What HF radio antenna to use?

That's an interesting question. First, we're talking HF, <30 MHz or 10 meter? So, lower frequency, longer wavelength, and the antennas get longer.

On Our Journey, I used about 30 ft of the backstay for SSB. And we're all C-dory here, so there's no backstay. And for a marine vertical stick antenna, they're 23 ft. The good news is that they're in 2 sections, the bad news is that they run from $200 (WM, Shakespeare 390) to $350 (Defender Shakespeare 5301.) And don't forget to use an antenna tuner.

Here's an article on how to use a CB antenna on 10 meters, but only 10 meters:10 meter CB Antenna.

Now if you're talking between 6 meter and 23 cm, that's getting down to a reasonable size, but then that's not HF. VHF is 30 MHz to 300 MHz, UHF is 300 MHz to 3 GHz, so you can see how that affects antenna size.

I'm really interested as to what hams have used for HF on small boats. I'm sure that I'll learn something new.

Boris
AG6MP
 
The "Outbacker" is one of the better HF mobile vertical antennas since it is waterproof and of very rugged construction. Best to locate it at the forward end of one of the cabin top handrails using a mount that will allow antenna to fold down when necessary. Then use some one inch wide copper foil on underside of cabin top and connect it to the handrail through bolts athawartship at fore and aft positions. This arrangement creates the "ground plane" necessary for the vertical antenna to emit sufficient RF power without a high VSWR.
 
N9DXC has it right.

The ground plane is critical for the HF bands. Rails and other typical mounting areas on boats won't do the job. The copper strap is the ticket. There was or is a popular ham by the name of West who put out many books and how to's for ham radio. I followed his guidelines for adding hf to my 32 foot gulf motor sailer, and it worked great. He had formulas for how much copper to add and what lengths.

Search West, ham radio and you can probably track down those specific guidelines. He may not still be alive, but his technical articles are out there.
 
Art,
I have done a bit of experimentation with various small antennas, in comparison to larger full sized antennas on boats. For the C Dory I prefer the "Ham Sticks" They work with a rail mount on the cabin top hand rail. Then you can ground the rail with 2 to 3" wide copper strap, running across the inside of the cabin, and aft to the engine. Not ideal, but probably the best you can do with the small cabin.

As well as Ham Stick, there is Hustler, Pro AM (not sure if Larson or Comet still make HF base loaded types), and I just read that Ham Stick is out of business-but some antennas are still available. I had some issues with the pot metal used in the ends of the loading coils on the Hustlers, after extensive maritime use. But I have worked all of the S. Pacific and Asia, some of Europe with Hustlers mounted on my RV. Also worked from Europe to mid US with Hustlers mounted on the stern of the large sailboat we took to Europe.

However, there is a better way to get around the ground problem--and that is to make a dipole out of the ham stick or other base loaded antenna, such as the Hustler. Here is an article about doing this: http://www.eham.net/articles/2621 I have at least one of the dipole connectors, and have made some my self. Not hard to do. The dipole is rotatable, so it is directional and can be mounted on a short mast, which can be mounted anywhere.

I agree that the Outbacker is a very good antenna, but it is fairly long size, still requires a ground connection (most are used on cars and trucks). One other concern is to use a conductive non corrosive grease on the plugs of the jumper cable.

I did some experiments with the Cal 46, where I had 3 Ham Sticks mounted on a 3 way mount on my Radar Arch, which was 9' off the transom. The entire arch was part of my ground system which also included SS water tanks, about 70' of 3" foil thru out the boat, and Aluminum diesel tanks. I also had a large dyna plate which was just a bit foreword of the Radar arch on the bottom of the boat, which could be switched in. I had rotary switch so I could go from a single wire about 60 feet Stern to masthead--insullated, and not parallel to the back stay. The ham sticks, a 23 foot Shakespeare Marine HF antenna, and a inverted multi band tuned dipole--had to be put up and tacked or jibed, depending on point of sail--from bow, to under spreader (about 30 feet up) and to stern rail. Depending on band and propagation, I would gain 1 to 2 subjective S units when I added in the Dynaplate. (not sure that the drag from a Dynaplate would be worth it in a C Dory, but a flat copper plat could be put in (some issues, with the core and securing the plate).

Often the Inverted V Dipole would give the best signal reports, but nearly equal were the long wire (with tuner), the 23 foot Marine antenna, and the Ham Sticks. Often the receiving station could not tell the difference.
 
Hi Bob, et all;
I presently have an ICOM 706MKIIG with the AH-4 Remote tuner at the home driving a 47' long wire. I plan to drive an "EAGLE ONE" 31' portable vertical ant. to replace the long wire. I then plan to replace this setup and move this '706/AH-4, only, to the CD25.

