands of miles away was also possible.
Unfortunately, during the sunspot cycle minimum, global communications becomes increasingly difficult and shorter circuits of hundreds of miles to 1,500 miles become more problematic. We are now experiencing cycle 24, which is in the solar minimum.
As a first hand observer I have noted 24- to 48-hour periods of improved long distance communications followed by days of poor propagation and weak signals. The falling ionosphere has apparently made Cycle 24 minimum propagation conditions worse than expected. Yet, all is not lost &mdash the prospect of long-term improvement was slated to begin in 2009, with further improvements through 2012.
Smart operator techniques
As you have probably figured out, HF marine operators will have to work with the current radio propagation situation just as with the latest weather when planning to cruise. After all, we cannot change the propagation just as we cannot change the weather.
HF communication is based on science, but its success ultimately depends on the artful skill of the radio operator. In other words, you are in charge of properly "driving the radio."
While an article of this length cannot cover every possible technique for operating a radio, it does focus on some important tips which should allow you to communicate successfully. In this regard it is important to know how to operate the radio now rather than trying to figure it out en route to your favorite cruising ground. That approach is a recipe for failure.
Operators can practice before going offshore by participating in nets and talking to other marine operators by means of prearranged schedules. General monitoring of important marine channels carrying weather information is also a good idea. Learn to record broadcasts so you can do it offshore. A recorded weather forecast can later be referenced for details you might have missed. Obtain some earphones as they will be handy underway when trying to operate as other crewmembers are sleeping below. The earphones also cut out extraneous noise while communicating on your radio.
To begin with, HF marine operators should also pay attention to radio propagation forecasts made by observatories around the world like the Australian Space Weather Agency. Also, in the U.S. the National Institute of Standards and Technology (NIST) provides such information. NIST transmits propagation reports on WWV (2.5, 5, 10, 15, 20 MHz) from Fort Collins, Col.
Part of an operators propagation watch should also involve listening to various portions of the HF marine spectrum to see which frequencies seem to be supporting communications at the time of the day an operator intends on operating. Another good aid is the strength of the WWV signal at your location. For example, if WWV is strongest at 10 MHz, fairly strong at 15 MHz and inaudible at 2.5, 5, and 20 MHz, then the 8 to 13 MHz bands will probably support some longer distance communication. The 2 to 6 MHz bands might be better for closer-in communications.
In essence, you should pick the correct frequency band in the HF spectrum to optimize chances of a successful radio contact. Signals still may be weak, subject to fading, and have some noise. Alternatively, they maybe nice and strong. The point is that the frequency you select should give you the best possible signal for the prevailing radio propagation. Keep your expectations realistic based on the conditions.
Remember that individual day band conditions can be better or worse because of changing radio propagation which is affected by the current solar cycle minimum conditions, low sunspot number, low solar flux, solar storms and severe, localized lightning storms.
Seasonal variations can also affect propagation. For example, winter, early spring and late fall generally tend to favor better propagation and longer distances on lower frequencies (2 to 8 MHz) in the late afternoon through night. However, late spring, summer, and early fall tend to favor better propagation and global communication distances on the higher frequencies (12 to 22 MHz) during the daylight and sometimes in the evening hours.
Also, keep in mind the minimum and maximum distance rules for the various frequencies you want to operate. The minimum distance rule of thumb is MHz x 100 = minimum distance (e.g., 4 MHz x 100 = 400 miles). The maximum distance rule of thumb is the minimum distance for a specific frequency in MHz x 2 = maximum distance (e.g., the 4 MHz minimum distance is 400 miles x 2 = 800 miles).
Good operating techniques, to include the use of phonetics, prearranged schedules with shore stations on multiple choices of frequency, and the use of scheduled marine nets on different frequency bands of the HF marine spectrum are highly recommended. This approach allows you to best use the propagation conditions that are available. Leveraging the propagation situation to your advantage is key, just as leveraging the weather and sea conditions when sailing.
Adopting this approach means that the HF operator should program the radio with various frequencies that could be used offshore. While there are probably 1,000 possibilities, most radios come with many frequencies already programmed to specific channels. In the case of my Icom M802 HF SSB radio, useful frequencies were pre-programmed into channels 1 to 124. For example, USCG emergency frequencies, voice weather broadcast frequencies, some ship-to-ship channels, and a few important nets were already available for use. Thirty-six other channels were left for me to program with frequencies important to my operations. Besides programming some nets and other two-way frequencies, I also included some frequencies of popular AM broadcast stations, and some shortwave broadcast outlets such as VOA, BBC, and Radio España (great for helping maintain my Spanish language fluency).
You should maintain an available list of what frequency is on each channel. For example, WWV 10 MHz might be listed against channel 125. When offshore, the list will provide you an instant reference to contact a specific station, or listen on a certain frequency. I keep this list in a loose-leaf binder along with the radio manual and other references such as net information and communication schedules.
For example, there are many useful HF marine nets focusing on the Atlantic, Caribbean, Pacific, etc. Do some research on the Web to identify those that would best meet your needs in a particular cruising region of the world.
