HF Whip antenna for a sailing yacht?!

Discussion in 'General Technical Questions and Answers' started by KJ4CRY, May 11, 2008.

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  1. KJ4CRY

    KJ4CRY Ham Member QRZ Page

    I am new to HAM and want to operate an IC 706 with AT 180 on my 50' saling sloop.
    What would be the best antenna to warrant long distance reception? Anybody ou there with experience?
    toelpel@teleline.es
     
    Last edited: May 11, 2008
  2. AD5ND

    AD5ND Ham Member QRZ Page

    If the mast is aluminum. You might be able to disconnect the ground and feed it there.
     
  3. K5END

    K5END Ham Member QRZ Page

    The best method would depend on how your sloop is rigged and the material of the masts. At least you won't have to worry about tall buildings or the landscape. :cool:

    I've heard of insulated stays used as a sloper or inverted V, and they say it works pretty well if done right. You could have different stays tuned for various bands as long as they are sufficiently separated from each other.

    If you're rigged as a yawl, the mizzen, with some radials added, could work as a monopole. I've heard that has been done, but never have seen it. That may work for a ketch also, but it may be too close to the main.

    edit added. by the way, there is a group or website, or two, or three, for land lubbers and blue-water sailors to get together & set up appointment contacts, for several obvious reasons. i'll ask my sailing-ham friends and get back with you. surely someone on the forum knows how to do this.
     
    Last edited: May 11, 2008
  4. KW7RF

    KW7RF Ham Member QRZ Page

    Yes, Inverted V

    I would have to agree that an inverted V would be the best choice.
     
  5. K3WRV

    K3WRV Guest

    I've done a few of these for friends or folk who dropped into our local 15 M net in Annapolis many years ago. From experience, I cann tell you that there is no one "Cut and dried" method that both radiates well and doesn't screw up ur boat speed (think 10 M groundplane on top of the mast) or get in the way of something. Feeding the backstay sometimes works, but running the feedline can be a pain. Feeding the backstay and the jibstay as an inverted OCF v also works, but you'll need to insulate things or run a "pseudo gamma match" which sometimes interferes with the sails going up and down.

    If you're new to ham radio, try building some antennas on land and see how they work before trying it on a boat. Buy an antenna analyzer (or at least a grid dipmeter) and get ready to play with antennas rather than sail for a Summer. You WILL get it figured out, and you'll learn a lot in the process, but itr won't be easy!

    One hint that often worked, is to run a length of coax around the inside of the hull, right at the wterline, and bond everything to it - keel, engine block, and whatever else there is.

    In full disclosure - I set one guy up for a "round the woreld" trip, and have never heard from him since!

    de Bob
     
    Last edited by a moderator: May 11, 2008
  6. KA4DPO

    KA4DPO Ham Member QRZ Page

    A couple of things here. First, you can certainly use the 706 on your boat but it won't last. I know a lot of guys who used regular HF rigs on their boats and evetually the salt air will take it's toll. Get a marine rig if you wan't reliable operation.

    Next, the best maritime antenna for any sailboat (in my experience is a backstay antenna from the main mast to a point on the stern or backstay. you will of course need a different tuner and the AH4 is perfect for this application and the price won't hurt your wallet.

    Whatever you do, don't unground the mast.....Ever...
     
  7. N3EF

    N3EF Ham Member QRZ Page

    Check over on the Seven Seas Cruising Association web site on their communications discussion board. Here's a quote from someone on there, Bill Trayfors WA6CCA, who has a lot of experience testing different antenna configurations on sailboats:

    "Antenna System. The most effective long distance antenna you can put aboard your sailboat is a vertical dipole. In it’s elementary form, this is a single band antenna which is completely self-contained and doesn’t require any sort of external RF ground or counterpoise. That’s right: you don’t need to put 100sq feet of copper in your bilge, connect all the tanks together, hook up to your lead keel or through hulls, or any of that stuff. Just construct a robust dipole, tune it for the intended band, and you’re good to go. Dipoles can be built for pennies, using any available wire. However, real seagoing dipoles which will stand up to anything the marine environment can throw at them will cost a bit more. I use 1/8" insulated stainless steel lifeline and a special molded center insulator. You can build a dipole for 20 meters for under $35 (about $25 for 35' of lifeline and $8 for the insulator, plus a bit for the Nicopress sleeves). See construction details here:
    http://gallery.wdsg.com/Marine-Antennas

    Why spend $35 to build such a rugged antenna when you can build a dipole for $5? Because the marinized dipole will last at least 10-15 years, while the cheaper one might not last until next week.

