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Old 07-04-2019, 07:54   #16
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Re: Marine HAM

I looked at your boat on Sailboatdata. I took the image and put it Visio and scaled 1:1. You have from mast head to deck 55ft of backstay. You want 10' above deck so 45ft of usable length. Many have recommended 43ft for SSB comms if you go the RF Choke/UNUN route. You can do the math from there.

If you decide to cut your backstay, make sure you account for the GTO15 length from the tuner to the feed point on the backstay. The GTO15 is part of the antenna, and as mentioned before, the antenna starts at the connector on the turner.

Personally I would never cut the backstay. I would use an alternate backstay as described by Soonersailor. That would be a randon length of wire running from a spare halyard to the top of the mast.

I need to make a correct. That would be any multiple of λ/2, or even multiple of λ/4.
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Old 07-04-2019, 09:27   #17
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Re: Marine HAM

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Originally Posted by ronstory View Post
Note: that's for ham bands and for the lower bands (80m) you will need longer wire length than most of us have at 84ish feet.
This does depend on the ATU and the antenna length. An antenna that is far "too short" for the lower frequency bands can frequently still be matched by the ATU. This is definitely the case on my boat. Some are under the misconception that there are large efficiency losses under those circumstances, but in reality there are not - although an effective and low loss RF ground or counterpoise becomes more critical. ATU losses rarely exceed 10% if it can get a match, and this is insignificant as a practical matter. What you do give up with antennas that are "too long" or "too short" is a radiation lobe at low angle containing most of the transmitter power, which is ideal for long distance contacts, but that doesn't mean that they are ineffective.

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Old 07-04-2019, 11:37   #18
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Re: Marine HAM

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Originally Posted by SoonerSailor View Post
Plenty of good advice here. Trust your cardiac device tech more than us however!
Indeed, I do.

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If your interest is data and routine voice, you canít go wrong with the M802. If you are a ham contester, DX chaser, or CW guy, you will want a ham rig.
Yes, that is exactly what we want. Above all, it has to be simple.

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You can save a lot of money by foregoing an insulated back stay installation and raising a separate halyard antenna with a little masthead block instead. Easy to do if you are inclined.

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Interesting. So, I would simply hoist it when I wanted to broadcast, or it would be permanent? I'd prefer a permanent solution, but this is interesting.

Only reluctance is getting RF burns. Is that a possibility?
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Old 07-04-2019, 12:47   #19
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Re: Marine HAM

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Interesting. So, I would simply hoist it when I wanted to broadcast, or it would be permanent? I'd prefer a permanent solution, but this is interesting.



Only reluctance is getting RF burns. Is that a possibility?


I leave mine up all of the time. The antenna itself I made out of stainless steel lifeline, with SS cable clamps, and Dacron for a halyard. Also about 2 feet of Dacron line attaches the antenna to the pushpit rail.

I donít worry about RF burns. Maybe I would if carrying for hire, but I donít. No one on my boat is going to be reaching up for the antenna during during the brief periods Iím transmitting. If that is a concern, just make the end of the wire high enough to be out of grab range.
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Old 07-04-2019, 12:54   #20
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Re: Marine HAM

Or you can use vinyl coated wire rope (another name for lifeline).
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Old 07-04-2019, 13:06   #21
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Re: Marine HAM

I donít think I would count on that thin vinyl covering lifeline to be a reliable insulator at RF, though Iím sure it would help to some degree.
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Old 07-04-2019, 15:24   #22
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Re: Marine HAM

It's relatively simple to make a stand off antenna attached to the backstay. All you need is small diameter PVC cut to short lengths, zip ties and wire. Cut the PVC to 1/2' or more lengths as stand off insulators, use the zip tie around back stay through the PVC and cinch the antenna wire to the set up. You'll have to experiment with spacing but 1' or larger spacing should work.

Unless you're really a dedicated Ham radio person. 20 and 40 meters will probably be the only frequency band you'll be using. Most any length backstay over about 20' will work as the tuner will make up for impedance mismatch. The longer the better up to a point but have had good luck with backstay lengths between 30' and 40' not including the tuner to antenna run.

My old Atlas 215 with a Dentron manual tuner had a wire run of 15' or more from tuner to the backstay and worked fine with a little adjustment. Did take an electrical engineer who'd help design the radio to modify the tuner so the radio would transmit, though. Interesting the people you meet in Taiohae. The Icon 718 and SGC tuner are connected with coax and the tuner is at the base of the backstay. Worked fine out of the box.
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Old 07-04-2019, 17:27   #23
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Re: Marine HAM

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It's relatively simple to make a stand off antenna attached to the backstay. All you need is small diameter PVC cut to short lengths, zip ties and wire. Cut the PVC to 1/2' or more lengths as stand off insulators, use the zip tie around back stay through the PVC and cinch the antenna wire to the set up. You'll have to experiment with spacing but 1' or larger spacing should work.

