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Old 03-06-2015, 08:52   #1
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Recommended coax for triatic stay HAM antenna

Tired of rigging/unrigging my temp antennas, I'm going with the triatic stay antenna. I need to order the coax to pull down the mizzen to the tuner/radio.

Any recommendation on antenna coax? I'm guessing I want ancor? This is a pricey install and I don't want to have to do it again.
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Old 03-06-2015, 09:02   #2
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Re: Recommended coax for triatic stay HAM antenna

Sorry, I don't understand exactly what you are planning to do ?

How will you connect to the triatic stay ?
What type of tuner do you have ?

I struggled with antenna placement on my Ketch and ended up using one leg of the split main backstay; It was a compromise.

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Old 03-06-2015, 09:27   #3
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Re: Recommended coax for triatic stay HAM antenna

I've got a LDG Z-11Pro II...should I use LMR-240?

The boat has a small antenna on the mizzen now, it runs to the nav table but I have no idea what kind of cable it is. It's white and labeled "NEWMAR NEWPORT BEACH" and has an Amphenol 77175, which appears to be a 50 ohm connector.

I was going to use this to pull the replacement cable in, unless this cable is suitable. I have no idea if it was for a weather fax or VHF or what. PO crossed the bar.
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Old 03-06-2015, 12:49   #4
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Re: Recommended coax for triatic stay HAM antenna

I emailed Newmar and got this response:



Back in the 1980ís Newmar sold RG-8/ RG 58 cable in 500í rolls to the electronics dealers, this is of that vintage. We have not sold this cable in 25+ years . Based on its age we advise you to replace.
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Old 03-06-2015, 13:13   #5
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Re: Recommended coax for triatic stay HAM antenna

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Originally Posted by autumnbreeze27 View Post
I've got a LDG Z-11Pro II...should I use LMR-240?

The boat has a small antenna on the mizzen now, it runs to the nav table but I have no idea what kind of cable it is. It's white and labeled "NEWMAR NEWPORT BEACH" and has an Amphenol 77175, which appears to be a 50 ohm connector.

I was going to use this to pull the replacement cable in, unless this cable is suitable. I have no idea if it was for a weather fax or VHF or what. PO crossed the bar.
Is the small antenna a VHF antenna ?

Something similar to this:

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Old 03-06-2015, 14:29   #6
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Re: Recommended coax for triatic stay HAM antenna

Exactly what sort of antenna do you propose feeding with this co-ax? Not so many types of mullti-frequency antennae are fed with co-ax. If what you have is really just an end-fed long wire, co-ax is not what you want. more details are needed.

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Old 03-06-2015, 15:21   #7
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Re: Recommended coax for triatic stay HAM antenna

Attached is a pic.

I talked to a rigger, he suggested we use the triatic stay because it was long enough (he estimates around 30ft+, haven't had time to do the math and check it)

He's going to insulate the stay, so how do I get it from the top of the mizzen to the tuner?

In my picture, the red is the stay, the insulators are the yellow/green circles, and the green line is what I assume I need to connect to the tuner and radio at the nav table in the aft cabin. Blue box is where the icom and Z-11 Pro II are located.

Do I need to get the IC-AH4?
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Old 03-06-2015, 15:41   #8
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Re: Recommended coax for triatic stay HAM antenna

I have seen a ketch with that sort of setup.... had an AT130 or similar at the top of the mizzen....co-ax from there down..
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Old 03-06-2015, 15:44   #9
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Re: Recommended coax for triatic stay HAM antenna

What radio do you have? As far as I know the AH4 only tunes ham bands.

My coax ashore and afloat ( from midships to tuner in lazzarette(sp) ) is 8X... works OK.
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Old 03-06-2015, 16:00   #10
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Re: Recommended coax for triatic stay HAM antenna

I've got a IC-7200.

Does that mean I have to run control wires up the mast too? GRRRR
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Old 03-06-2015, 17:06   #11
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Re: Recommended coax for triatic stay HAM antenna

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Originally Posted by autumnbreeze27 View Post
I've got a IC-7200.

