Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Ladder line and separating it from tower, gutters, etc  (Read 1561 times)
K4IDK
Member

Posts: 38




Ignore
« on: December 03, 2012, 12:48:18 PM »

I'm about to put up an NVIS antenna that is fed with 450 ohm ladder line, but I'm at a loss about how to keep the ladder line away from my tower, where the center support will be, the roof, the gutters and anything else that pops up during the install. 

If anyone has any ideas let me know.  I know that there's got to be a way to do it.
Logged
WB6BYU
Member

Posts: 13239




Ignore
« Reply #1 on: December 03, 2012, 01:20:45 PM »

Back in the days of TV antennas using 300 ohm twinlead, suitable
stand-off insulators were available commercially that snapped on
the side of a mast, screwed into a wall, etc.  They had a plastic
insulator that held the twinlead inside of a screw eye.

Generally you want to avoid running ladder line along a metal
conductor such as a tower leg or rain gutter, but crossing isn't
a problem as long as there is sufficient insulation to prevent an
arc.  A piece of wood or PVC pipe holding the feedline out from
the tower will do the job - 6" to 12" is adequate, preferably with
a slow twist in the line to keep it from fluttering in the wind. 
Various bits of string or plastic plumbing can be pressed into service
as needed - for example, slitting a pipe lengthwise and slipping it
over the lip of a rain gutter.  Vinyl rain gutter / downspout material
may also be useful.
Logged
PA1ZP
Member

Posts: 236




Ignore
« Reply #2 on: December 03, 2012, 01:33:53 PM »

Hi all

I would say the same crossing is no problem but the 450 ohm ladderline running long a mast I would keep it bout 10 times the total with of the line from the mast or conductor.

73 Jos
Logged
NQ3X
Member

Posts: 64




Ignore
« Reply #3 on: December 03, 2012, 01:38:20 PM »

For the tower, I'd use the PVC.  For my installation, I'm using tiki torches.

Seriously.   Grin

I have got to take some pictures of that...

Bob WP2XX
Logged
K4IDK
Member

Posts: 38




Ignore
« Reply #4 on: December 03, 2012, 01:44:51 PM »

So I take it that running it down the length of the tower is a bad thing, even if separated?  I've got to get it down from the roof top tower to the roof and then across a gutter. 
Logged
KD8IIC
Member

Posts: 157




Ignore
« Reply #5 on: December 03, 2012, 11:38:48 PM »

The Wireman has your tower stand-offs. I find 3-4 inches away is plenty. 73
Logged
WB6BYU
Member

Posts: 13239




Ignore
« Reply #6 on: December 04, 2012, 08:58:12 AM »

Quote from: K4IDK
So I take it that running it down the length of the tower is a bad thing, even if separated?  I've got to get it down from the roof top tower to the roof and then across a gutter. 


Running it down the tower is OK if it is separated - you just don't want to tape it to
the tower legs as you would with coax.  Use PVC pipe to space it out from the tower
leg.  (One approach is to take a PVC T connector and slice off the back so it fits
against the tower leg and secure it with hose clamps, then stick the pipe in the
remaining opening that is now horizontal.)

Crossing a gutter shouldn't be a problem with a couple inches of clearance.  Just
don't lay it in the gutter for any distance.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!