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Old 04-02-2013, 15:14   #1
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Antenna for SSB/Ham

So I'm in the middle of installing my M802 radio, and I'm cramming for the General amateur license exam later this month.

The ground system will be a KISS with plenty of copper flashing connecting it (although I have been following the controversy on here).

What about the antenna? I have a GAM antenna which doesn't fit my backstay; I'll probably flog it on EBay. The two other choices are a long wire hoisted by a halyard (and I'm installing a new spare halyard at the aft end of my mast truck which will be perfect for this), or cut the backstay, install one insulator at the top of the backstay, and tap at the chainplate.

I don't much like the idea of chopping the backstay, and it's a big thick mutha at 16mm, and the insulators are special order and $$$$$. But it's permanent, no extra windage, and so probably the better way to go. I think our own resident pandit and guru on the subject, Bill Trayfors, recommended this approach.

Before I start ordering a special order insulator, does anyone have any words of wisdom?
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Old 04-02-2013, 15:20   #2
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Re: Antenna for SSB/Ham

I'd go for the insulator and get one with Norseman fittings so you can DIY. Buy a couple extra cone inserts for the fittings to keep in the spares box if you don't have those yet.

I hoist a wire because I have no backstays but I can't sail with that so also have a whip antenna. I always say the wire is better but it isn't really; you would do just as well with a whip antenna which might be cheaper than the insulator.

cheers,
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Old 04-02-2013, 15:49   #3
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Re: Antenna for SSB/Ham

Nick, how nice to hear from you! Haven't seen you around for a long time. Have you been sailing, too far offshore, to post?

I don't want a whip because of the windage (and to be honest, the appearance).

So I'll take your post as a vote for the insulated backstay. Thanks.
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Old 04-02-2013, 15:55   #4
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Re: Antenna for SSB/Ham

If Bill recommended it, do it! You will be hard pressed to find better advice OR options to consider. I run a maximum length backstay antenna and a ground system that incorporates everyting metal below decks with foil connections. If you want a good signal You cant do too much for a ground system.
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Old 04-02-2013, 16:18   #5
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Re: Antenna for SSB/Ham

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Nick, how nice to hear from you! Haven't seen you around for a long time. Have you been sailing, too far offshore, to post?

I don't want a whip because of the windage (and to be honest, the appearance).

So I'll take your post as a vote for the insulated backstay. Thanks.
Thank you, we've been landcruising but back on the water now.

Yes, I would prefer the backstay too, if I would have one.

ciao!
Nick.
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Old 04-02-2013, 16:26   #6
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Re: Antenna for SSB/Ham

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Thank you, we've been landcruising but back on the water now.

Yes, I would prefer the backstay too, if I would have one.

ciao!
Nick.
Landcruising?? And where was Jedi during all of this? Sad and abandoned somewhere?
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Old 04-02-2013, 16:52   #7
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Re: Antenna for SSB/Ham

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Landcruising?? And where was Jedi during all of this? Sad and abandoned somewhere?
Indeed, hidden in a storage yard for 8 months! I need a cleaning, boat-sitting robot but it's all clean again and everything works like it's supposed to, so she's happy again. Back to projects for me!
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Old 04-02-2013, 17:53   #8
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Re: Antenna for SSB/Ham

If your interested in info on antenna google Doctor Antenna he is in Florida has one of the best set ups with a great through hull grounding device.
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Old 05-02-2013, 06:16   #9
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Re: Antenna for SSB/Ham

I have seen several installation of the GAM aantenna on Cats and other boats without backstays. They seem to do the job, but if you have a choice, even if it causes more work, in my opinion the best antenna is a insullated back stay antenna, with your AT-140 tuner, you should have no problems.

The KISS ground seems to work most of the time, but not always.

In addition to the KISS, if you have the copper foil, run some to your metal tanks, below the water line, diesel and hot water heater. The best is run a foil strap from the tuner to keel bolt. That will give you more than enough grounding.

Also a mistke some people make with the M-802, because the ICOM manul suggests it, is trying to run a ground strap between the tuner and the transceiver (black box)... Don't! It will cause problems called "Ground Loop". Just use a normal 12v ground to the tranceiver (black box) and you will be in business.

I would also recommend you look for a book called "ICOM M-802 for IdiYachts" written by Marti Brown. It is writen for the average sailor and explains things much better than the manual on programing and installation.
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Old 05-02-2013, 06:23   #10
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Re: Antenna for SSB/Ham

Recently popular backstay antenna solution is to swap out that inefficient steel backstay for a synthetic. Skip the insulator. Simply stuff a smallish (16ga?) wire up the center of the synthetic. The synthetic is often finished with a smooth black jacket. Riggers do this for probably less money than that insulator.
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Old 05-02-2013, 15:08   #11
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Re: Antenna for SSB/Ham

DH,

You don't need to insulate the backstay. Just tie the tuner ground lug, the backstay chainplate, and a nearby underwater through hull together. Use a 2 to 4 inch wide piece of stainless steel (preferred) or copper strap. Then use GTO15 wire to connect the RF output from the tuner to the backstay at a point 8 feet above the chainplate.

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Old 05-02-2013, 15:19   #12
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Re: Antenna for SSB/Ham

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DH,

You don't need to insulate the backstay. Just tie the tuner ground lug, the backstay chainplate, and a nearby underwater through hull together. Use a 2 to 4 inch wide piece of stainless steel (preferred) or copper strap. Then use GTO15 wire to connect the RF output from the tuner to the backstay at a point 8 feet above the chainplate.

Really?! Never heard of this technique. But the antenna is grounded? How is that supposed to work?
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Old 05-02-2013, 15:38   #13
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Re: Antenna for SSB/Ham

This is a classic antenna design known as a shunt fed grounded vertical. It has been used for decades by broadcasters and the military. The eight feet of wire between the feed point and ground acts as an inductor. This is a common method of feeding/matching vertical antennas.

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Old 05-02-2013, 15:45   #14
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Re: Antenna for SSB/Ham

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Originally Posted by Viking Sailor View Post
This is a classic antenna design known as a shunt fed grounded vertical. It has been used for decades by broadcasters and the military. The eight feet of wire between the feed point and ground acts as an inductor. This is a common method of feeding/matching vertical antennas.

Very cool! Anyone try this on a sailboat?
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Old 05-02-2013, 16:05   #15
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Re: Antenna for SSB/Ham

I have used this setup since the late '80. It has worked extremely well over the years.

Here is a link to a paper on broadcast antennas using this design:

http://www.hatdaw.com/papers/Dawson_...E_BTS_2010.pdf

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