Editor's Note: Most of the
inline images were not included in this document to speed up
internet load times. Follow the links to see the approriate
drawings.] So you're sailing to Hawaii
AND you want to be able to call home while on the way. But
most of all you want to be heard if you call for help from
the middle of nowhere. Communications on the open
ocean has always presented a problem. The distances are vast
and the transmitting platform is small, unstable and
designed for a purpose other than being a radio station. If
we exclude satellite technology, choices for the average
mariner to communicate several thousand miles are about the
same as they were 50 years ago. Marine Single Side Band
(SSB) radio, also referred to as HF radio, is an "old
standby" of voyaging vessels both small and large. It is
called HF, or High Frequency, because of the frequency range
used, 3 to 30 megahertz (Mhz). Medium Frequency (MF) is
below at .3 to 3 Mhz and Very High Frequency (VHF) is above
at 30 to 300 Mhz. Commercially available
marine SSB radios are pretty sophisticated machines. They
range in price from $1500 to $10,000+ with many different
configurations available. As with most electronics, from car
stereos to computers, the price of equipment goes up with
features and power capabilities. Output power, expressed in
watts, of common marine SSB equipment is 150 to 400 watts
with some shipboard equipment in the 1000+ watts range.
Anything over a 150 watt radio is a big machine and for all
but a few yachts too expensive and unnecessary. Transmitting over the
airwaves with a SSB radio is always free as long as
youre not connected to a commercial service. It is for
this reason that SSB is most often used for vessel to vessel
communications when the 30 to 40 mile range of a VHF
transceiver is insufficient to cover the distance between
the two vessels. You cant beat it for things like "Hey
Jim, how's the weather over there?" Current and upcoming
satellite technology is better suited than SSB for making a
connection to a landline phone, but the per minute air time
charges are real, and so are the monthly service
subscription fees (whether you use the phone or not). The
average Jim will probably tire of you calling on the sat
phone and costing both of you $$$! With the help of your local
marine electronics specialist you have selected a radio
system that fits your needs and budget. You will be loaded
up with a SSB radio, an automatic antenna tuner, copper
strap, wire of different types and connectors. If you opt to
do the installation yourself, the radio system will occupy
at least one weekend for you and a best friend to install
properly. Don't underestimate the difficulty of properly
installing a SSB radio. It is not as technically difficult
as it is laborious but as with anything on a boat, attention
to the details will make the difference in
performance. For this discussion we will
assume we are talking about an average 40' fiberglass or
wood sloop with an inboard engine and an external keel with
keel bolts. Steel and alloy boats will not have the same
considerations for a ground system and ketch / yawl rigs
have unique antenna problems that need to be addressed
individually. A boat is a difficult radio
platform and as most experienced boat owners know, a boat is
always a compromise. With respect to a SSB radio on a boat
the problem lies in that there is no earth ground plane or
"counterpoise" for the antenna system, so one must be built.
In a land based installation ground is usually easy.
Pounding a 6' copper stake into the earth and / or grabbing
onto the copper plumbing in a house can provide a sufficient
ground plane. A good ground is vital, it is half of the
antenna system and is often referred to as the springboard
the signal uses to jump off the boat into the atmosphere. To
better understand "ground" you need to know the three
different ground systems that can exist on a boat. One is
your DC ground which is the negative post of the battery(s)
that all of your DC powered items are ultimately common
with. The second is the bonding system which is intended to
tie all of the metal items in the boat together that may be
susceptible to electrolysis (galvanic corrosion). The third
is your RF (radio frequency) ground for a SSB radio. An
astute reader will note that all three ground systems are
common to at least one point, the engine. In the case of RF
ground, the other ground systems are inconsequential and of
no benefit to the RF system. No
Pain, No Gain. Think Metal Surface Area. The RF ground
installation is different for every boat but the basics are
the same. You want to attach all big metal items on the boat
together with copper strap and end up with a minimum of 100
square feet of metal surface area. Starting with the
Automatic Antenna Tuner, the tuner should be mounted close
to the feed point for the antenna which means it is usually
mounted aft. From the tuner, copper strap will run forward
and attach to the engine, any (and hopefully all) metal
tanks and a keel bolt (any one will do). Getting the copper
to metal toerails and the stern pushpit along with the
lifelines can be of tremendous benefit. When incorporating
the pushpit and lifelines, extra care must be taken with the
route of the antenna feed wire. See
Figure 2. Transceiver and automatic tuner
connection The copper strap is
commercially available from marine electronics shops and
ranges from 2" to 4" wide and in thickness from .001" to
.013". Two inch wide .001" (about as thick as an extra heavy