    OK, a 20m dipole will see you across oceans. You can sit in Tahiti or in the Med and communicate with stations Stateside. But, there is value in being able to use other bands as well, so what about that?

    You can build additional dipoles for some other bands, depending on the size of your boat. A 40m dipole will wind up being about 65' long, and most boats couldn’t hoist one as a vertical antenna. You could use it as an inverted vee however, or as an “L” antenna.

    You could also build an “alternate backstay” antenna, using the same s/s lifeline. Treat this like a regular insulated backstay antenna. You’ll now need two more things: a tuner, and an RF ground system. The tuner can be manual to cut costs, but this won’t be as efficient or as easy to use as a fully automatic one. The RF ground system could be as simple as using your aluminum toerails or the s/s pulpit/pushpit/lifeline complex, or radial wires strung under the decks. Or, you could go the more traditional route and build an RF ground system coupled to the seawater.

    All this can be done incrementally, as you need to. But a simple transceiver and vertical dipole will work great, and even after you have a more complex, expensive, and versatile system aboard the dipole will likely continue to do the heavy lifting."

    Link to communications discussion board

    Eric N3EF
     
  8. K1VSK

    K1VSK Ham Member QRZ Page

    This guy who continually argues in favor of vertical dipoles makes me wonder if he ever really cruised - when i discussed this with him, he sounded quite oblivious to the practical aspects of antenna construction and boat management.

    The vertical dipole is certainly one option but not necessarily practical or useful on more than it's resonant frequency. Consequently, I'd put that option at the bottom of my list as it's only really useful to the dock-bound boater community.

    Over the years, we have used just about every conceivable antenna on our sloop, a pic of which you can see by looking me up here on qrz.com. Among the most effective and practical are the ubiquitous end-fed insulated backstay and the stand-alone whip. As you q pertains to the latter category, my experience is limited to the Icom AH-4 whip/tuner combination which worked well for over 10 years of cruising. The only objection we ever had which was the reason for going from it to the backstay was the humming wind generated noise we could never mitigate.

    Either antenna will work well and my IC735 has survived 17,000 cruising miles so be leary of anyone who advocates the use of so-called marine radios.

    Have fun with the RF field generated effects onboard and the ground loops.
     
  9. W7GIB

    W7GIB Ham Member QRZ Page

    I spent many years in the Navy and we used verticle Whip antennaes on 65 foot patrol boats for HF work. Mark III Patrol boats for anybody who is curious.

    The Idea of UNGROUNDING the mast is not only silly, but very dangerous. Think very large rod and fur trick.

    Luckily being a sail boat, you actually have a naturally high point to work with, complete with rigging to get you to the top safely.

    Good Luck.
     
  10. KA4DPO

    KA4DPO Ham Member QRZ Page


    If your IC-735 has lasted that long consider yourself lucky. Several friends of mine in Florida tried to run ham rigs and none of them lasted more than a year and a half before corrosion began to cause problems.

    I'm not advocating a marine radio but I am suggesting it since they are built for that environment. All of the newer marine rigs will operate in the ham bands, granted programming can be a pain on some of them. I never had any RF problems and only used the engine and a copper strip in the quadrant compartment as my ground.

    By the way, I saw the picture of your boat. She's a beauty.
     
  11. K5END

    K5END Ham Member QRZ Page

    Would have to agree there, unless of course you want to play harps and sail the clouds.
     
