Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 30-09-2009, 18:42   #1
Senior Cruiser
 
roverhi's Avatar

Cruisers Forum Supporter

Join Date: Aug 2005
Location: Kona, Hawaii, Carlsbad, CA
Boat: 1969 Pearson 35 #108 & 1976 Sabre 28
Posts: 6,002
Send a message via Yahoo to roverhi
Ground Plane Tape for HF Radio

I'm running 3" wide copper tape under the deck near the rail on both sides for the HF radio ground plane. There is a lot of through deck fasteners along the way, some in the way of the tape run. Does it hurt the effectiveness of the tape as a ground plane if I fold the tape in 1/2 to get around a few of these fastenes/backing plates?? Probably not more than 5 or 6 areas for a length of 3" or so each to fit around fasteners and backing plates.

Assume I need to insulate any fasteners that may come in contact with the tape. These fasteners are for ungrounded deck hardware like lifeline stanchions and blocks, btw.

Where the copper tape is freehanging, intend to glue it in place with 5200.

The Icom AH-4 tuner is mounted on the stbd side on the lazarette bulkhead. Planned on making a right angle turn at the lazerette bulkhead to go from port side to the tuner on the stbd, a distance of maybe 4' Seem to remember that the tape is supposed to run as straight as possible. Can do away with the right angle turn at the bulkhead by running the tape diagonally under the cockpit with about a 30-40 degree bend in the tape at the galley bulkhead if it would be better. Won't be easy running or supporting the tape under the cockpit sole, however.
__________________

__________________
roverhi is offline   Reply With Quote
Old 30-09-2009, 18:57   #2
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2006
Location: Chesapeake Region and Maine
Boat: 42' Bob Perry sloop
Posts: 4,038
Images: 4
Don't worry about the thru-deck fasteners. Punch a hole in the foil. Whether they contact or not is immaterial to the function of the counterpoise.

That said, have you done the first and easy thing first: connected the foil from the tuner to the nearest bronze thru-hull, which is not otherwise bonded? Often, that's quite enough.

You can also use radial wires (insulated wire of any type). You needn't necessarily use foil, despite the garbage advice which is often found in user manuals and SSB books about not using wire. That is pure nonsense, demonstrably so.

To make wire radials most effective, use 1/4-wavelength at desired frequency bands (234/freq in mHz = wire length in feet). You can also use untuned radials. More shorter ones are better than fewer longer ones.

Bill
__________________

__________________
btrayfors is offline   Reply With Quote
Old 30-09-2009, 22:56   #3
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Well Bill, your argument that wire is as good as foil is nonsense, not the advise from manufacturers and books to use foil. So, if you care to stand by your statement, you better defend it with reasoning and technical explanation ;-)

The skin effect of RF power traveling through conductors is what makes surface area important.

I just finished redoing the foil aboard Jedi as at some places it was half gone after 6 years. I now made it part of the hull by epoxying it into the bilge and painting it. I can only advise you to do that now so you'll save yourself redoing it later.
I used that G/5 (5-minute) epoxy from West System and BilgeKote for painting it.

The attached photo shows the result of the part where it connects to the copper mesh that is part of the laminated hull (the foil only connects the tuner to that mesh). The green stuff is the oxidation of the old foil that was half gone here.

cheers,
Nick.
Attached Thumbnails
Click image for larger version

Name:	IMG_1612.JPG
Views:	213
Size:	50.7 KB
ID:	10245  
__________________
s/v Jedi is offline   Reply With Quote
Old 01-10-2009, 02:03   #4
Registered User
 
richardhula's Avatar

Join Date: Nov 2008
Location: UK
Boat: S M Hudson 60' narrowboat
Posts: 347
Send a message via Skype™ to richardhula
The foil (& it needs to be foil) should be run along the bottom inside of the hull so that a capacitive connection to the sea can be made.

Whatever people say I have foil running directly from tuner to radio picking up on ground plate, through hulls & main anode along the way. It works great. Regularly used to get Sailmail connection to Lunenburg in Canada (3000+nm) from Tunisia.
__________________
Richard

If in doubt RTFM
richardhula is offline   Reply With Quote
Old 01-10-2009, 04:35   #5
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,571
Images: 240
Would someone describe (or picture) the method of folding foil/tape at corners for a change in direction?
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 01-10-2009, 06:04   #6
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2006
Location: Chesapeake Region and Maine
Boat: 42' Bob Perry sloop
Posts: 4,038
Images: 4
Jedi and Richard,

Sorry, guys, but you're both mistaken. Ever hear of wire radials? Elevated ground planes?

