SSB Backstay antenna - Page 2 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Chat  
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #11  
Old 01-27-2010
JohnRPollard's Avatar
Moderator
 
Join Date: Mar 2007
Location: Chesapeake
Posts: 5,680
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 10
JohnRPollard is a jewel in the rough JohnRPollard is a jewel in the rough JohnRPollard is a jewel in the rough
Zan,

I merged them. You can go back and delete any duplicate posts now, if you feel like it.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Pacific Seacraft Crealock 31 #62

NEVER CALLS CRUISINGDAD BACK....CAN"T TAKE THE ACCENT
Reply With Quote Quick reply to this message Share with Facebook
  #12  
Old 01-27-2010
Shortman's Avatar
Senior Member
 
Join Date: Feb 2006
Location: Western MA & Maine
Posts: 167
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
Shortman is on a distinguished road
I scanned the article. I am home with a yucky cold, so I have the time. But I have never had luck posting photos here. It is a jpg 87k, meets requirements. There was a post once about the vodoo req'd to post, but I cannot find it.
Reply With Quote Quick reply to this message Share with Facebook
  #13  
Old 01-27-2010
Cruisingdad's Avatar
Best Looking MALE Mod
 
Join Date: Jul 2006
Location: Washington State
Posts: 9,905
Thanks: 3
Thanked 118 Times in 54 Posts
Rep Power: 10
Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough Cruisingdad is a jewel in the rough
If this is a direct repro of copyrighted material, you can not verbatim paste it here. Sorry. I have no problem with you linking it, but copyrighted material is, well, copyrighted for that very purpose.

Sorry.

Brian
__________________
Sailnet Moderator



1987 Tayana Vancouver 42, Credendo Vides, (Mom and Pops boat, F/T Mobile Live Aboards in Puget Sound)

My Website:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Follow My Blog at:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Follow me on Facebook:

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #14  
Old 01-27-2010
Shortman's Avatar
Senior Member
 
Join Date: Feb 2006
Location: Western MA & Maine
Posts: 167
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
Shortman is on a distinguished road
OK gotcha
Reply With Quote Quick reply to this message Share with Facebook
  #15  
Old 01-27-2010
Senior Member
 
Join Date: Jul 2001
Posts: 1,174
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 14
k1vsk will become famous soon enough
Quote:
Originally Posted by Zanshin View Post

K1VSK - what sort of interactions are you referring to? If I were to embed an antenna into the nonconductive Dyneema, could you envision that the structural integrity might suffer over time? Dyeema doesn't like temperatures of over 150C, could those be reached somehow when transmitting?
The most common form of interaction is parasitic and takes the form of effectively changing both the impedance and electrical wavelength of the antenna. This is a lot more complex set of interactions than is worth going into here but hopefully it will suffice to say that in erecting various forms of antennas over the years, we have found that virtually any material in close proximity to an antenna has an effect.
You will not find any measurable temperature change.

Reply With Quote Quick reply to this message Share with Facebook
  #16  
Old 01-27-2010
Zanshin's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Germany
Posts: 2,217
Thanks: 0
Thanked 17 Times in 17 Posts
Rep Power: 9
Zanshin is on a distinguished road
I found a page on the web showing physical characteristics of Dyneema and they stressed that it makes an optimal covering for radar and sonar as its dielectric constant is a low 22oC/10GHz: 2.25 and Loss tangen: 2. 10-4 {which means nothing to me, but sounds impressive} so perhaps that is a point in its favor if used around a SSB antenna.

Here is the link to the manufacturer's factsheet: http://www.dyneema.com/en_US/public/...ext.src=search
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Zanshin; 01-27-2010 at 11:18 AM.
Reply With Quote Quick reply to this message Share with Facebook
  #17  
Old 01-27-2010
hellosailor's Avatar
Senior Member
 
Join Date: Apr 2006
Posts: 10,972
Thanks: 3
Thanked 107 Times in 104 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
Zanshin, I'm not aware of any numbers for longwire antennas, but in general IIRC as the antenna "tubing" gets thicker, the antenna can work a wider frequency range with lower SWR.

I'm probably getting something not-quite-right with that description, but for conventional antennas thicker tubing has definite advantages, and the same physics behind it would tend to indicate a thicker wire for wire antennas might also have some real benefit. (Aside from being thick enough to carry power without heat damage.)

Something you might want to check into.
Reply With Quote Quick reply to this message Share with Facebook
  #18  
Old 02-07-2010
Junior Member
 
Join Date: Jun 2000
Location: Seattle
Posts: 22
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
julied is on a distinguished road
Quote:
Originally Posted by Shortman View Post
There is an interesting note on SSB antennas in the current issue of Sail by Gordon West. BoatWorks Ask Sail p.87. References GAM/McKim antennas that don't need an insulated backstay, the use of a whip antenna, or running a GTO-15 cable inside a double braid sheath & hoisting up the mast when you need.
It is not online yet. Just got it in the mail.
G. West says in this note that the Gam/McKim antenna "is a nice alternative for temporary installations". In my mind this translates to "not as good as a typical insulated backstay installation". Any thoughts on why he might use the word 'temporary'.
__________________
Julie D
Kia Ora
Hylas 44
Seattle
Reply With Quote Quick reply to this message Share with Facebook
  #19  
Old 02-07-2010
hellosailor's Avatar
Senior Member
 
Join Date: Apr 2006
Posts: 10,972
Thanks: 3
Thanked 107 Times in 104 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
Julie, I think I have heard Mr. West comment on this antenna before, some years ago. The antenna is nothing new or magical, and Mr. West sometimes says more than what he is saying, or just what he is saying, if you read between the lines.

As I recall it, he said the antenna was very well made, that he had in fact used one, and that's important because no antenna works well if it takes water damage, etc. But he did not make any comment or judgement about comparable performance or price, and to "read" more about that you only need to know basic antenna design theory. He doesn't do Consumer Reports type comparisons.

There's no $400 worth of antenna there, nicely jacketed and insulated and able to be taken down and moved and raised repeatedly and still work as well as it does on day one. Unless you figure, someone has to pay for low volume hand production, distribution, and retail market, as usual.

You could build the equivalent by trimming some wires yourself for a fraction of the cost, or you could probably outperform it with a permanent installation tuned to your preferred frequencies and matched to your rigging. No matter what antenna you use, the rigging that is unique to your boat will uniquely affect performance and make it extremely difficult for any "one size fits all" solution to work as well on any two different boats.

Antennas all share the same physics, anything that works by "magic" or that isn't described in conventional terms by antenna type and theory, probably is all sizzle and no steak.

But, for the folks who don't want to crunch the numbers and solder the wires...sometimes a well-made "average" performer is still the right product. Sometimes "reliable" is worth having.
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Backstay Insulator for SSB trodzen Gear & Maintenance 31 03-25-2011 01:25 PM
SSB backstay antenna length tharris Gear & Maintenance 3 04-15-2003 05:11 AM
High-Frequency Radio Basics Kathy Barron Seamanship Articles 0 10-14-2000 09:00 PM
Choosing and Installing an SSB Radio Sue & Larry Gear and Maintenance Articles 0 09-28-2000 09:00 PM
Choosing and Installing an SSB Radio Sue & Larry Cruising Articles 0 09-28-2000 09:00 PM


All times are GMT -4. The time now is 05:51 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.