In today’s modern world yachts use a SSB for more than just marine
traffic and complying with Cat 1 regulations. We send our email, conduct
business, chat with friends, make free phone patches, and download weather
faxes.
One useful system boaties employ is sending and receiving email through
the use of a Pactor modem. This small box connects the SSB to a computer
allowing text email and small attachments to be transmitted and received
from anywhere in the world on any ocean.
Another useful reason to have a SSB is to utilize any of the many radio
nets. Radio nets are kind of a real life chat room where yachts traveling
the world check in and give updates on weather, local political situations
and other topics relevant to voyaging yachts.
In this article were going to explore “tricks” used by
marine electricians when installing a marine SSB.
SSB installation steps
• Choose a SSB model
• Pick a location for the radio
• Pick a location for the tuner
• Build a ground plane
• Build an antenna
• Test the system
Choosing an SSB
SSB radios are broken down into two basic categories. All-band transceivers
and marine frequency transceivers. In reality most modern SSB radios
are built as all-band transceivers, but then “limited” in
broadcast channels due to local regulations.
Most SSB radios can be “clipped” to “open”
the radio to other frequencies. An Internet search will normally give
you an idea if your chosen model can be “opened” to all
bands. This is important as once you install a SSB you can use it for
a variety of clever applications.
Given a choice I recommend two specific radios. For a straight marine
radio I use the Icom IC-M802. It’s the latest and greatest Icom
SSB and arrives out of the box email ready. This means simply plug the
radio directly into the Pactor modem, add a laptop computer and you’re
ready to send and receive email. The Icom IC-M802 SSB/HF radio can be
“opened” by Icom NZ for a small fee. Be sure to specify
the “VFO” software, as this will allow much more efficient
scanning and use on the amateur bands.
The main body of the Icom IC-M802 is separate from the control head
and speaker. This means the radio body can be remotely located in a
safe dry place while the smaller radio control display is positioned
in a convenient location for daily use.
I also recommend the less expensive Icom IC-706MK11G (soon upgraded
to the 7000 with mini TV screen). This radio is really sold as an amateur
ham band radio, but is often used in place of full-blown marine SSB
because of its small size. It’s as tiny as an older VHF radio,
but it’s a fully functioning SSB. Best of all the Icom IC-706MK11G
also includes a 2-meter option so it can function as an emergency VHF.
This little powerhouse is a favorite among the smaller yachts cruising
the world.
When making a decision between a radio made for the amateur bands or
the marine market we have a few issues to be careful of. First is output
power. A typical SSB like the Icom IC-M802 can broadcast 150 watts of
continuous power while the smaller Icom IC-706MK11G, being a compact
ham radio, only produces 100 watts of transmit power. In practice this
has always been sufficient for most communication.
A larger issue is the number of options a new amateur radio offers.
A seemingly endless array of filters, frequency selections, broadcast
types, and a host of other built in options can overwhelm the new user.
The marine band version on the other hand is so basic yacht owners often
wish for a few more options, like an easy scan mode or a quick squelch
setting or more pre-programmed frequency options.
At the end of the day radio selection becomes a decision for each individual
yacht owner.
Picking a location for the radio
The SSB radio often becomes a centerpiece of daily life aboard traveling
yachts. For this reason the SSB should be located close to the helm
for use in an emergency, but also close to a comfortable seating area
for long chats. When picking an area to install the radio keep in mind
areas that are prone to the occasional soaking by a wave or open hatch
in the rain. The ideal location should also be close to a safe dry place
to connect and view the laptop computer.
Another positive future of sailing with a SSB is they function as a
high quality short wave receiver. This means on lonely night watches
we listen to Radio NZ and a verity of other interesting viewpoints broadcast
from around the world.
Locating the antenna tuner
The antenna tuner is the box that matches a radio signal to antenna
length. A particular radio frequency or channel will want to “jump”
off some antenna lengths thus making a good broadcasting station. A
poor “match” will want to back feed the signal from the
antenna to the radio causing heat and eventual destruction of the transmitter.
The job of the antenna tuner is to make a perfect match between the
chosen radio frequency, and the length of the radio antenna.
The tuner should be located as close as possible to the antenna. To
make this easier Icom antenna tuners are built watertight and can be
mounted on the deck. In use, most owners tend to mount the antenna tuner
in an area below deck where the electronics are safe from the elements.
Remember you will need a path for the 75mm copper ground strap to the
counter poise that we’ll talk about next.
Antenna and counter poise
A SSB antenna is built in two parts, the antenna and the counterpoise.
The antenna is normally considered the easy part, as it’s basically
just a wire run into the air. We’ll discuss the mechanics of supporting
the wire later. For now lets discuss the counter poise.