What do you think a dipole is? Mount it vertically on a sailboat, and you've got the most effective antenna you can put on a crusing sailboat (single-band only, though). All wire, no separate ground plane, no physical or "capacitive" connection to the water.

I do this for a living these days, and have decades of experience mounting antennas on sailboats. And testing them against other types of installations. The foil-only argument is pure, unmitigated C R A P.

Foil is fine to use for certain situations, e.g., just running a short length to the nearest thru-hull a la Gordon West. But the famous "100sq ft of copper" is pure bunk.

Wire radials work very well. So, too, do aluminum toerails, s/s rubrails, long metal deck-to-hull joiners, big radar arches, and any number of other solutions for an RF ground.

Bill
WA6CCA
__________________
btrayfors is offline   Reply With Quote
Old 01-10-2009, 06:14   #7
Registered User
 
richardhula's Avatar

Join Date: Nov 2008
Location: UK
Boat: S M Hudson 60' narrowboat
Posts: 347
Send a message via Skype™ to richardhula
Quote:
Originally Posted by btrayfors View Post
Jedi and Richard,

Sorry, guys, but you're both mistaken. Ever hear of wire radials? Elevated ground planes?
Yes I have but my suggestions are based on fact i.e. it's the way most people do it, it works very well on a range of frequencies in conjunction with a back stay antenna, it's easy to do etc.

Remember there is more than one way to crack a walnut.

Mistaken is not the word you should be using. If your in the trade you should know better
__________________
Richard

If in doubt RTFM
richardhula is offline   Reply With Quote
Old 01-10-2009, 06:20   #8
Registered User
 
richardhula's Avatar

Join Date: Nov 2008
Location: UK
Boat: S M Hudson 60' narrowboat
Posts: 347
Send a message via Skype™ to richardhula
Quote:
Originally Posted by GordMay View Post
Would someone describe (or picture) the method of folding foil/tape at corners for a change in direction?
I have a feeling this is a catch question
__________________
Richard

If in doubt RTFM
richardhula is offline   Reply With Quote
Old 01-10-2009, 06:42   #9
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,571
Images: 240
Not a trick (catch) question; just a “tricky” procedure to describe - let me try:

To make a square corner at a 90 horizontal bend in a ground foil:
Bend the foil over at 90 degrees, leaving a biassed corner edge.
Then, bend the bent section back over on itself, now leaving a square corner edge.

I’m not satisfied that describes it adequately, hence the earlier plea.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 01-10-2009, 07:47   #10
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2006
Location: Chesapeake Region and Maine
Boat: 42' Bob Perry sloop
Posts: 4,038
Images: 4
Quote:
Originally Posted by richardhula View Post
Yes I have but my suggestions are based on fact i.e. it's the way most people do it, it works very well on a range of frequencies in conjunction with a back stay antenna, it's easy to do etc.

Remember there is more than one way to crack a walnut.

Mistaken is not the word you should be using. If your in the trade you should know better
Richard...

Perhaps I wasn't making myself clear.

What is mistaken is the belief that RF grounds must be built only with foil, and that wires won't work. Also, that radials must be "capacitively coupled to seawater".

Both of these notions are Wrong. Mistaken. Erroneous. Ill Founded. Disproven. Incorrect.

Sadly, they are too often repeated by people who should know better, as well as other "believers" who shouldn't and don't.

I'm not anti-foil. I use it in installs where it makes sense. But, as you say, there are many ways to "crack a walnut", and foil is just one of them.

Bill
__________________
btrayfors is offline   Reply With Quote
Old 01-10-2009, 08:03   #11
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,327
Quote:
Originally Posted by GordMay View Post
Would someone describe (or picture) the method of folding foil/tape at corners for a change in direction?
Quote:
Originally Posted by GordMay View Post
Not a trick (catch) question; just a “tricky” procedure to describe - let me try:

To make a square corner at a 90 horizontal bend in a ground foil:
Bend the foil over at 90 degrees, leaving a biassed corner edge.
Then, bend the bent section back over on itself, now leaving a square corner edge.

I’m not satisfied that describes it adequately, hence the earlier plea.
Pardon my ignorance but does it matter?

I have always just bent it or folded as required to change direction. As we are only talking HF frequencies a piece of wet string will ALMOST suffice - OK it won't work that well but I have seen so many many poor HF installations that work some of the time, that I truly believe we worry too much at times about getting perfect.

