HF Radio Installation

In the winter of 2002/03 we decided to replace our aging Icom SSB with a new Icom. You would think that installation on a metal boat would be easy. Not so.

We had many problems with stray RF resulting in low output power and poor tuning. We were working with Eric Steinberg of Farallon Electronics and even he was stumped.

Finally Eric put us in touch with Jim Corenman, the author of the AirMail program that serves as the e-mail client running on PCs aboard member vessels of SailMail‘s e-mail-over-HF-radio service. Even though we don’t use SailMail, Jim got involved and solved our problem. Based on Jim’s recommendations we installed line isolators and our radio has never worked so well.

Like what you just read? Get lots more:

Please Share

Meet the Author


John was born and brought up in Bermuda and started sailing as a child, racing locally and offshore before turning to cruising. He has sailed over 100,000 miles, most of it on his McCurdy & Rhodes 56, Morgan's Cloud, including eight ocean races to Bermuda, culminating in winning his class twice in the Newport Bermuda Race. He has skippered a series of voyages in the North Atlantic, the majority of which have been to the high latitudes. John has been helping others go voyaging by sharing his experience for twenty years, first in yachting magazines and, for the last 12 years, as co-editor/publisher of AAC.

21 comments… add one
  • Max Fletcher Mar 14, 2013, 11:50 am

    I am trying to reduce stray RF which knocks out my autopilot when I transmit on SSB. I plan to take your suggestion and install a Radioworks T4 Line Isolator near the SSB. You said you installed line isolators (plural), did you also install one near the tuner? Also, did you install any ferrites on the tuner control wires? Thank you for any additional details. Max

    • steve Mar 14, 2013, 2:32 pm

      Hi John,
      I have a question also. Did you ground the isolators to the battery on your aluminum boat?

      • John Mar 14, 2013, 3:44 pm

        Hi Steve,

        No, we did not use the ground strap isolators because they were not available then. Also, just to clarify, you can’t really ground something to a battery.

        Grounding refers to attaching something to a well immersed metal mass such as a ground plate or a bonding system. Of course if the negative battery terminal is attached to the bond system, as it usually is in a fiberglass boat, then the whole negative side is grounded.

        But in a metal boat, like ours, the electrical system floats, so grounding would mean attaching to the hull. It is safe to do that in an aluminium boat as long as there is no connection that will pass DC current (amperage) between the ground lug on the isolator and the negative or positive sides of the electrical system. (It is OK to dissipate reasonable amounts of RF, through an aluminium hull.)

        • steve Mar 14, 2013, 4:19 pm

          Thanks John,
          I still have a lot to learn for our new aluminum boat when it comes to grounding. So is your SSB grounded to the hull?

          • John Mar 14, 2013, 5:03 pm

            Yes, but only through a properly sized capacitor (a device that passes RF, but is open circuit to DC current).

    • John Mar 14, 2013, 3:35 pm

      Hi Max,

      Yes, we put line isolators in the control lines to the tuner. In fact that solved 90% of the problem. We also put isolators on the the 12 volt lines to the radio, although that did not seem to do as much.

  • Dick Stevenson Mar 14, 2013, 5:28 pm

    John and all, Line isolators make a large difference. We also use a number of torroidal chokes which have helped the computer from occasionally jumping about. I believe the bulge on the power supply cable for most laptops is a built in choke. Life with SSB operation is so variable that it hard to know what makes much of a difference, but my understanding is chokes can’t hurt and likely help with RFI.
    Dick Stevenson, s/v Alchemy

  • Petter ;-) Jul 7, 2014, 12:00 pm

    Having read the recent post on SSB vs. Iridum, I am still considering to install an SSB radio onboard – in addition to a sat.phone.
    If anyone has a good guide on the steps to s successful SSB installation in alu vessels, I would very much appreciate a peak into this “black box” of knowledge. I am starting from scratch with an isolated aft stay.

    • John Jul 8, 2014, 8:56 am

      Hi Petter,

      There are some big challenges involved in installing an SSB on an aluminium boat properly. Assuming you have an isolated ground system you need to isolate the grounding with capacitors. This then sets up a problem with stray RF running around the electrical system and down the control lines to the tuner, which can be a real pain in the neck to solve. It took me countless hours installing chokes and multiple RF grounding points (capacitors between hull and both negative and positive conductors) to get the problem solved. The big problem is that almost no one including professional marine electronics technicians understand these problems and how to solve them.

