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: Testing Baluns  (Read 570 times)
VA1PPG
Member

Posts: 3




Ignore
« on: September 25, 2006, 04:58:04 AM »

I am currently running a coax fed windom antenna with a 4:1 balun made by Bux-comm. It does not seem to be working properly as the there seems to be a poor connection somewhere which gives me a fluctuating incoming signal. I have checked the coax and connections to the balun and they seem to be OK. What is the correct way to test the Balun to see if it is connected and working properly? TNX and 73, Pieter VA1PPG
Logged
W8JI
Member

Posts: 9304


WWW

Ignore
« Reply #1 on: September 25, 2006, 05:29:36 AM »

You can terminate the balun in a resistor load and measure VSWR into the balun.

With a Windom, you want a balun that would match about 200-400 ohms and not chnage SWR when you ground either output terminal to the case of the SWR analyzer while watching input SWR. In other words it should be a current balun.

Since your SWR is jumping around, you may not be able to test the balun at low power.
 
73, Tom
Logged
SSB
Member

Posts: 1




Ignore
« Reply #2 on: September 25, 2006, 10:19:41 AM »

There is nothing in a balun to fail.  Wire doesn't just go bad.  You probably have a bad connection inside, loose wire or something.  You need to take it apart to check it.

Alex....
Logged
K0IZ
Member

Posts: 737




Ignore
« Reply #3 on: September 25, 2006, 06:51:00 PM »

One easy check with an ohmmeter is across the coax (center pin to ground).  This should show a near short due to the balun.  If not, or continuity varies, than you have some type of intermittent between the coax connector and (or in) the balun.

The next check you can make, but more difficult, is to connect a 200 ohm resistor (carbon or other non-inductive) across the balun output (disconnecting the antenna, thus more work).  If you have an antenna analyzer this should show 1:1 (200 ohms/4 = 50).  If you don't have an analyzer and can turn down the power (so resistor doesn't burn up), you could use an SWR meter.  This would test out everything from coax connector at rig up to and including balun.

I would suspect some type of intermittent connection, coax connectors?

John
Logged
G8UBJ
Member

Posts: 478


WWW

Ignore
« Reply #4 on: September 26, 2006, 01:08:58 AM »

Hi there,
I have been round this loop on Tower talk,
 
http://www.eham.net/forums/TowerTalk/7541

It threw up some intresting advice and links

73 Rex (G8UBJ)
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!