Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old February 24th 06, 05:32 PM posted to rec.radio.amateur.antenna
Roy Lewallen
 
Posts: n/a
Default Q about balanced feed line

Amos Keag wrote:

YEP!!

An RF Ammeter will do just fine


Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect an RF
ammeter to determine this?

Roy Lewallen, W7EL
  #2   Report Post  
Old February 24th 06, 05:41 PM posted to rec.radio.amateur.antenna
chuck
 
Posts: n/a
Default Q about balanced feed line

Wouldn't the clamp-on type ammeter as discussed previously provide that
information (provided a section of twin lead small enough to fit the
clamp were used?

Chuck

Roy Lewallen wrote:
Amos Keag wrote:


YEP!!

An RF Ammeter will do just fine



Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect an RF
ammeter to determine this?

Roy Lewallen, W7EL

  #3   Report Post  
Old February 24th 06, 09:29 PM posted to rec.radio.amateur.antenna
Roy Lewallen
 
Posts: n/a
Default Q about balanced feed line

Sorry, when I read "RF ammeter", I thought only of the old type which
resembles a panel meter and has two terminals to connect in line with a
single conductor. A clamp-on type would indeed do the job, as we
discussed here not long ago.

Roy Lewallen, W7EL

chuck wrote:
Wouldn't the clamp-on type ammeter as discussed previously provide that
information (provided a section of twin lead small enough to fit the
clamp were used?

Chuck

Roy Lewallen wrote:
Amos Keag wrote:


YEP!!

An RF Ammeter will do just fine



Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect an
RF ammeter to determine this?

Roy Lewallen, W7EL

  #4   Report Post  
Old February 24th 06, 06:11 PM posted to rec.radio.amateur.antenna
Reg Edwards
 
Posts: n/a
Default Q about balanced feed line


"Roy Lewallen" wrote
Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect

an RF
ammeter to determine this?

=====================================

It's unbelievably easy Roy, you just pass both wires together through
a clamp-on ammeter.
----
Reg.


  #5   Report Post  
Old February 24th 06, 11:19 PM posted to rec.radio.amateur.antenna
Larry Benko
 
Posts: n/a
Default Q about balanced feed line

Hi Roy,

I have a couple of RF current meters with freq. response from 10KHz to
100MHZ that are the types used for FCC part 15, DO-160E testing etc. and
have a transfer impedance of 0dB-ohm. They have an opening of about
1.6" dia. and I sqeeze the feedline together (spacing about 1.5")
temporarily and clamp over both conductors for measurement #1 and clamp
over just 1 of the conductors for measurement #2. I read the output of
the current probe with an RF power meter. In my case the current in a
single conductor was approximately 15dB above the differential current
which seemed to be pretty well balanced. Is there anything wrong with
this approach?

Larry Benko, W0QE


Roy Lewallen wrote:
Amos Keag wrote:


YEP!!

An RF Ammeter will do just fine



Balance requires that the currents in the two wires be equal in
magnitude and opposite in phase (or direction). How do you connect an RF
ammeter to determine this?

Roy Lewallen, W7EL



Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Power radiated from feedlines Reg Edwards Antenna 48 September 2nd 05 08:40 PM
SWR - wtf? john d CB 136 July 2nd 05 08:31 PM
SWR - wtf? Roy Lewallen Antenna 110 July 1st 05 05:30 AM
swr question Fred W4JLE Antenna 27 June 1st 05 01:45 AM
Phone line as SW antenna [04-Apr-00] William Mcfadden Shortwave 12 September 5th 03 04:44 AM


All times are GMT +1. The time now is 11:50 AM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017