Sure some people should worry more and do more to get it right but if one follows the general recommendations of manufacturers and professionals like say Bill, and then just do the best they can with what they have, the HF will work.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is online now   Reply With Quote
Old 01-10-2009, 09:29   #12
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,571
Images: 240
Here’s some different takes on the subject:

Gordon West ➥ http://www.kp44.org/ftp/GroundingCou...stChapter8.pdf

Icom ➥ http://www.icomcanada.com/techbullet..._grounding.pdf

Dr. John Gregory ➥ Installation Procedure
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 01-10-2009, 09:37   #13
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Quote:
Originally Posted by btrayfors View Post
Sorry, guys, but you're both mistaken. Ever hear of wire radials? Elevated ground planes?
Wire radials are buried into the soil. If you bury foil it'll be gone before you close the trench it is in.

Elevated ground planes: same thing, copper foil won't work because it'll just hang down, break off etc.

The foil doesn't have the physical strength characteristics needed for those applications.

Quote:
What do you think a dipole is? Mount it vertically on a sailboat, and you've got the most effective antenna you can put on a crusing sailboat (single-band only, though). All wire, no separate ground plane, no physical or "capacitive" connection to the water.
A dipole isn't a ground plane antenna so it's mode of operation is different. The section connected to the tuner-ground is called the "passive" side or whatever the correct English term is; it isn't the antenna ground. And again, foil doesn't have the physical characteristics required plus it would create a directional radiation pattern.

Quote:
The foil-only argument is pure, unmitigated C R A P.
I agree with that. But the argument that foil works better (skin effect) is a correct one.

Quote:
But the famous "100sq ft of copper" is pure bunk.
In real world situations on boats, I agree. But when you make a (capacitive or not) connection to the sea water, you actually take a big chunk off that 100 sq ft figure. Same if you connect metal parts like toerails etc. You replace copper with those metal items and/or sea water. I think the 100 sq ft guideline is a theoretical one and replacing copper surface with existing metal parts and coupling with seawater should be included in that same section of the manual or book.

So, use foil where you can to make RF ground connections because it works better than wire. Protect the foil against the environment or it won't last. I would rather fold the foil for a couple of inches to pass a fastener that's in the way instead of punching holes. When you fold, you increase the RF resistance but only for that short section. The big reason for folding is to protect the foil and have clear access to fasteners.

At shortwave frequencies, the implementation is all relatively easy and forgiving. The higher the frequency the bigger the penalty when something is off. For a shortwave install on a boat, it's the lowest frequency used that is the hardest to do right because of the big lengths required on a relatively small vessel.

ciao!
Nick.
__________________
s/v Jedi is offline   Reply With Quote
Old 01-10-2009, 15:26   #14
Registered User

Join Date: Apr 2007
Posts: 718
It's interesting to note that Icom's instruction manual on grounding and antenna considerations states; "Now here’s another very important point, no round wires for RF ground!" and yet inside their tuner's the connection from the ground stud to the circuit board ground plane is a 4" piece of 16 gauge round wire.

The problem with all this is that it is difficult to prove what works best. Just being able to make a contact with a station hundreds or thousands of miles away is NOT an indication of your antenna systems efficiency. I have a very inefficent antenna system on my trailblazer (auto-tuner with 8' whip on back bumper) and make these contacts all the time. I made a contact with a New Zealand station early this morning on the 40 meter ham band from Maryland on a boat on the hard with nothing but 12' of GTO-15 coiled up on the deck for an antenna. The one area where you may see a difference with one ground plane system over another is with how your transmission affects your other onboard electrical/electronics system with interference.

Eric
__________________
fairbank56 is offline   Reply With Quote
Old 01-10-2009, 16:01   #15
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,571
Images: 240
Quote:
Originally Posted by fairbank56 View Post
It's interesting to note that Icom's instruction manual on grounding and antenna considerations states; "Now here’s another very important point, no round wires for RF ground!" and yet inside their tuner's the connection from the ground stud to the circuit board ground plane is a 4" piece of 16 gauge round wire...
Interesting incongruity.
Reminds me of the Xantrex manual that contained a wire length to size chart, requiring cables roughly twice the size of the permanent equipment lugs.
__________________

__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Reply

Tags
hf radio, radio

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Length of Copper Straps for Ground Plane roverhi Marine Electronics 22 23-05-2010 17:05
Cavitation at Plane michaelmrc Auxiliary Equipment & Dinghy 8 22-04-2009 16:46
SSB - where can my ground plane be? esper General Sailing Forum 1 25-03-2009 10:25
Fossett's Plane Wreckage Found Ex-Calif Off Topic Forum 14 07-10-2008 06:05
XM Radio & Sirius Radio cchris0411 Fishing, Recreation & Fun 25 13-03-2007 02:10



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:48.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.