aluminum foil) is easy to install around the boat but there
is a trade-off when using the thin stuff. The issue is
surface area and longevity. At HF frequencies electrical
energy is no longer running through the copper conductor as
it does at DC voltages, but rather it is traveling on the
surface. Copper strap is used instead of wire because the
strap has much more surface area and offers less impedance
(resistance at frequency) to the RF energy. Armed with this
knowledge, we know that 4" strap is going to be more
effective than 2" and that the wider material should be used
whenever possible (some Whitbread boats are using 6+ inch
wide copper) . However its an imperfect world
especially when working on boats: sometimes 4" strap just
will not go from point A to B. Four inch material folded in
half is one solution and sometimes the ultra thin .001" x 2"
copper is the only way to go but make every effort to use
bigger material. The life expectancy of .001 mil copper is
shorter than thicker material because it rots from corrosion
in the salt air much faster. Of course life of the copper is
only an issue if it is a permanent installation . In the
really perfect world, the boat builder would have laid
copper screen and foil in the lay-up of the fiberglass
during construction completely encapsulating the material,
exiting copper tabs in the appropriate locations to attach
to the tuner and metal objects. Many boat builders now offer
a SSB ground plane as an option for new construction
jobs. When attaching the copper to
tanks, keel and engine try to do so in a way that achieves
good metal to metal surface area contact. In the case of
tanks, running to an inspection plate and attaching to a
couple of the bolts with large washers works well or going
to a fitting on the tank and attaching the copper to it with
a hose clamp also works. The latter looks crude but is
effective. Some tanks have cleats or clamps holding them in
place that can be loosened and the copper sandwiched in
between. At the engine, choose a bolt to sandwich the copper
to the block . You may want to ask your mechanic which bolt
he would suggest to use. Why
an automatic tuner? The antenna tuner is an essential
component of the installation and an automatic tuner is
required for most marine installations. The tuners
function is to match the impedance of the antenna system
(the combination of backstay or whip antenna and the ground
plane) to the 50 ohm impedance of the final transmitter
stage at the back of the radio. This is no small task as the
impedance of the antenna system can change from a few to
hundreds of ohms depending on the frequency transmitted on.
So you say big deal? Only when the impedance is matched does
the maximum transfer of power take place between the radio
and the antenna system. Without a proper match all of the
radios energy doesnt make it past the tuner and in
turn off the boat. Energy is reflected back towards the
radio producing what is called a Standing Wave (SWR), a
ratio between forward and reflected power before it goes
through the tuner. An imperfect match between the radio and
antenna is one of the reasons lights on your electrical
panel will glow and volt meters will bounce when
transmitting on a SSB. Out of the tuner comes the
actual radiating high voltage. Naturally you want to radiate
out of the boat, so the shorter the run from the output of
the tuner to your insulated backstay or whip the better. A
manual tuner will also do the job but it needs to be mounted
by the radio where it can be manipulated when the desired
working frequency is changed. The problem with a manual
tuner being by the radio is that the radio is usually a long
way from the antenna element. The long run from the tuner
output to the antenna will not make an efficient antenna
system and will result in a lot of RF energy being absorbed
by the boat. A word of caution about
automatic antenna tuners. Automatic tuners available today
from major radio manufacturers use micro processors and
refined internal software to match the antenna to the
transmitter. They are very good at their job, which can
create a problem: auto tuners can tune what is effectively a
inadequate antenna system. It has been said by some people
that all you need for a ground plane is run a wire from your
tuner to a metal thruhull and your system will operate. The
tuner may indeed tune, but a majority of the energy from
your radio is lost in the process and never escapes the
boat. The difference manifests itself in being able to talk
less than 1000 miles or the 6000+ miles you can achieve.
Heres the catch: for all practical purposes, a
technician cannot put a "tester" on your system and tell you
definitively how good your system is. A watt meter is a tool
technicians use that can be put in between a radio and the
tuner to give an indication of how well the tuner is
operating, but the "business end" of the tuner is the high
voltage terminal that hooks to the antenna element
(backstay, whip, etc.). An experienced radio technician with
the aid of a watt meter and knowledge of a good quality
ground installation as outlined previously can make a
educated call as to whether the system is working properly,
but the real proof is whether you can make 3000+ mile radio
contacts consistently. Apply the rules that have proven to
be effective: 100 Square feet of ground surface area
connected with copper foil and good metal to metal surface
area contact when making ground and antenna connections.
