Why Consider On Board Single
Sideband Radio (SSB)
I have made a promise to the various family
members and friends to remain in touch via eMail - even when I'm out sailing.
Now my problem is how to keep this promise without breaking the bank on
communication equipment and services. For the near future, I believe that
Amateur SSB radio communication is the best way to go. With SSB, I can
communicate over a range of several thousand miles and this will clearly meet my
needs.
SSB radio for eMail requires several major
items of equipment - and all of them need to be as small as possible.
1) A Transceiver capable of SSB operation on
the frequencies of interest and digital transmission modes
2) An Antenna
3) An Antenna Tuner matched to the transceiver model
4) A Radio Modem
5) A Laptop Computer
The guiding principle for equipment selection
must include low cost, small size and low power consumption.
As a guess, a new commercial marine SSB
installation with the hardware required for eMail (not including the laptop
computer) will cost around $3,500 plus installation ($1,000 to $1,500
generally). The commercial service contract will also have an operating
cost of about $450 or more per year depending on how much you use the eMail.
By getting an Amateur Radio License, I hope to get this down to about $1,500 or
less going the route of used amateur radio equipment - an added benefit is that
there would be no significant operating costs and I will do my own installation
which will save significantly.
Commercial Marine SSB
In 1999, AT&T closed their Public Coast Radio Stations since they claimed
that their continued operation was too costly and that other means of offshore communication
such as satellite were available. For the commercial marine segment (and
private individuals with Fat Wallets), this is clearly true. However, for
the little guy, SSB is still a very good option.
As of now, there are still several smaller commercial Public Coast Stations
in operation - the majority of which provide only SSB
eMail service. If the sailor needs to send business related eMail,
then this type of SSB is the only option since Amateur Radio is forbidden to
transmit business related messages. Also, if obtaining an amateur Radio
General Class License is not possible, then this is the only way to go.
The advantage to the commercial option is that you pay for a service and have
a choice of providers (even if the list is small). Also, the Marine
Operator's Permit and Station License that is required do not require technical
tests to be passed. Since the operator permits are universally recognized,
no special requirements exist when crossing international borders.
The main disadvantage of the commercial route is the limited selection and
higher cost of the FCC Type Accepted radios that are required to operate in the
Marine frequencies. Even in the used market, these radios can cost
two times the amount of an equivalent Amateur radio. In addition, there
are some significant fees associated with Commercial eMail services - both
annual contracts (about $30 to$40 per month with a one year minimum contract)
and additional usage based fees that can range up to $1.00 per message unit.
In this case a message unit is defined the smaller of one message or a block of
1000 characters (including control characters). This means that a two page
letter via eMail will cost $2. Even with limited uage, this can add up to
a fair chunk of change.
Amateur Radio SSB
In order to participate in Amateur Radio, a valid FCC license is required.
On December 30, 1999 the FCC announced a major restructuring of the License
requirements. Under the new rules scheduled for implementation on
April 15, 2000, a General Class License will still be required for access to the
frequencies in common use for long distance eMail. Under the new rules,
this License will require passing two written exams on rules, theory, practice,
and safety of radio operation. In addition, knowledge of Morse code is
required and the operator must be able to send and receive at a speed of 5 words
per minute (25 characters per minute). Passing the written tests should
require some study with a few good books since all of the possible questions on
the test will be published for anyone to review - the Morse Code test will
require more concentrated study with one of the many Morse Code Tutor programs
available on computer.
Amateur radio is composed of a universe of dedicated hobbyists - many of whom
also are sailors or pursue other mobile recreational activities. In
response, a network of Amateur stations have been established to provide
gateways between the world of Radio and Internet based eMail. These are not
commercial activities and the stations will come and go as time and the
operator's interests dictate. However, there seems to be enough interest
in this activity to assure some degree of connectivity for the near future.
From an equipment standpoint, there are several manufacturers and a steady
supply of relatively modern and less expensive used equipment on the market.
However, Amateur Radio is licensed by each country and as an amateur operator
crosses international borders, a new temporary operating permit application will
be required in each country with a generally small fee being paid. In the
Bahamas for example, the fee is $6.00 - the permit is usually issued within a
week or two and is valid for a period of one year. In Canada, no
application is required but in Mexico, an application is required and processing
may take more than one month while the permit is only valid for six months in
total (including procesing time). In other words, plan in advance!