I have a full set of HUSTLER mobile traps and I don't think they would standup too well to the harsh marine setting, unless I only use them when I'm aboard the CD25. Bob had advised a means of a counterpoise with copper straps. Too bad there isn't a copper strap tape like the AL tape used in HVAC (that I know of).

I plan to go with the TENTEC OMNI VII at home with possibly another AH-4 to feed the "EAGLE ONE" vertical. My home is on a small 75'x100' lot. Yes, I have considered the HYGAIN HT18 Vertical, but having given away 2 that I never raised - my bad - I'll just have to see how all this plays out for now.

So, thus the question of which vertical antennas folks use, both at home and the boat(CD25). My open ended question did awaken some thoughts; including ground plane radial plates and possibly adapting them.

As you may have guessed I'm 'jumping' back into ham radio. I already have added 2Mtr to the car, FT2900R, and liked it so well I replaced my 35yr old 2Mtr at home with the same model. This frees up a 2Mtr, Kenwood, TR7400, for the CD25.

I hope the CD25's electrical system can handle all the RF.

Art
 
Art,
The major problem I have found with HF RF is two fold. One Auto pilots are very sensitive. Second, if you use "braid" for ground strap, instead of the copper strap. Even plumber copper strap is better than "Braid" if you can even find the plumbers perforated straps today. The regular marine type of 2" copper strap is now about $3.00 a foot. If you can find the 3" it will be closer to $5 a foot. This is why the dipole with the bottom loaded whips is so appealing. Also with these you don't need the tuner. I have used both auto tuner (I had a SEA auto tuner for my SEA 223 Marine SSB radio. but I had a switch so I could use it on the ham. With dipoles, and the ham sticks (or Hustler's) I did not use a tuner. I also had a manual tuner for my 12 volt Solid state 600 Watt Amplifier, I used only when we have poor propagation, or there was a lot of adjacent QRM.

Radials will work in larger boats, under the decks. but there is not a lot of room in the C Dory--you could do folded radials--have to do some tuning to get these right, but can be done. There are also folded dipoles--but generally these are too long for the C Dory.

Another antenna I have used on the RV's is the Comet UHV-6. The manual is at:

http://www.cometantenna.com/pdfs/UHV-6_manual.pdf

This is a 2 meter, 440, and 6meter, plus resonators for HF bands. I have not tried a dipole with this…but might be done….some issues. I was able to use it in the RV without setting up larger resonators.

Also I would get a good antenna analyzer for working with any of these antennas. It makes tuning much faster and better: The MFJ 259 B is a good starting point, and will also cover 2 meter.

If you have the hustlers, why not try setting up a dipole--if you have two antennas on a single band. 20 meter for 14.313 Maritime Mobile net Pretty much international. There are 40 meter maritime nets on both costs and mobile in the central US, plus some 80 and even 160 on the West Coast and Mexico.
 
Art,
the real copper plumbers tape, not copper plated. The steel can work--but the copper of course is better. Even better is the 2 or 3" copper tape. I found copper tape at $170 for 50 feet!
 
The mount
Clamps to your railing.

http://www.ebay.com/itm/NEW-BRV1-CB-HAM ... 2a2af33df9



The mast

http://www.hamradio.com/detail.cfm?pid=H0-003402
(the #3 not #1 or #2)

They are 54" tall. Use two of them stacked (108") and then the Hustler coil on top with a whip. Tune by using appropriate coil and adjusting whip length.
Do not use the 1000 watt rated Super coils, they have more loss than the regular coil. And more weight and more windage. A lose-lose.

Might want a stainless steel spring at the bottom
http://www.hamradio.com/detail.cfm?pid=H0-003360

Ground
The rail becomes part of your ground plane. Add to that some copper foil strap radials to improve the antenna efficiency. (thin is fine - thick does not improve it)
You can add two wire radials following the railing or the toe rail around the perimeter of the boat. Even the rub rail will be a good place to run them.
They do not have to be the same length.
Do not connect them where the ends meet up (i.e. form a loop) Leave a gap of a few inches.

General
-An auto tuner will make life better/easier/faster
-You will want a ground wire for static charges / lightning. Just a wire dangling in the salt water works. I use a zinc fish which I have on the boat anyway, hanging over the side.
-Wire under the water does not add to your ground plane BTW

This set up will give you 40 through 10 meters with reasonable efficiency.
And 80/160 meters will work - at lower efficiency but you are sitting on a big ground plane (salt water) so you will be better off than on your car over dirt

Here is an excellent site for information.
His ego is bigger than a mountain but most of the info is good (not 100%)

cheers,
denny - 'doc' on cw
K8DO
pounding brass for 51 years now
 
That mast is what I used on the boat we took to Europe. I certainly agree on the solid "mast" vs the fold down (#1 & #2) that Denny-0 referred to. The Hustlers do develop corrosion on the pot metal which is on the top and bottom of the coils. Maybe coat this pot metal with an epoxy based paint?