A counter poise is the half of the antenna that we normally don’t
see. It’s the connection of the antenna to the water. The “ground
plane” or counter poise is the least understood, but most important
and often overlooked aspect of a marine SSB installation. The “ground
plane” provides a “foundation” for the antenna to
“push” from.
Luckily seawater is one of the best radio grounds known. In fact often
we see commercial broadcast antennas located in swampy wetlands. This
is not because the land is cheap, but because of the easy electrical
connection to ground.
Counter poise connection
A yacht SSB installation can “connect” to the grounding
seawater in variety of ways. Lets look at the most common and innovative
methods used by marine electricians.
The traditional yacht counter poise is made by connecting metal surface
area below the water line together to form an “induced”
connection between the seawater and the ground plane (or counter poise).
This means running copper strap to metal water tanks, keel bolts, and
any other metal below the water line.
As tempting as it may be to use the engine as part of the ground plane
many electricians stay away from this for two reasons.
First the engine is also connected to ground through the starter and
alternator so a ground loop is formed. This ground loop most often shows
itself by sending a large amp load through the SSB during engine start.
This is why most SSB’s arrive with a fuse on the negative lead
as well as the positive lead.
Second, in the unlikely event of a lightening strike the immense current
can travel down the backstay, through the SSB, through the ground plane,
into the engine, and out the prop shaft to “jump” off the
sharp edges of the prop. Along this path the engine bearings are often
spot-welded thus ruining the engine.
Copper sheet laid into the hull at the time of building is another
great solution. It’s simply a matter of laying copper foil against
the hull and putting a bit of glass over the top to prevent the copper
from corroding. This is a fine solution to consider during yacht building
but what about a yacht not built with copper laid into the hull?
Gordon West, an American radio guru recommends attaching the SSB copper
ground straight to a single bronze through hull. The attachment is simply
wrapping the copper ground strap around the clean through hull and securing
it with a hose clamp.
Now comes the all-important test. Gordon recommends powering up the
radio, pushing tune and listening to the antenna tuner. You should hear
a series of clicks as the antenna tuner does its job of matching the
antenna to the radio frequency. After all the clicking has stopped push
tune again. You should hear one or maybe two clicks, but the antenna
should be tuned and thus the tuner should be quiet.
Next, take a roll of aluminum foil and remove about 10 meters. Connect
one end of the foil to the ground plane and toss the other end in the
water. You should now have a long stream of foil in the water and the
dry end connected to the ground plane at the antenna tuner.
Push the tune button again and listen carefully. If the antenna tuner
starts clicking all over again then your ground plane is not sufficient
and must be improved. If you only hear a click or two then your ground
plane is sufficient and you’re done with the ground plane installation.
Run this test on any boat if you have a question if the ground plane
is sufficient.
Another common solution to building a ground plane is the use a of
porous bronze block through mounted into the hull. This bronze block
is designed to provide all the ground plane needed by one simple quick
installation. Many marine electricians claim the cost of the ground
plane block is overcome by the fast dependable installation.
Metal yachts have the easiest connection to ground. Simply find a dry
rib, stringer or other area of the hull. Sand the paint to bare steel
and bolt on the copper strip. This connection to ground tends to provide
a near perfect counter poise giving metal yachts big strong booming
signals.
Simple antenna designs
The antenna is the most basic part of the SSB installation. Fundamentally
for a yacht the antenna is nothing but a wire supported into the air.
The higher and longer the antenna the better. If we were to look at
any antenna instruction handbook they all start chapter one with a description
of the “long wire”. Yachts are perfect for this easy antenna
system.
One common method of making a long wire antenna is the use of an insulated
backstay. An insulated backstay is merely using an existing piece of
rigging and having an insulator installed on each end. This is a tidy
installation, but also one of the more expensive for the DIY. Talk to
your rigger to have insulated backstays installed in your yacht.
To connect the antenna tuner to the insulated backstay use length of
high voltage antenna feed wire available at most electrical supply houses.
You should only need two or three meters of this special insulated wire.
The antenna feed wire should not make any tight corners nor should it
run next to any metal. When the antenna feed wire runs up the backstay
a series of stand-offs should be used to prevent energy “bleeding”
into the un-insulated area of the backstay causing a shock hazard and
robbing part of our output power.
Another simple antenna design is to use a length of 4mm yacht braid.
Remove the center core and replace it with a solid wire. Put an eye
on each end of the line and support it with a halyard. This emergency
antenna is now standard on countless yachts as many long-term boaties
swear by this system. Its simple, does not entail cutting the rigging,
and can be made by most yacht crews. The crew can feed the wire into
the side of the yacht braid where it best suites your particular installation.
This makes a good all around insulated antenna. (See sidebar or photos)
The most expensive and often most simple option is to buy a SSB whip
antenna. The advantage is a quick installation and you don’t have
to cut the backstay or support a long wire antenna. The extra tall SSB
whip antenna is most often seen on powerboats and catamarans.