My plan is to be in line as soon as the new rules go into effect and pass the
examinations required to get my General Class License. In the mean time, I
will continue to scout the auction sites and Ham swap meets for the equipment I
require. Due to the transition plan between the old and new rules, I
may take some of the examinations under the old rules in order to get a jump on
the requirements.
Commercial Marine Radio Equipment
In order to use a SSB radio for Marine use, it must be type accepted by the
FCC. As of now, this limits the market to companies such as Icom,
SGC, and SEA. There are other high end providers but their equipment
is out of sight for all but the large commercial vessels. Some of these
manufacturers also provide dual purpose units that are capable of both Marine
and Amateur service. In this capacity, they are really Marine radios that
can transmit out of their assigned bands into the amateur frequencies - they are
no where near as flexible in their operation as most Amateur Radio operators
would like to see.
From what I have seen, the most desirable Marine radio would be the
Icom M700-PRO model or the similar ICOM 710. These models are
available from
West Marine and most other marine suppliers at a cost of about $1,100
to $1,600.
A matching antenna tuner (Icom AT130 ) is also required and sells for
about $500
Amateur Radio Equipment
There are a significant number of companies producing Amateur Radio equipment
for the 2 million or so amateur Radio Operators worldwide. With a
relatively large market, there is also a significant amount of used equipment
available so this might allow cost cutting. Since a driving force behind
my requirements is to have eMail on my sailboat, I will need to concentrate on
more modern equipment designed for low power consumption and digital
transmission capability. One additional requirement is that the receiver
be general coverage so that receipt of SSB Weather Charts is possible.
For those interested in listening to the international broadcast frequencies,
the older Amateur radio tranceivers supported AM reception which is sometimes
easier to use than trying to tune an AM signal with an SSB receiver.
My first amateur radio consisted of an ICOM 735 purchased used. This
worked well but was physically large and consumed more power than I would have
liked to use. At it's minimum settings, the unit transmitted at 10 watts
and I found that this was more than I needed. I then went looking at
alternatives and now, my station consists of an Elecraft K2
transceiver with the internal SSB module and antenna tuner options
installed.
The Elecraft K2 was selected due to it's low power consumption
and high quality receiver functions. This radio is only available in kit
form from the manufacturer but the process of building the radio is well
documented. It took me about two and one half weeks to complete - and that
was while living aboard the boat. Conventional wisdom says that you need
100 watts of power to communicate via SSB - NOT TRUE. I have never had a
problem exchanging email with land based stations using only the 5 watts that
the K2 supports in digital modes. In fact, I have been successful with
less than 2 watts over a range in excess of 1,000 miles.
Figure 1: Pactor IIe Modem and Elecraft K2 Transceiver
Radio Modem
With respect to the Radio Modem, the top of the line is the Pactor II from
SCS. At a price of about $1,000, this would not be a realistic
selection for my purposes. Even the Pactor IIe economy model sells for
almost $650 and is too new to be found on the used market. Since money is
tight, I should start with older technology such as the Kantronics KAM Plus or
AEA PK232. With upgrades available from the manufacturer, these units
support the Pactor I but not Pactor II protocol. Ebay seems to offer a
number of these at any point in time but the price of a used unit with the
additional costs of upgrading to the current version firmware will bring the
total to $250 or more. Also, even with the upgrade, these units are
still only capable of Pactor I operation and not the much more efficient Pactor
II. Furthermore, the software of choice for eMail over amateur radio does
not support all brands of modem so this will impose additional limitations.
It seems to me that efficiency is the killer in this equation. I really
don't want to spend the money for the Pactor IIe unit, but since it operates
about 5 times faster than any modem using Pactor I, I really don't have much
choice. The electricity supply on a small boat operating off a solar panel
system is the deciding factor, if I can cut down on electricity consumption with
a better modem, this is the best solution despite the higher initial outlay from
my coin collection..
I will not minimize the complexity of this operation. Getting an
Amateur Radio, a Radio Modem, and a laptop computer to operate together is not
"Plug and Play" - it is not an easy task - and then it must
still be able to communicate with a similar setup several hundreds of miles
away. This will take time and effort to establish the connectivity. I
followed the hardware installation recommendations given on the Airmail
2000 software site - including the use of clip on ferrite chokes on all
interconnecting lines (radio, radio modem, and laptop computer)
Antenna Considerations
A sailor can have the most expensive SSB radio, the best Radio Modem, and the
best Laptop computer to connect them for digital communication and still not be
able to communicate across the anchorage or out of shouting range if the antenna
system is poorly designed. I have no intention of going into antenna
theory here - I just want to describe the options I have considered and then
describe my starting point.