If you have an amateur radio ham license you can also take advantage of the many ham-only nets that are available for passing messages or updating you on the weather. Powerful ham radio shore stations with large directional antennas can listen for you, thereby improving the chances of you being heard on land.
The use of prearranged yacht flotilla frequencies and times to operate are important when traveling in a small group, rally or race. All HF marine SSB voice communications are on upper sideband (USB) and in most cases would be simplex (all stations send and receive on the same frequency).
Another smart operational technique is to know how to use a commercial coastal radio station as part of your total offshore communications plan. They are an excellent resource for getting weather information, making phone patches to friends and family ashore, passing messages ashore or to other vessels, conducting commercial business, and asking for signal reports. The last remaining HF commercial coastal stations in the U.S are WLO and KLB. The former handles traffic primarily from the Atlantic and Caribbean while KLB focuses on the Pacific region. For a nominal annual fee you can register your station afloat by mail while providing them with credit card information. In this way you can later call them from offshore and they can then make phone calls for you connecting your yacht to the telephone system (phone patches). Calls are securely billed to your credit card without you broadcasting this information over the air.
These coastal stations run very high power transmitters with directional antennas. They operate 24/7 on different marine bands listening and transmitting on USB in duplex mode (stations receive on one frequency and transmit on another). The probability of having successful communication is very good. For example, I have had excellent luck with being heard from the east coast whenever I called station WLO that is located in Mobile, Ala. These stations are also available, at no charge, for an occasional radio signal report to see if your set is working. Additional information about these commercial resources is available at www.shipcom.com.
Satellite, data, and VHF communications
Knowing the various means available to get weather information via voice or fax when offshore is a very important part of being a smart HF operator. As noted previously, offshore communicators can use various marine and ham nets to obtain voice weather reports. Also, a simple laptop computer properly loaded with fax software and connected to an audio output jack of an SSB radio can become a ready platform for giving voyagers the latest NOAA weather charts. The Coast Guard routinely transmits both voice and fax weather information on various marine HF frequencies. The easily copied signals from a number of different Coast Guard transmitters cover the Atlantic, Caribbean, Gulf, and Pacific. See the Web for the latest schedules/frequencies: www.nws.noaa.gov/om/marine/hfvoice.htm ; http://weather.noaa.gov/pub/fax/rfaxatl.txt.
Operators may also want to add to their sources of weather information by installing a satellite Sirius XM weather receiver. A chartplotter or a laptop can serve as the data output screen. A monthly subscription is required only for the months of the season you plan to be sailing. This is another system to help you build a truly robust electronic suite aboard. These systems provide substantial, but not total offshore coverage.
Knowing how you can exploit the e-mail capability of an SSB radio provides another means to communicate to other yachts or the shore. E-mail adds redundancy to a total offshore communication system. NOAA weather GRIB files containing raw weather data can be transferred via a pactor modem and laptop connected to an SSB radio. Although slow by high-speed Internet standards, this set-up offers a relatively high degree of reliability for e-mail. This can be done on HF marine frequencies using an annual fee service that is supported by SailMail software. A free service via ham radio using Winlink is also available. You will need a Federal Communcations Commission general class ham license in order to use the ham radio system. Additional information on how to get a license, with no Morse code test required, is available from the American Radio Relay League at www.arrl.org. And, the ARRL and various commercial vendors such as Dockside Radio have more information on setting up e-mail on an HF SSB radio.
When offshore, the yacht AIS or radar (if so equipped) can be used to identify other vessels in the area which may then be contacted by HF or DSC VHF radio. This technique could be very important to summon assistance in an emergency, or to obtain weather or navigational information. HF operators should be prepared to take advantage of local communication resources when needed.
Besides AIS and radar, HF operators should be knowledgeable of satellite phones like Iridium and Globalstar. These systems provide global coverage in the case of Iridium and more regional coverage in the case of Globalstar. A one-way satellite transponder device called SPOT, also available from Globalstar, is capable of transmitting a yacht's position, status of the crew, or an emergency message.
Touchtone dialing on the Iridium and Globalstar phones to numbers worldwide is potentially possible. In a pinch, the ability to instantly dial a boat chandlery to order a critical part, to transact important business, to download weather GRIB files, or to connect with the Internet using an accessory data package wired to a laptop computer is nice to have. Some problems that may occur with these systems can be caused by poor installation, operator error, failure to "see" the satellite, or the very occasional equipment failure. Operational costs, particularly for the phones, aren't cheap compared to HF SSB.
This said, HF SSB radios plus SPOT and/or a sat phone (with or without a data package to a laptop), and a Sirius XM satellite weather receiver provide plenty of communication redundancy and weather data. The advantages of each system can be leveraged to assure communication and the receipt of timely weather information.
An understanding of radio propagation and properly installed quality equipment is the key to successful offshore communication.
Curtis Morris is a retired USAF colonel with consulting experience in government, private, and academic sectors. He has been a licensed ham radio operator (K7KNM) since 1959. He also holds a commercial marine (WDD5867) operator license.