Advice for SSB antenna needed

[Mexican Hat]

Many thanks to John for the sticky on installation. I am following that as closely as I can.



I have a Wharram gaff rigged schooner catamaran. I am in the process of installing my SSB (Icom 710RT with AT 130 tuner, open for Ham bands). The tuner is in the cabin, just a foot from the bottom of the stay and the copper strip sea-water ground will be directly below it. All the standing rigging is dyneema. The aluminium masts are both about 30 feet and the stays correspondingly short. I plan on doing some variation on a rope antenna hoisted up to the top of the mast, running up one of the dyneema stays. I am a bit lost when it comes to the antenna. I am no guru and the more I read, the more confused I have become.


With the short stays, I cannot get close to the length suggested in my Icom manual. So, will the 30-odd feet be adequate? If not what options might work? I could potentially run the antenna wire down the opposite stay, maybe run it horizontally to the top of the foremast, though this involves avoiding the gaff and is probably not possible.



TIA

[K1MGY]

I don't know the physical layout of your boat. Would an inverted V work? It has a nice 50 ohm nominal impedance, and if you have 30 ft up, now you have 60, which allows for a reasonably-tunable 40M antenna. (If you want to go any lower, an end fed - vertical - with a big coil at the base will get you there).

See this entry: https://www.cruisersforum.com/forums...tay-76912.html

I have a Hunter 42 and added a back halyard just for this purpose. Of course, haven't tested it yet.

/k1mgy

[Jammer]

Originally Posted by Mexican Hat

With the short stays, I cannot get close to the length suggested in my Icom manual. So, will the 30-odd feet be adequate? If not what options might work? I could potentially run the antenna wire down the opposite stay, maybe run it horizontally to the top of the foremast, though this involves avoiding the gaff and is probably not possible.

Will 30' work, yes. Not especially well, especially not on the 4 MHz band. You'd lose more than half of your transmit power.


Probably your best choice is to run your antenna along the toerail (use insulated wire) to one of the stays for the forward mast since it is the overall length that matters most. You can pull wire through the center of the dyneema stay so that the antenna becomes a permanent part of the rig and you don't have to hoist it every time you want to use it.

[team karst]

I also have the 710 RT. Teamed with a 23’ whip. Consistently good signal reports into 14.3 after sunset. Also decent on 40, on WWnet. I cant imagine additional wires aloft, unless temporary

[Mexican Hat]

Thanks for the replies. I had thought of the dipole but getting the coax up to the mast top would be problematic for a few reasons. Don't have close to 90 degrees either which raises the issue of potential interference. Still on the possible list though. I was thinking I'd probably end up with a whip, at least at first. Then I can experiment with various lengths of wire and figure out what works.