Conventional wisdom says that a good SSB antenna on a sailboat is VERY
difficult and EXPENSIVE to install. The experts will ramble on at great length
about the requirements for a counterpoise (ground plane), the cost of backstay
insulators, special weatherproof automatic antenna tuners, and special cables to
join the various pieces. The experts are absolutely correct - but only if you
want access to SSB transmission at any and all frequencies both at anchor and
while under way. However, if you only want to use SSB transmission
every few days while at anchor - is it still difficult and expensive - NO!!!
The Expert's Antenna Choice for a Sailboat
There are several commonly used antenna configurations for a sailboat - most
users install an insulated backstay for their antenna with some others
installing a vertical whip (23 feet tall minimum). In either case, the
major factor that determines good long distance operation will be the
installation of a very high quality ground plane (also called a counterpoise)
for the antenna. These antenna types also require a sophisticated (and
very expensive) antenna tuner to operate correctly.
For either of the above antennas to operate on the many different frequencies
of the Marine and Amateur services, the antenna must be at least 23 feet long
and the antenna tuner must be connected to a ground system composed of copper
foil radials that are as long as possible and have as much surface area as
possible. Some experts suggest that a minimum of 100 square feet of copper
foil is necessary for good operation with a backstay or vertical whip. One
thing is essential and that is to keep the antenna tuner as close to the antenna
and the ground plane connections as possible (no more than 3 feet).
If copper foil ground planes are to be constructed, the recommendation is to
make each of them at least 20 feet long and 3 inches in width (5 sq ft at a cost
of about $25) - as many of these radials as possible should be installed.
Another approach is to use wire mesh screen (copper if possible) as a
ground plane.
This arrangement is the most flexible and will allow operation under all
conditions (as long as your rigging stays intact). The insulated backstay
is expensive ($200 or more for the two insulators) and the insulators are a weak
point in the rigging design. Experts recommend replacing the insulators more
frequently than any other part of your rigging. The antenna tuner
(about $500) will match your backstay to all frequencies without damage to your
transmitter - but the efficiency of transmission may be less than 10% (150 watts
from the transmitter but only 15 watts out via the antenna with the rest of the
energy showing up as heat in the tuner and ground losses). Modern antenna
tuners will match a transmitter to a length of string soaked in salt water - but
this does not mean you will be efficient at transmitting.
The total installation may well take several man days and require access to
every nook and cranny of the boat - a REAL mess!! Also, on a Flicka, the
length of the backstay and the length for installing counterpoise radials is
minimal at best.
My Non-Expert Antenna Choice for a Sailboat
My use for SSB radio is as a means of communication with friends and family -
digital transmission for eMail will be the major mode of operation. This means that my needs are very limited and I
will only use the system at anchor and not while underway. As a coastal
sailor, a good VHF system is much better for emergency and routine marine
communication. At anchor, I can raise a temporary shortwave antenna into
the rigging, get my eMail, and then put the system away.
The design of high quality temporary antennas of this type are well
understood and can they can be produced inexpensively. Amateur radio
operators have been using them for years on Field Day and other emergency
preparedness tests. Most automated communications is limited to a narrow
range of communication frequencies with world wide coverage potential (30 and 20
meter wavelength). For the frequencies I need access to, an efficient 1/2
wave length dipole antenna will range from 46 feet long down to 33 feet long (30
and 20 meter wave lengths) as end to end dimensions. Dipole antenna's
consist of nothing more than two sections of stranded copper wire (insulated AWG
14 will do) with an insulator in the middle of the two sections and on both ends
- the whole thing looking like a clothes line. The connection to the
transmitter is made at the center (called the feed point) - generally with high
quality coaxial cable. Physically, this antenna can be arranged in two ways
- as an inverted "V" with the center raised to the top of the mast and
the ends suspended by their insulators fore and aft, or as a "sloper"
with one end at the mast head and the other end suspended from the pushpit.
The single largest advantage of this arrangement is that NO COUNTERPOISE
IS REQUIRED!!
There is no free lunch, while efficient, this setup means that you should
construct one antenna dedicated for each band of operation. Also, the
antenna is somewhat directional with very little radiation off the ends of the
antenna (fore and aft). If you sailboat is swinging significantly at
anchor, a contact might be difficult to maintain unless you use two anchors.