The rail clamp is available at radio shack and truck stops, since it is used as a mirror mount clamp for CB radios.

The trick is tying together as much metal as possible on the C Dory for the ground. The aluminum in the rub rail is a great idea, but you do want a solid connection, without leaking. Tying both of the SS rails together with the copper tape helps, but I believe that taking the tape down to the side of the cabin and then taking any radials off of that is best, rather than a next of wires coming down from the terminal point of the railing thru bolt. I both soldered and fastened with bolts any places when I joined the 2" or 3" copper tape to another wire. For attaching the tape to the transmitter, I folded the end over once at a 45 degree, then folded that over at 45* the other way, so there was a 90* point. Sweat soldered this together, and then punched a hole near the end to bolt this to the chassis of the radio transmitter. Hooked the tape back up to the common ground/radial system. In the 22 I would have the HF radio on the shelf over the forward part of the cabin, and take the copper tape back up to a thru bolt for the railing.

These short base loaded antennas are made for autos, RV's and trucks, where you have a large amount of metal. For example in the RV, I tied the ground system into the ladder on the back and then into the vehicle frame, and that worked very well, with a fiberglass body.

KOWJ has some one interesting thoughts--not all of which apply to boats. I noted one of his photos where there are two ham sticks at right angles--the one parallel to the earth being the "ground" of the dipole. I found that the rotating dipole worked better, but either are more difficult on a small boat.

One other thing which was brought to mind from these slides of K0WJ is that ferrite beads over leads do help with noise on the boat. Mostly depth sounder and VHF radio. Also keep all of the radio leads away from other leads, and never run any of them parallel in the same bundle.

My philosophy with lightning, is to get all antennas down, disconnect all electronic leads--including power, and ground, and if possible get out of the area. We have been in some horrendous lightning storms--Yugoslavia we had over 100 strikes within 2 miles in an hour. We had St.Elmo's fire in the rigging. We had chains into the water off each chain plate, and the only thing we lost was one diode in the wind instruments, which were not disconnected…(they were in the future storms). Certainly a zinc "fish" will help to dissipate any static charge--but if you get a direct hit……Stay away from any metal in the boat… One of my boats had 3 direct hits after I sold it. I don't know if the new owner had changed the lightning protection system or not...

Denny-O has a lot more experience than I do, since I only started maritime mobile in 1979, only about 34 years ago--vs his over 50 years.
 
Just a thought outside the box:
The use of CU screen in the cabin, like we use to use in screen rooms for RF secure areas.

I suspect that lining, and bonding, the cabin walls and inside roof would give us a good radar signature as well as some RFI coverage. This screen could be covered over with an insulating paint once glued in place. Practical?? Don't know, but it sure would make a good ground plain for anything on the roof.

I have already installed an extra fuse block in the cabin. I hope to enhance the return (-12VDC) lead back to the batteries this spring. I have some #8 shielded power cable for the radios along with some chokes for the power leads of any and all equipment, as needed.. So far the need for chokes has not been the case.

I was first licensed in 1967 as WN9YPZ and shortly afterwards in Dec 1967 I became WA1KRM. I started mobile HF ops in 1968 with a SWAN 500C and the Hustler 'sticks' , 10 - 80Mtrs, with 40Mtr as my favorite. That was a beast of a SSB rig that would modulate my headlights in the old Pontiac with its 30A DC Generator. My last HF mobile op was abt 1999, so I have a lot of cobwebs to shake out. I got into 2Mtrs in 1974, base and mobile.

Thanks for all the insight, shared experience and help. It took me since 2007 till now to place a radio in my VOLVO XC90. You might say I'm a slow mover, but I'm getting back. ... _._

Art
 
Art,
Not really out of the box with the heavy duty wire screen. We put this into the 38 foot cruising boats we built. (about 30 sq feet), but also soldered the 3" foil to the wire. Most boats put the screen into the hull bottom. (inside)

I know of at least one power boat where there was the screen in the top of the cabin house. But I believe that they have more problems with RF, and eventually added more copper foil. I would probably insulate with foam or some headliner material rather than the paint…but either would work.

I still would go with the foil, and if possible some direct water contact--the outboard or a thru hull fitting. The foil plus screen and water contact would be good.

I would think that a corner radar reflector is better than using screen as a reflector. I may be wrong about that.
 
That is probably as good as you are going to find. I think I saw one place $20 for 15 feet. The 22 mesh screen (what we used) is very expensive. Even #16 is $6.30 a sq foot cut. Mim. order of $75.

I think I still have about 20 feet of the 2" foil left over from my last project--I think it cost about $30 for 50 feet….a long time ago.
 
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