Testing the system
The testing of the installation is the last important step to ensure
the SSB will be able to communicate with the outside world when needed.
The first step is to search the bands for a very weak signal. For this
test you should barely be able to make out the broadcast. Listen for
a few moments till you have a clear idea of signal quality. Push the
“tune” button and listen for the antenna tuner to go through
it’s clicking process. When done the barely audible signal should
have significantly improved. This is because a properly tuned antenna
“hears” the intended signal better and reduces interference.
The next test is to find a radio net and try checking in. By law you
will need to have a station license for the frequency you intend to
broadcast on. Before you attempt to check in take a few moments to listen
and pick out some weak, particularly distant stations. If you can hear
them, and your installation is correct they should be able to hear you.
Ask specifically for a report from the distant station.
The report will probably reply with something like “You are three
by two”. The first number is your readability and the second number
is the signal strength. A good report is five by five. The above-mentioned
three by two is kind of poor. The three means your signal is not very
strong, but since were asking for a report from a week station this
is probably not bad.
If you receive a poor audio signal report specifically ask if the audio
is “scratchy” or “muffled” or “mousy”
or is the audio clear, but buried in the static. This is important as
“scratchy” may be something as simple as the mike too close
to your mouth. “Muffled” could be the radio itself not converting
your voice into a “clean” radio signal. “Mousy”
often refers to a Mickey Mouse sounding signal. This may mean your broadcast
is slightly off frequency, or the radio is “drifting”.
Most likely with a new radio installation and a good ground plane you
should hear a clear, happy “Five by five mate”.
Sidebar #1
Winlink.org gives free SSB email to boaties
Winlink is a volunteer based free email system run by Jim Corneman.
You read that right, free. No hook up charge, no cost per minute, no
buy in and in fact Winlink provides almost unlimited connection times.
Winlink is the amateur radio solution to SSB email usage.
Armature radio means you must have a ham license. At first glance this
license can scare people into thinking about antenna formulas, late
night study, Mores code and crunching numbers. In reality, classes are
taught that take the novice through the license system in just one weekend
and the Mores code requirement has been eliminated.
Once you acquire your license you will never again have to crunch a
number or figure an antenna length. From that moment on it’s simply
riding along on the free email system that works anywhere in the world,
just about any time.
If this sounds too good to be true know that by using the amateur bands
to send your email you are preserving the public bands for future generations.
The amateur bands have been slowly re-distributed over the past years,
as amateur radio interest has declined. The advent of the Pactor email
system in the mid 80’s has seen a resurgent in the public use
of the airwaves giving amateur radio users enough political clout to
again begin preserving the public frequencies.
Another future of the Winlink system is progressive GRIB weather charts.
Send a short text email to the master computer saying for example, your
leaving Tonga, heading for New Zealand and expect the passage to take
ten days. The system will automatically email you twice a day with forecasts
for your exact position but no other area saving download times. You
can even ask for the text of websites to be sent to you every day. This
allows yacht crews to read news headlines, or follow sports scores as
they sail.
If the idea of yet another marine license seems daunting then check
out Sailmail. Sailmail is the commercial side of sending email with
a SSB and Pactor modem. Your connection time is drastically limited
per day and there is a yearly charge, but the system allows simple email
service while you take time to gain an amateur license.
To use the Winlink system the yacht will have to have a relatively
new SSB, a computer, a Pactor modem and a ham license.
For more information see Winlink.org or http://www.nzart.org.nz/nzart/.
Overcoming paint blisters near the antenna ground
Occasionally a SSB will cause electrolysis issues below the water line.
The owner may see paint blisters around the bronze-grounding block,
or on a steel boat the paint may begin to lift. One simple solution
is the use of capacitors inline with the ground plane. Brett Martin
at Icom NZ can install these into your antenna tuner for a small fee,
or you can do an Internet search and build one yourself for just a few
dollars and a little time invested.
A simple DIY SSB antenna
This simple and effective yacht SSB antenna has become a favorite among
delivery captains and cruisers alike. It’s portable but can be
left in the rigging permanently. The antenna provides some insulation
against accidental touching while broadcasting and can normally be made
from spare parts lying around a Yacht.
You will need:
• Approximately 10-15 meters of small diameter yacht braid.
• A length of regular yacht wire to run up the center of the yacht
braid
The idea is to use the cover from the length of yacht braid as the antenna
support and insulation while replacing the core with antenna wire.
Were going to pull the core of the yacht braid out one end of the cover
while at the same time use the core to “suck” or pull the
antenna wire up the center of the cover. In essence were going to trade
the line core for a wire.
That’s it. Put a simple eye splice in each end of the line/antenna
and hoist it in the rigging. In practice the user can pick the height
off deck to feed the antenna wire into the cover. To do this use a fid
to “open” the cover and pull out the core for attachment
to the antenna wire.
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