This is an ideal installation, and not every boat will allow
these goals to be met, but do your best. Primary
antennas. Your primary antenna will usually be an
insulated part of your rigging or a standing fiberglass whip
antenna in the back of the boat. These are both "longwire"
antennas, essentially a piece of wire held up in the air. An
antenna could also be as simple as a piece of 14 gauge wire
(back to that in a moment). The decision to insulate the
rigging or use a whip is usually driven by cost and
aesthetics as either will do a proper job. On a sailing
yacht, insulating the backstay is common as it makes for a
clean installation. The traditional guidelines for a
backstay are to have the bottom insulator 7' off the deck
and 3' down from the masthead. Insulated sections of
backstays longer than 35' are not necessary, however a
longer antenna may perform better. The RF output from the
tuner can be as high as 5000 volts at very low current and
grabbing the uninsulated part of an antenna while the radio
is being transmitted can cause a serious RF burn or could
even be lethal! Therefore the bottom insulator is usually
put 7' off the deck for safety reasons (Figure
3a). There are other styles of
fabricating a backstay antenna that offer better performance
(Figure
3b, Figure
3c). The bottom
insulator can be mounted at deck level or may be unnecessary
when the backstay chainplate terminates to the fiberglass or
wood construction of the back of the boat, which acts as an
insulator. With this type of installation, the backstay must
be insulated from possible contact with crew by putting an
insulating material over the backstay, turnbuckle, etc. The
best material is teflon tubing which has very good
insulating properties, however the tubing must be installed
on the backstay when the backstay is being fabricated by
your rigger. A distant second best material is white nylon
"snap on" shroud cover products available in chandleries.
Attention must be paid to items such as bonding system wires
that may be attached to the backstay chainplate(s). Also
note that a bottom insulator will have to be installed above
a hydraulic adjuster (3c). You may wish to hire your marine
electronics dealer to inspect your boat to make installation
recommendations. Insulating a backstay can be
expensive depending on what type of rigging you have, wire
rope, rod or as on some race boats spectra, kevlar or
technora. The cost of installing insulators sometimes leads
people to use a standing whip antenna instead. The whip is
tried and true and will do the job you require There are
whip antennas specifically made for SSB use and are 23' or
longer. Emergency
antennas. Take what we know about a primary SSB antenna
from above and an emergency antenna is pretty simple; a
piece of wire, 14 gauge or larger, 23' or longer from the
automatic antenna tuner up into the air. The automatic
antenna tuner will tune almost anything attached to it. The
$5 solution is 40' of 14 gauge wire with a ring terminal
sized for the output stud on your tuner, soldered on to one
end. The scenario is that you
loose the rig and along with it your insulated backstay or
transom mounted whip. "Lets tell everyone" being the third
or fourth thing on your mind, disconnect whats left of
the wire that went from the tuner to the now missing antenna
and attach your $5 emergency antenna, stringing it up in the
air by whatever means you have left on board (spinnaker
pole, boat hook, etc.). If 40' is more wire than you are
able to rig up, cut the new antenna as needed (no less than
20'). The antenna wire can be in an "inverted
V" as in up and over
a pole or mast stump, an "L"
and an "inverted
L" or really
whatever you can rig. Physically isolating the wire from the
support pole with a piece of line or a cushion on top of the
pole will improve performance. Its really that simple
because the high quality ground system that you installed at
the beginning of this article is still in tact and the power
of the computer inside your automatic tuner does the
rest. Wire,
connectors and techniques. The cost of high quality
materials are a drop in the bucket when compared to the cost
of the equipment youre installing. Marine specific
materials do cost more, but the performance benefits over
the long haul will be worth it. Tinned wire and connectors
for corrosion protection, wire of the proper size, sealing
tape to keep you connections dry and flat copper strap are
parts of a good installation. The basic techniques are
soldering connections, keep all connections bone dry and
good electrical connection surface area contact. While transmitting a SSB
radio on a 12 volt system, the peak current draw can be 25
amps for the average 150 watt radio. This amount of current
requires heavier gauge wire than most of the other equipment
on board. For the supply wire size you require, refer to the
"wire size to % voltage drop" table from the ABYC or the
same table printed in the Ancor Marine Grade Products
catalog. When terminating the supply wire, use the correct
size crimp ring terminal for the wire. Soldering the wire to
the terminal as well is highly recommended. Slip on some
marine type heatshrink tubing around the terminal and wire
for a professional finish that provides a strain relief and
water protection for the wire. There are usually two cables
from the radio to the tuner, one for RF and one to supply
operating voltage / control to the tuner. Follow your radio
manufacturers recommendations for the control cable and
consult your dealer. The RF connection from the radio to the
tuner should be made with RG-8U or RG-213 coax. This is the
big 1/2" stuff and will offer the least resistance to the RF
energy. The antenna connectors are UHF type PL-259. They are
tricky to make up the first couple of times and may require
a professional hand. PL-259s are available in solder and
crimp types. Get only the solder type unless you have a $100
UHF crimp tool, then still get the solder type. It makes a
better connection. From the tuner to the
antenna element, use GTO-15 type single conductor wire.