    Last edited: May 12, 2008
  12. K5END

    K5END Ham Member QRZ Page

    As far as radials, would dragging a long, bouyant copper wire in the drink behind the stern add anything to the party, or would it just give a man overboard something slippery to grab onto?:rolleyes:
     
  13. WY6K

    WY6K Ham Member QRZ Page

    I cruised for six years half way around the world in my 55' ketch. I had an IC-706, an insulated backstay, an AL80 kw amp, a Vectronics manual tuner and an Icom auto tuner (only handled 100 watts, don't remember the model #).

    Everything lasted in the saltwater environment, and the tropics, without problems. I suspect those people who were cited as not being able to keep ham gear working in Florida do not have that gear in a well protected spot. Perhaps they have smaller boats which don't have good nav stations. I've never heard of any long range cruisers who have had serious corrosion problems with ham gear - and certainly not any worse than with other electronics on the boat. It is important to be very serious about preventing ANY salt spray from ever getting on, or even near, the gear. Actual salt water is deadly and you can never really stop it once it's started - I don't care how much WD40 and contact cleaner that you use. So keep it dry! But if the nav station is well protected and never gets any spray or drips, a 706 will not have any trouble.

    The insulated backstay on my boat was not terribly effective. It worked both on marine hf frequencies and ham frequencies (with the tuner, of course). But it was not a "hot" antenna by any means. I used it seriously for getting weather info via HF weather nets on marine frequencies. But for serious communication I used one of the two sat phones on the boat. I know others who have very effective backstays - evidently depends on the details of the rest of the standing rigging.

    I made some dipoles for different bands and hoisted the center up the mast with a halyard and tied one end to the bow and one end to the stern. They worked great! But, of course, the dipole had to come down any time we went anywhere. This is not a really big deal though. Our typical modus operandi, and that of almost all the cruisers we knew along the way, was to sail one day to the next island, stay a month or two on that island, then sail a day to the next one, and stay a month or two on it, etc. So the actual sailing time is not a large percentage of elapsed time.

    Not only that, when we were making a crossing there was way too much going on to be thinking about hamming. It never even came to mind.

    On actual crossings - our longest was 12 days from Bermuda to the Azores - the dipole was always stowed and the backstay was adequate for the hf weather nets etc. But, as I said, I used the sat phone for phone calls and email to family as well as weather charts and weathersat photos.

    When hamming, I nearly always ran heat (the AL80), largely to try to make up for the lame antennas. This meant there was more RF running around the shack (errrr boat) than you can probably imagine. It got into the navionics, etc. (It was actually kinda fun to screw with whoever was at the helm - either my wife or kids - by transmitting and watching the autopilot go nuts.) The screws on the AL80 heated up (from all the RF that wasn't going out the coax) enough to burn my finger pretty badly when I would have a fit of amnesia and touch one of the screws. I branded myself this way about once a year. I tried lots of different things and it never really got any better. I had a large grounding plate added to the stock one, used 5" wide copper foil, concentrated on avoiding ground loops etc.

    I like the idea of a vertical dipole, but I never tried it. Should work on the higher bands.

    About the hf whip: I have one on the power boat I have now and it works ok, but I've never really tested its performance by asking much of it. (BTW, I have a 706 on this boat too.) I've seen hf whips on only a few sailboats. It's not popular and I'm sure there are good reasons for that. I don't like it much because I think it will be in the way and it looks funky. But it should work pretty well because the ocean makes a good ground plane.


    Mike WY6K
     
    Last edited: May 12, 2008
  14. KA0GKT

    KA0GKT Ham Member QRZ Page

    Many seafaring amateurs use a tuner to load up a mast backstay. If the vessel has a steel or aluminum hull, the antenna can be loaded against the hull and the water around the sloop, specially if it is salt or brackish water.

    If the boat has a fiberglass hull, there usually is a copper or stainless steel grounding plate in contact with the water somewhere, generally on the keel of the ship. This plate can be used to help form a counterpoise, however it must be noted that fresh water doesn’t make a great ground plane for a marine antenna.
     
