LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #23   Report Post  
Old November 28th 07, 05:26 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Oct 2007
Posts: 50
Default Low Noise receiving Loop antenna

Owen Duffy wrote:

Roy Lewallen wrote in
:

Owen Duffy wrote:
. . .
If you try something beside a shielded loop, make sure you use an
effective means of isolating the feed line from the loop so that
pickup on the feedline does not feed the receiver.
. . .


In my limited experience, it's extremely difficult or impossible to do
a good job of isolating the feedline from a small loop. The common
mode impedance is just too high.

Roy Lewallen, W7EL


Hello Roy,

I have a small loop with inexpesive voltage balun, and it gives a quite
deep null (though I can't put dB figures on it off hand), and very sharp
null.

I wonder if the reason that Tony perceives that the nulls are shallow is
that he is assessing it on band noise. If so Tony, you should assess the
depth of the nulls on a local (ie low elevation) point source that is
much stronger than band noise. The test signal should dominate the
receiver.

If an antenna with deep nulls doesn't reduce band noise much, it
suggests that the noise is not mainly from a single direction... as
discussed earlier in this thread.

Owen


the band has been devoid of strong noise the past few days. I think I know
who isn't home in my neighborhood and where the noise may be coming from.
All I need do is have the noise return when she gets home from her trip.

The loop points at her home and the one behind me when the noise is up.
Maybe we got the culprit.

I had recorded an hour and a half of a pileup awhile back and in lstening to
the recording again there was almost no noise. this was 3-4 months ago.
As I had posted previously the noise showed up a little over a month ago.

Oh, one more thing, I will be replacing the coax on the loop over the next
day or so. My gut tells me to try this.

Just because you purchase a new run of coax it doesn't mean it doesn't have
a defect. Its the only thing I haven't looked at.


 
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
Low Noise Receiving antennas Tony Giacometti Antenna 21 October 14th 07 07:18 AM
Receiving Loop John Antenna 5 August 13th 06 06:16 PM
Receiving loop antenna design Owen Antenna 36 June 25th 05 01:34 AM
Random Legth Receiving Only Ant.; Close Into A Loop ? Robert11 Antenna 2 September 26th 04 03:26 AM
Technical question for receiving TV signals by a loop Antenna David Kao Antenna 0 January 20th 04 01:14 AM


All times are GMT +1. The time now is 06:00 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