Using the Dipole antenna approach is especially attractive to a salt water
sailor since the electrical properties of salt water make it an ideal reflective
ground for radio frequencies. This is why long distance transmission of
radio waves over salt water has long been known to be very efficient.
Additionally, that lonely anchorage also is missing much of the the man made
electrical interference that radio operators need to spend so much effort at overcoming.
There is an alternative arrangement of the inverted V dipole antenna that is
even simpler to construct for use on a small sailboat. This is the Resonant
Feed-Line Dipole antenna and details on it's design are available via the
internet. I'll start with this system since it is so easy to set up.
Another choice for antennas is the Pro-Am Valour (Ham Stick) series of
antennas. At the frequencies I operate for email, these antennas are
efficient and easy to set up. The mount is attached to the pushpit and the
toe rail of the boat is ties electrically to the pushpit to act as a radial
counterpoise. Additionally, a section of ten feet of tinned braided copper
cable is run to the saltwater whenever this antenna is in use. Figure 2: Hamstick Antenna mounted to the stern rail
SSB Weather FAX Service
Once a good quality Single Sideband receiver (Unfortunately, the Elecraft K2
only covers the Ham bands and receipt of weather FAX is not possible with this
radio.) and computer are on board, a
logical extension is to use the equipment to receive the latest weather
information. The Coast Guard has a broadcast schedule of weather products
for mariners that includes a number of charts as well as text and voice transmissions
of weather reports. A schedule of transmission
frequencies and timesbelow the listed frequencies using UPPER
sideband. Remember that atmospheric conditions, distance from the
transmitter, and time of day will determine which of the listed
frequencies you will be able to receive from your current location. Don't
expect these weather maps to be in extreme detail like your local TV news - they
are general in nature but will give you a good idea of the conditions you are
likely to encounter when you are out of range of the usual sources of broadcast
weather data. is available on the web. Broadcasts that
cover the area of interest for me (Florida with points south and east) are
issued from Belle Chase LA. Currently (Spring 2000), they use frequencies
of 4317.9, 8503.9, and 12789.9 with the schedule of transmissions starting at
00:00, 06:00, 12:00, and 18:00 UTC - each scheduled transmission block lasts
just over 2 hours. A complete broadcast schedule is also issued at 06:30
and 18:30 UTC in HF-Radio FAX format. To receive the broadcast, tune
1.9 KHz
Knowing when a Weather FAX chart will be transmitted won't help if you can't
decode the chart to display on your laptop computer. For occasional use, I
suggest JVComm 32 (In January 2000,
the most current version was 1.0 and the registration fee was $68). This
shareware program will use the Soundblaster compatible hardware on your Windows
95 or higher laptop computer to decode the transmission and display the received
chart on the computer screen. Under some conditions, a direct connection
between the computer and radio is not even necessary since the decode process
can use the computer's microphone input if the computer and receiver are close
together. Be sure to test the software using the demo download on your
computer system before actually purchasing it. The current version
software (Version 1.0) requires a download of about 3.5 MB. If you need
access to weather maps more frequently, the dedicated HF radio modems are much
better and more reliable. JVComm32 supports the Pactor IIe modem
directly so there is no need for the sound card.
The Coast Guard stations also broadcast weather information in English (using
a computer generated voice that is sometimes difficult to understand) on the
same frequencies. There are other weather broadcast formats available in
text form (a radio modem is required) - information is on the links page.
While we are on the subject of Time - do not neglect to set your watch using the
WWV broadcast on a frequency of 2.5, 5.0, 10, 15, or 20 MHz. This is
also a nice way to check the calibration of your receiver's frequency display.
Sailboat SSB Directionality
Effects
The Hamstick antenna described above is normally expected to radiate it's
signal uniformly in all directions. The caveat is that this radiation
pattern is expected when the antenna is mounted in the clear and away from any
other metal objects. Unfortunately, a sailboat is far from a clear
location for an antenna mount.
Computer antenna modeling shows that the 25 foot mast on a Flicka is the
perfect height to act as a passive antenna element on frequencies of 14 MHz (20
meters) and above. Depending on the frequency in use, the mast will
function as either a director or a reflector. This means that the majority
of the radio signal will be beamed either off the bow or off the stern - again
the direction will be frequency dependant.
Since I use frequencies in the 30 meter band (around 10.125 MHz) most often,
I do not experience this directionality effect. However, the computer
models clearly show that I should avoid higher frequencies. |