  15. N6YG

    N6YG Ham Member QRZ Page

    I agree with you on this one. The vertical dipole is a really a waste.

    When I was actively cruising. I found that a simple whip and a traditional seawater coupled ground plane worked the best..
    I've used single band tuned 1/4 wave verticals, insulated backstays, and home brew multiple band verticals.
    the best by far was the 1/4 wave tuned vertical. All that beautiful salt water makes such a great ground plane.

    I even built a homebrew multi band antenna from 1/8 inch Teflon tube and 40 feet of stainless steel wire on a spool.
    The tube was suspended from the backstay. I had a small line threaded in the tube that allowed me to pull the wire up the tube.

    Imagine a primitive manually tuned steppir vertical. I would pull as much wire from a spool located at the base as needed to tune the antenna for what ever band I needed.
    The great thing about the home brew Teflons tube vertical is depending on tack I could easily switch the base from port to starboard to keep the vertical, vertical.
    It was easy I simply had two runs of coax and a switch. the coax exited at a lifeline stanchion that served as the tie of point for the suspend Teflon tube.

    Its hard to explain but it worked better then the back stay and It did not need a tuner it was cheap and easy to replace.
    I had enough material aboard to rebuild it a 100 times over if needed. Funny thing is it never broke.
     
    Last edited: May 12, 2008
  16. K5END

    K5END Ham Member QRZ Page

    Ironically, one type of sailboat is called a "marconi," apparently because of the visual similarity to a marconi type antenna.

    Let's build a square rigger and install a set of dipoles in the yards at equal heights with the masts spaced appropriately to effect a nice horizontal yagi.

    Then to swing the beam, you could "turn the boat," I mean, "steer the ship." :D

    The problem is the antenna beam and the ship's beam would be at right angles...more confusion...:)
     
  17. WY6K

    WY6K Ham Member QRZ Page

    An interesting solution.
     
  18. K1VSK

    K1VSK Ham Member QRZ Page

    That's what we did many years ago when I was assigned aboard the CGC Eagle and it worked incredibly well on 20M. We didn't try phasing the elements in the vertical plane, i.e., on the same mast, at different elevations thereby affecting the take-off angle and although the counterpoise was poor and we ran only 100W input, the signal reports relative to some so-called contest stations with which we competed were quite respectable.

    A vertical dipole aboard any sailboat, regardless of how it is rigged, is an exercise in futility as well as impracticality unless it never leaves the dock unless you can come up with some ingenius system similar to that which N6YG apparently used.
     
  19. KA4DPO

    KA4DPO Ham Member QRZ Page

    Yeah, your right Mike. One was a 51 foot Nauticat, one was a 49 foot Hunter, and one was a 68 foot something or other sloop. Two of them were smaller than yours (4 feet) and all had the Nav stations below deck in well protected areas. The sloop was bristol by the way, even the bilge was dry so I'm at a loss.

    Marine radios are are sealed and designed specifically to operate in damp environments. I've been sailing for quite some time and even with A/C it's still mighty humid on board most of the time. You need to open those hatches one of these days.:p

    John..
     
  20. K5END

    K5END Ham Member QRZ Page

    1.) I think that is very cool, your having served on the CGC Eagle. Isn't that the captured three(?)masted square rig schooner, now USCG, originally commissioned by the Nazis?
    2.) Now, seriously, you rigged dipoles on the yards to create a sort of yagi antenna? I don't see why it would not work, but...no kidding, this actually happened? I believe you, but I may have to claim also to be from Missouri :D
    3.) Anyone familiar with the Nonsuch catboats built in Canada, technically not "sloops," but small single non-stayed-mast craft, wishbone boom, ranging from 18 to 36 feet (more like a buoyant windsurfer than a sailboat) might consider adding a ginpole (correct term?) to the bow and rigging a Kevlar line to the mast head to support a dipole. It might look funny, but I think it would work. I became interested in these, after having windsurfed a few years ago. I've never sailed one, but they look like a lot of fun and easy to sail.
     
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