|Topic Review (Newest First)|
|09-10-2010 11:24 PM|
Not sure I understand your first question. If you choose to use a shroud, and insulate it either at both the top and bottom or just at the top, that's OK providing the chainplate is not shared with another shroud and the spreader has an insulated fitting where the shroud passes thru. There's no need for a halyard in this case, since the shroud is permanently in place.
By "alternate backstay antenna", I mean an antenna that you fashion from a length of wire, preferably insulated s/s lifeline because of it's strength and resistance to the marine environment. It's THIS antenna that you'd hoist with a halyard, and tie off to your pushpit.
Yes, 23' or longer is fine. Longer lengths tend to favor the lower bands, while shorter lengths favor the higher bands.
The tuner is going to be costly, and there's no good way around it. While the LDG and other auto tuners can be had for less than the Icom or the excellent SG-230 tuners, they are not as robust and over time will be sure to disappoint.
Only way I know to have a decent installation with a manual tuner near the rig is to put a high quality un-un (a type of balun) near the base of the antenna and feed coax back to a manual tuner near the rig. You might save a couple hundred bucks that way (a good Un-Un is about $85, a decent manual tuner about $100), but unless you enjoy tuning every time you change bands you'll be better off with an auto tuner. Personally, I'd spring for the SG-230 ($499 new) which will work with ANY HF rig and is superior in several respects technically to any of the Icom tuners.
|09-10-2010 09:56 PM|
1-With the alternate antenna am able to install it on my upper shroud (will be easier install inside cabin)(not exactly sure how the halyard would work for that install).
2- As long as its 23' or more I am okay....correct?
3-Any suggestion on (non icom)(something less expensive) antenna tuner that will work well with the icom radio I have?
RF ground, using one through haul will work well...thatís great I thought I had to do something linking several through hauls and the engine.
Thanks for the help in advance!
|09-10-2010 06:09 PM|
Yeah, insulator failures are VERY rare, assuming they're installed correctly to begin with.
And, there's the Hadyn Insulator solution -- fail-safe.
One insulator near the top of a shroud or backstay works very well. Have done a number of such installations. This allows you to feed the antenna belowdecks at the chainplate. And, if you're really worried about someone getting a buzz from the antenna/shroud/backstay, put a PVC or plastic boot over the first few feet above the deck.
The one-insulator setup won't work in all cases, though. I just finished an install on a catamaran which had two shrouds on each side -- upper and lower -- which were both attached to a single large chainplate. Had to go with two insulators.
|09-10-2010 01:18 PM|
At the SSCA Gam in Annapolis last year they suggested a separate antenna as suggested here or a backstay one but with only insulator (at the top). I am replacing my standing rig in a few weeks and think I will go with the latter solution. The boat has the traditional rig with two insulators but these bits are quite expensive and if you don't need one of them ...
The rigger I am dealing with (Mack Sails in Florida) said he has never heard of an insulator failure.
|09-10-2010 08:34 AM|
I hear you re: additional potential points of failure.
What about an "alternate backstay antenna"? This works very well...had one on my boat for 20 years, and have installed many others on client's boats.
Very simple to implement: use insulated s/s lifeline. Put a small loop in each end, using Nicopress sleeves. Hoist the upper end to within 2-3' of the mast, using either a spare halyard or a dedicated halyard. Tie the lower end off to the pushpit on either side of the boat (whichever is best for installation of the tuner under deck). Run a length of GTO-15 cable from the tuner to the lower end of the antenna.
You will still need a good RF ground. The easiest way is usually to run a copper strip from the tuner's ground lug to the nearest bronze thru-hull. There are other strategies which also work well in lieu of this or together with this one. These include wire radials (and the very neatly designed KISS-SSB ground system), the pushpit/lifelines/pulpit complex, s/s rub rails, aluminum toe rails, etc.
Hope this helps,
|09-09-2010 10:28 PM|
Traditional backstay antenna tend to worry me with putting additional points of possible failure in the backstay. On prior threads they talk about the GAM antenna and I read both positive and negative on it as well.
I have a icom m710 but have not settled on a tuner yet.
Our boat is a 38 irwin cc 1985 and right now just cruising the great lakes. However that will change next season and hopefully be heading to the Bahamas.
|09-09-2010 10:04 PM|
NO....do not do that!
Unlike VHF antennas, SSB verticals belong down close to the water, like on the transom.
Why are you choosing to use a vertical (whip) antenna, anyway, if you have a sailboat with a 47' mast?
You might want to investigate either a traditional backstay antenna or an "alternate backstay" antenna, both of which would likely outperform the vertical on many bands -- and, you'd avoid having a whip antenna flopping about in a seaway.
What kind of boat do you have? What are your intended cruising plans?
What kind of radio? Tuner?
What are you planning for an RF ground?
BTW, congratulations on your new ham license!
|09-09-2010 09:53 PM|
SHAKESPEARE 393 23'SSB ANTENNA
I have a 47' mast and I am looking at mounting this antenna approximately half way up the mast.
Running my line inside the mast to my nav. desk.
I have icom M710 but have not bought the antenna tuner yet.
Will this configuration work well?
I just got my amateur radio license last year so bear with me on the simplistic question.