Does that mean I have to run control wires up the mast too? GRRRR
'Fraid so... but that would be the case with an ah4 as well

The other option would be to bring the ant from the main to the top of the mizzen and then down to the deck... or just go from deck up the mizzen peak which would be what I would probably do.

OK so that is a vertical but you pays your money .. you makes your choices....
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Old 03-06-2015, 17:14   #12
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Re: Recommended coax for triatic stay HAM antenna

autumnbreeze27,

Sorry to say, your basic plan is not workable
, i.e., to run coax from the tuner to the top of the mizzen mast and then connect to an insulated triatic. BIG WASTE OF EFFORT AND MONEY. Signal losses with such an antenna would be horrendous, no matter which coax you choose.

By the way, the antenna starts AT THE TUNER. All that coax running up the mizzen would be part of the antenna....and a very lossy part at that.

The question is not "which coax to run?". Rather, it should be, "what kind of antenna to rig?".

A much better plan is one like my friend, Scott, has on his 60' ketch. He insulated one of the shrouds for the mizzen and used that for the lower part of his antenna, then put a jumper between the top of that shroud and the insulated triatic stay.

This means that the whole shebang from the chainplates on the mizzen shroud to the top of the triatic is the actual antenna.

You could then install the tuner belowdecks and feed the chainplate.

This yields a MUCH more efficient multi-band antenna. Scott uses his for both ham and marine nets, with great success.

HF antennas on a ketch are quite difficult to rig, especially if there are permanent backstays on the main mast. Too much wire and too much interference. I have another very active ham friend on a smallish ketch who has that problem. No matter what he tries, his signal strength is always weaker than other similar sized boats with sloop rigs.

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Old 03-06-2015, 17:33   #13
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Re: Recommended coax for triatic stay HAM antenna

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Originally Posted by El Pinguino View Post
I have seen a ketch with that sort of setup.... had an AT130 or similar at the top of the mizzen....co-ax from there down..
Putting a remote tuner at the top of the mast is by far preferable to the other alternatives suggested here as it will eliminate most losses in the feed line.

Although you could feed the entire stay configuration, the active antenna portion will be lower.
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Old 03-06-2015, 17:40   #14
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Re: Recommended coax for triatic stay HAM antenna

I was investigating using a shroud and connecting to the chain plate, as that seemed like a good setup. I thought I would just need one isolator... but nope... I'd need 2 more, which means screwing with a second shroud, which adds even more expense. (The shroud I want to use that goes to the top of the mast shares the same chainplate as a shroud that goes to just below the spreader)

So I think going with a chainplate/shroud/triatic is cost prohibitive. The admiral is not in favor of a 23' whip on the stern, so that leaves putting a tuner on the top of the mizzen mast. So what tuner and what cables do I need to connect it? Just go ask the HRO guys?
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Old 03-06-2015, 17:54   #15
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Re: Recommended coax for triatic stay HAM antenna

Putting a tuner atop the mizzen mast is workable, but not as cheap or easy as it sounds.

Coax choice isn't critical...your main concern is physical strength. RG-213 or RG-214 would work fine; so would LMR-400 or even LMR240. RF losses at HF frequencies are not large (unlike VHF).

What tuner? The SG-230 would be a decent choice, but you've got to get 12VDC to it. The Icom tuners like the AT-130 & AT-140 would be good if you've got an Icom radio, but the control wire would need to be extended a long way. These tuner get their 12VDC power from the control wire. Either way, you've got to run: (1) the coax; and (2) the control wire for the Icom tuner or 12VDC wires for the SGC.

Other tuners could work, of course, but you've got to be concerned about using those which are impervious to weather and the marine environment.

As I said, not easy to rig a good antenna on a ketch :-(

I understand the problem with the shared chainplate. Damn! Two insulators would be needed for the shroud....about $600.

Another option would be to forget the triatic and just use an insulated shroud, either on the mizzen or the main. Unlike VHF, height of antenna isn't really important for most HF communication. In fact, the lower part of the antenna is more important for low-angle DX propagation.

A vertical on the stern could work very well, if the XYL could be convinced.

Otherwise, you're stuck with difficult and less-than-optimal choices, IMHO.

Bill
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