  • Bill Attwood Mar 28, 2015, 5:33 am

    I hope someone may be able to give me some technical advice.
    As part of Kinsa´s refit I am replacing our old Furuno SSB with an Icom 802. The old radio worked ok, although it wasn´t possible to rig a modem to it, but the counterpoise was definitely less than optimal – a small Dynaplate. I have just finished stripping all old anti-fouling prior to applying CopperCoat. CopperCoat is a special epoxy to which pure copper powder is added just before applying to the hull. The actual quantity escapes me at the moment, but it is in plastic bags, probably 1 kg per liter of epoxy. I know that copper would make the ideal counterpoise, but also know that epoxy is a good insulator. My plan is to remove the Dynaplate, then reinstall it after the Coppercoat has been applied, and while it is still slightly soft. It´s no additional work even if the idea won´t work, but I would love to hear that it will work. There may also be some ideas how even if it wouldn´t work as I plan, it could be made to work. Wild idea – lay a network of copper strands in a mesh around and under the Dynaplate before installation.
    Yours in anticipation,

    • John Mar 28, 2015, 7:40 am

      Hi Bill,

      On your question, I really don’t know. But here’s another thought for you. Why not junk the Dynaplate and go with one of these Kiss-SSB ground planes?

      The SSB purists hate them and say they won’t work, but recent testing at Practical Sailor has shown that the actually work pretty well for both voice and data. Much simpler, no holes through the hull (always a good thing) and no worries about trying to keep the marine growth off the Dynaplate—what’s not to like.

  • Bill Attwood Mar 28, 2015, 10:18 am

    Hi John.
    Thanks for the reply. I was aware of the KISS product, and have researched it as much as possible. As you say, radio experts don´t recommend it, and the information I could find on the internet could only be described as anecdotal. Since I already have a Dynaplate (complete with holes in the hull), I shall retain it, but also have drilled into the encapsulated lead keel, which is recommended by radio experts. However, it would be nice to know if the CopperCoat adds anything to the area of the ground plane. I´ll ask the CopperCoat manufacturers, although their answer may well have to be taken with caution.
    Yours aye,

  • Bill Attwood Mar 28, 2015, 2:05 pm

    Belay the last pipe!
    I have just done what I should have done before asking the question – used a multimeter to test conductivity of CopperCoat. Result = zero. The epoxy matrix is an very effective electrical insulator.

    • Marc Dacey Mar 28, 2015, 2:18 pm

      Always happy to hear the results of field testing. I am in a debate on another forum about stray current and it’s shocking (pun intended) what some handy skippers consider acceptable practices. “Daddy, why is our boat surrounded by dead fish, and why are our zincs bubbling?”

  • Bill Attwood Mar 28, 2015, 2:28 pm

    Hi Marc.
    Although this comment is politically incorrect, I thought it might raise a smile. My regular winter neighbour in the boat storage hall has just had his (motor) boat anti-fouled for the season. The zincs on his hull and rudder (6 in total) are all in brand new condition. They are really well anti-fouled so should look just as good at the end of the season.
    How should I explain this to him without being a clever dick?

    • Marc Dacey Mar 29, 2015, 2:02 pm

      Say as politely as possible: “Do you shower in your pants and does that get you clean?”

  • Bill Attwood Mar 29, 2015, 2:11 pm

    Thanks Marc,
    Good advice!

  • John Oct 3, 2016, 8:26 am

    Hi Petter,

    I’m really sorry to hear about that. Good on you for exposing the situation.

    • Petter ;-) Oct 27, 2016, 8:02 am

      I would appreciate it, if you could delete my negative post regarding Yachtfunk. Would that be possible? Please see explanation below.

  • Petter ;-) Oct 27, 2016, 8:00 am

    In a comment above I wrote about frustration with the company Yachtfunk and its owner Joerg Drexhagen. He has made made contact and explained that he has suffered a serious accident and been hospitalised for an extended period.
    Prior to placing the initial order, Yachtfunk came highly recommended, and as per the explanation these recommendations is valid. Yachtfunk will now deliver the goods as ordered, and I can recommend dealing with them and their purpose develops parts for SSB/HF installations in metal vessels.

    • John Oct 27, 2016, 10:33 am

      Hi Petter,

      Glad to hear it worked out and thanks for coming up again on it. Original comment deleted as requested.

Only logged in members may comment:

Member Login

Forgot Password?

Join Us