Temporary ham/SSB antenna

[WE9V]

I would like to get on the ham bands (mostly 10-40M) for entertainment/hobby while at the boat. I am not interested in a permanent antenna install (insulated backstay, split-wire backstay, etc), nor something that must usable while under way. I would like something simple, but effective, at the marina or out at anchor.

Radio is Elecraft K3 with internal antenna tuner. Will likely keep to 100W, but also have the Elecraft 500 watt amplifier and 500W external tuner.

I was thinking of some length of wire hoisted on the spinnaker halyard amidships, with some sort of "downhaul" at a center insulator or coax connector near the rail to keep the wire taut , and a 1" wide tinned copper braid thrown in the saltwater, with RG-8X led through the companionway or portlight. Again, only temporary installation, limited to marina/anchorage. I understand that the internal antenna tuner (not located near the antenna) and a non-resonant antenna will lead to large SWR within the coax and the associated additional mis-match loss, so maybe lower loss full-size RG-8 would be better. I am also aware that the high SWR on the RG-8X may also be an issue (surpass the voltage rating) if I choose to run 500w, so would likely need to upgrade coax should I upgrade power output.

I'd prefer super cheap homebrew versus overpriced commercial solutions or "snake oil". What do you recommend, what have you tried successfully?

While I'm at it, does anyone have a suggestion for a directional 6M antenna? I'm considering activating a rare grid or two. With all of the rigging, I don't think there's opportunity for much boom length if I need to rotate it. Was wondering maybe about a homebrew Moxon. A 2-element would fit in a 6.6 x 2.6 foot area, whereas a 3-element about 6.6 x 5 foot.

73,
Chad WE9V

[lucseawalker]

You could try pulling a long wire (single conductor 16GA ) to near the top of your mast connected to a small tuner (manual or automatic) .. you could also bring up an inverted dipole and connect to tuner or make different dipoles for the different bands you like to operate on.
Have fun experimenting and you will be amazed at the crazy antennas you might improvise might work

[Brian.D]

With the size of your boat, you should have the real estate for a vertical dipole on 20. Possibly one for 40m, or even both. Bill Trayfor did just that on his boat. Here is info on these vertical dipole antennas.

Next is the random wire antenna. A study has shown that either 23.6ft or 30ft seem to work best for broadband operations with a tuner. Probably a manual tuner (mentioned above) would be best.

For operations with a dipole type antenna, recommend a current balun to block common mode currents. Also would recommend a balun to block common mode currents at the input of the external tuner if you are using one.

With regards to your 'braid in the water', Gordon West has recommend using a copper plate to sea water (about 6" depth) for a ground if using a random length antenna. But it might also be a good idea to use one regardless.

Good luck and have fun!

[wholybee]

It is quite common to run a wire through the core of a rope and raise that with a halyard. The rope makes it more durable and coils and stores better.

If your tuner can tune a random wire antenna that is much easier than a dipole and can work on many bands. You will need a ground/counterpoise for a random wire. Just drop a wire with a bit of weight on it into the water.

Not all tuners will tune a random wire. In that case, a dipole inside a rope will work. You could do either vertical or an inverted V.

[Bellinghamster]

I didn't ever wish for more power than my ICOMs 150W, and feel I could have gotten by with significantly less 95% of the time (voice and Pactor). I could listen/talk to the folks on the cruisers net in western Mexico from Auckland.

I ran a long wire from corner of the stern arch to masthead, secured / tensioned at both ends with (3/16) poly cord and plastic insulator. Soldered on an insulated leadwire down through a deck fitting to the tuner below and coax to the radio. This antenna could have easily been hoisted on a halyard if you didn't want it standing "permanently", but it had very little windage and was out of the way so there was no reason to want it removable - the convenience of just being able to turn on the radio and use it meant it got used more.
Be aware - If you run a "hot" antenna wire from a radio-internal tuner through the interior of the boat it'll couple all sorts of noise onto other nearby wiring, possibly damaging other electronics. If you're using your radio on deck or in the cockpit at the end of your temporary antenna, then likely no worries.

[deltaten]

I knew an old ham that only ran a vertical "whip" on a chimney mount. Contacts all over the bands and world......
I can visualize sorta mount using bracket to slugs in the sail track , hoisted by main's halyard. Another option might be a good, hi-gain mobile whip mounted atop on of the VHF extensions to a typical swivel base. Locate at rear transom coming and drop down along safety lines to tie off when not in use.

HTH

[MicHughV]

I used a length of 1/8" galvanized wire encased in plastic, that ran from a short pvc pole attached to the stern pulpit and ran the wire to near the top of my mizzen mast, this can be hoisted by a halyard. the lenght of the wire was about 30'.
I had an auto tuner located at the bottom of the pvc pipe, inside the hull. At deck level was an insulated fitting. My hull, at the time was steel, so it was well grounded, but alternate grounding plates are available.

It worked like a champ across the entire band width. The direction my stern was pointed at made some difference, but it worked regardless of position.

I saw another boat with a similar setup. His tuner was under a cockpit seat, attached to a wire similar to mine. Whenever he wanted to use the radio, he simply hoisted the cable up to near the top of the mast with a spare halyard. Told me he had no problem getting a signal out.

Some options for you...

[WE9V]

Thanks everyone for your suggestions. I am looking forward to trying some ideas out, as soon as the bigger, more important projects are completed. I love resonant antennas, so dipoles are nice, but I'm not too keen on needing several dipoles to cover 10-40M, but maybe a 10/15/20M fan dipole would work nicely, with a 33' vertical (quarter-wave) for 40M to compliment it.

Sure will be different than the stacked tribanders and 40M monoband beam up to 110' back home, but I'm hoping the saltwater will help make up some of the difference.

[SoonerSailor]

I just ran bare 3/32 SS “lifeline” type wire up with a spare rope halyard. The rope is an insulator at the top. At the bottom is an easily adjustable length of Dacron line that is the bottom insulator. Attached via GTO-15 to the antenna tuner in the stern. RFground is copper strap to a bronze through hull. Works fine for me.

[Brian.D]

If you REALLY want to have fun and waste some down time, try building an EFHW (End Fed Half Wave) for 40 meters. It should get you on the other bands but might need a tuner. The farther away from the primary frequency means probably the less efficient the antenna becomes. But, that is the fun of trying to get antennas to work.

Rots-O-Ruck