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: Mobile antenna grounding  (Read 390 times)
KC0FGH
Member

Posts: 2




Ignore
« on: April 04, 2002, 12:20:31 AM »

I am mounting a hamstick antenna to a 96 Grand Caravan with a homebrew steel bracket that attaches to the trailer hitch mounting holes of the fram and extends out to a corner of the van.  It is a receiver-style mount in that when not in use I pull a pin and can remove the part of the mount with the antenna quick-disconnect on it (the rest of the mount is then pretty well hidden).  I have a ground wire froma screw on the quick-disconnect portion of the mount to a screw on the receiver portion of the mount.  The receiver portion of the mount is then bolted to the frame of the van.  I have experienced high SWR on bands other than 17m and am wondering if the antenna is too close to the van body or if I may have a grounding problem.  Should the antenna be grounded directly to the frame?  Is that any different than what I already have?
Logged
K8YOY
Member

Posts: 13




Ignore
« Reply #1 on: April 04, 2002, 01:14:39 PM »

I suggest that you run a ground strap from the trailer hitch ground at the antenna mount to somewhere on the body (like in the door jamb or floor of your van area).  Make sure that it is braided strap (not just a wire)and as short as possible for good rf conductivity.  Strip the paint off the point of attachment on the body. You can solder it or mechanically attach it using a sheet metal screw, flat washer and star washer in some configuration that gives you excellent contact. My 25 years of mobile experience tells me that your antenna will love the car body as a counterpoise.  It actually becomes a radiator as well as the antenna!  bye bye SWR problemos!!!!! PS the loading coil of the antenna should always extend above the roof as far as possible.
Logged
K8YOY
Member

Posts: 13




Ignore
« Reply #2 on: April 04, 2002, 01:30:28 PM »

Actually, you would be way better off with a three or four 5" type mag mount on the roof of your car.  No further ground required for forty and above.  Less ground losses.  Omni directional radiation.  Better signal reports that a bumper mount.  An 8 foot antenna on the roof performs equal to a similar 12 foot antenna mounted on the bumper.  Thanks again
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!