GTO-15 is a high voltage wire with a thicker jacket and
special insulation material rated to 15,000 volts. Since a
SSB antenna can develop much higher voltages than what
standard boat cable is rated for, GTO-15 reduces signal loss
and the risk of shock. The connection at the output of the
tuner is a threaded stud. A properly sized ring terminal
should be soldered to one end of the GTO-15 and affixed to
the stud. Then the whole thing, stud, ring terminal and wire
should be wrapped with a self sealing waterproof tape such
as 3M 2242. 2242 is a soft tape with a 200% stretch factor,
and boy is it watertight. As the GTO-15 leaves the tuner try
not to run it close to other wires and metal objects. You
will usually exit the hull with a watertight through deck
gland of some type and then to the antenna element. If you
are going to a insulated backstay, strip off 3" of the
GTO-15 insulation, wrap the conductor around the swage
several times and clamp with a small hose clamp. The last
step is to wrap with the sealing tape. KEEP THE CONNECTION
DRY and it will last! If your backstay is wire rope, clamp
onto the swage and not the wire rope. The fact that the
swage is a smooth surface enables better surface area
contact with the wire and it will provide for a better seal
with the sealing tape. To further reduce the amount
of RF energy absorbed by the boat, standoffs can be
fabricated to support the GTO-15 away from the backstay
between the deck and the insulator (figure 3a). By following some basic
guide lines and techniques a high performance Single
Sideband radio installation can be achieved with a little
extra effort. Good quality materials improve performance and
can greatly extend the life of the installation. The quality
of the installation will impact your satisfaction with your
radio purchase, not to mention the fun and piece of mind in
being able to make long distance communications from
anywhere on the globe.
ERIC STEINBERG is the
owner of Farallon Electronics located in Sausalito,
California. He is an FCC licensed Marine Electronics
Technician specializing in electronic systems on vessels to
150'. His areas of expertise include SSB / satellite
communications, navigation, weather and yacht racing
instrumentation. He is a sought after racing yacht
specialist with in-depth experience on performance boats
from IMS Maxis to Melges 24s. Eric has been sailing since he
was 5 years old and has many ocean miles to his credit
including Hawaii, the Caribbean and the Panama
Canal.
Eric may be contacted at
415-331-1924 (office), 415-331-2063 (fax) or
gofarallon@aol.com
(email). Materials,
manufacturers and outlets for materials in this
article. 150 watt Marine SSB
radio & tuners Icom, SGC and SEA
(@ electronics dealers) Copper ground
strap Newmar, Farallon
Electronics Copper braid, 1"
tubular Farallon
Electronics RG-8U, RG-213,
GTO-15 Ancor Marine
Products (@ electronics dealers &
chandleries) Backstay
insulators Navtec, Ronstan (@
rigging shops) Whip
antennas Shakespere,
Glassmaster (@ electronics dealers &
chandleries) Marine heatshrink
tubing Ancor Marine
Products (@ electronics dealers &
chandleries) Teflon
Tubing Farallon
Electronics Ferrite
chokes Farallon
Electronics Crimp
terminals Ancor Marine
Products (@ electronics dealers &
chandleries UHF PL-259
connector Amphenol (@
electronics dealers & chandleries) 3M 2242 sealing
tape Farallon
Electronics UltraTorch
professional soldering and heat tool Farallon
Electronics Crimping tool for
non-insulated terminals Tool supply
stores ©1998 Eric Steinberg,
Farallon Electronics, ESCO. Return to
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