.


I found the black poly pipe used for garden watering systems works well. Light, cheap, easy to cut. Looks smart in black. Not sure how it will hold up against UV but no problems two or three years in.
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Old 08-04-2019, 11:24   #24
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Re: Marine HAM

I just got off the phone with my heart tech guy. He had a brilliant suggestion.

For the $4000 budget I've set for the SSB, plus the modifications to the boat, and the ongoing issue of being in the danger zone, he suggested I look into a satellite phone. He says sat phones use a completely different frequency that will not effect my CRT-D.

My immediate reaction was the expense and the coverage. But wow! Those have come way down!

https://satellitephonestore.com/cata...-phone-kit-322

If I buy the 1 year @ $1,057, it's a 1200 minute package that includes the phone. This would give us 100 minutes a month, for 4 years based on our SSB budget!

No muss, no fuss, no dangerous antenna to stand too close to, ....and I will sleep well at night!

I had no idea the cost had dropped that much! And the coverage........!!! Wow!
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Old 08-04-2019, 11:49   #25
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Re: Marine HAM

Don't forget the cost of roaming and possible landing rights fees, if any. That will eat into your budget real fast. Also, you may require to hold a license to install, operate, and maintain you satellite phone. And then there might be countries that ban the use of satellite phones because the frequencies are used for something else. Oh the complexity of it all.
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Old 08-04-2019, 12:23   #26
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Re: Marine HAM

Sat phone is a good solution if you aren't interested in talking to other cruisers or on any of the maritime nets while underway. And without an M802 you have lost the incremental safety benefit of HF DSC.

If you go that route, consider at least an inexpensive ham radio installation to go with it. A used Icom IC-706, IC-7000, IC-7100, IC-718 or something of that ilk, and the Icom AH4 tuner along with a halyard antenna and you are in it without such a big layout.
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Old 08-04-2019, 12:34   #27
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Re: Marine HAM

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Originally Posted by SoonerSailor View Post
Sat phone is a good solution if you aren't interested in talking to other cruisers or on any of the maritime nets while underway. And without an M802 you have lost the incremental safety benefit of HF DSC.

If you go that route, consider at least an inexpensive ham radio installation to go with it. A used Icom IC-706, IC-7000, IC-7100, IC-718 or something of that ilk, and the Icom AH4 tuner along with a halyard antenna and you are in it without such a big layout.
I hear what you, but if I don't need one to stay connected with family, it ain't goin on da boat. Instead, we will welcome cruisers as we meet them. As it is, we will have a VHF with the antenna mounted on the masthead.

As to the various costs of a sat phone, so much has changed. I just got off the phone with a sat phone tech. Indeed, the $1057/year is for 1200 minutes throughout the South Pacific. And for another $120/year, incoming from family in the US has no extra charges. They are waiving the connection fee, incoming texts are free, and by connecting to a US based international number, outgoing texts are also free. Did I mention the phone was free too?

Yup! I'm in!

Oh! And the only 2 countries who have restrictions on sat phone use are Cuba and India, ....and we have no plans to go anywhere near either.
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Old 08-04-2019, 14:17   #28
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Re: Marine HAM

Glad you got it figured out.
Fair Winds!
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Old 08-04-2019, 14:25   #29
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Re: Marine HAM

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Originally Posted by CptCrunchie View Post
I hear what you, but if I don't need one to stay connected with family, it ain't goin on da boat. Instead, we will welcome cruisers as we meet them. As it is, we will have a VHF with the antenna mounted on the masthead.

As to the various costs of a sat phone, so much has changed. I just got off the phone with a sat phone tech. Indeed, the $1057/year is for 1200 minutes throughout the South Pacific. And for another $120/year, incoming from family in the US has no extra charges. They are waiving the connection fee, incoming texts are free, and by connecting to a US based international number, outgoing texts are also free. Did I mention the phone was free too?

Yup! I'm in!

Oh! And the only 2 countries who have restrictions on sat phone use are Cuba and India, ....and we have no plans to go anywhere near either.
In your specific case I think a Sat connection is a good choice. I would do some shopping around, as there are a lot of options. Try to keep the contract lengths and equipment price down, as the technology is changing quickly, Iridium Next.
Depending on where you plan to cruise, you might want to install an HF receiver. This will let you listen in on any SSB cruiser nets that might interest you or be of value while on passage, as well as listen to shore based voice weather forecasts that are specific for local areas.
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Old 08-04-2019, 14:38   #30
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Re: Marine HAM

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Depending on where you plan to cruise, you might want to install an HF receiver. This will let you listen in on any SSB cruiser nets that might interest you or be of value while on passage, as well as listen to shore based voice weather forecasts that are specific for local areas.
Good idea. Any suggestions? Is a police scanner the same thing? I have one, just never used it.
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