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: Unusual pulsing signal on 20 meters  (Read 2718 times)
KC6YUW
Member

Posts: 4




Ignore
« on: January 27, 2012, 11:41:27 AM »

Since Dec.30th, I have been hearing an unusual signal at 14.320 MHz. 50 regularly-spaced long pulses, with rather rough audio modulation in two different audio tones. Tones alternate; 37 pulses in one tone, then 37 in the other. I have heard this signal on the West coast of the U.S.. Another ham on the East coast reports hearing it, too. The signal is heard intermittently, usually between 16:00 and 23:30 Universal Time. It is as strong as  S. 7 to S. 9, at times. No identification that I can discern is ever given. Has anyone else heard this signal, and/or have any ideas about its source or identity? 
Logged
KC6YUW
Member

Posts: 4




Ignore
« Reply #1 on: January 29, 2012, 03:18:07 PM »

Heard the unusual signal again today, intermittently, from about 20:35 to 21:30 U.T. Signal strength up to S. 5. Each long pulse could be heard to be broken up into 4 or five very rapid pulses. These were so rapid that their individual nature might be missed. Given normal 20 meter band propagation, the signal is not heard as early in the day as might be expected of a source to the East of my location. Further, it's not heard as late in the day as might be expected of a source to the West.
Logged
KC6YUW
Member

Posts: 4




Ignore
« Reply #2 on: February 22, 2012, 10:33:12 AM »

The pulsating signal on 14.320 MHz continues to be heard; intermittently, as before. It can not always be heard at the same hours, nor can it be heard every day. This obviously makes it difficult for some to take much interest in it, or even for the most patient and persistent observers to gather information on it.  I find that it's now likelier for it to be heard between 23:30 and 01:15 Universal Time, than at the times previously noted. The signal has persisted for over 7 weeks. As more and more routine explanations for the signal are proposed, and then discarded as unworkable, the more mysterious this signal seems.
Logged
WB4LCN
Member

Posts: 133


WWW

Ignore
« Reply #3 on: February 22, 2012, 08:33:12 PM »

Just a guess... It may be some kind of local RFI. I get a pulsing sound when the neighbor runs her new washing machine. I also go a slightly different pulsing from my roommates plasma TV. I bought an ANC-4 (noise cancelling box) and that reduced much of it. That sounds like your problem too.

Also, you may have found CONTACT 2.

dave Wink
Logged

First, make it work, then make it pretty.
Yaesu Rigs: Kenwood TS-480HX, FT-8900R, FTM-350AR (Bluetooth motorcycle mobile), VX-8DR, SB-102 boat anchor (built one as a kid)

Moderate Spock: "Live for a reasonable amount of time and scrape by."
WX7G
Member

Posts: 5920




Ignore
« Reply #4 on: February 23, 2012, 12:01:20 AM »

What is the repetition rate of the pulses?
Logged
WB4LCN
Member

Posts: 133


WWW

Ignore
« Reply #5 on: February 23, 2012, 07:25:58 AM »

Well, the washing machine, while it is tumbling a load, is about 4 or 5 per second. When it stops, the pulsing stops. The plasma TV pulses about once every 3/4 per second, continuously while it's on.

dave Smiley.
Logged

First, make it work, then make it pretty.
Yaesu Rigs: Kenwood TS-480HX, FT-8900R, FTM-350AR (Bluetooth motorcycle mobile), VX-8DR, SB-102 boat anchor (built one as a kid)

Moderate Spock: "Live for a reasonable amount of time and scrape by."
KC6YUW
Member

Posts: 4




Ignore
« Reply #6 on: February 23, 2012, 08:35:02 AM »

The pulsation rate of the signal is about 50 per minute (~ 0.8 Hz). It's audio modulated with about 500 and 1000 Hz sine waves, alternately in blocks of 37 pulses in each tone. The same signal has been heard on the same frequency in California, New England, Minnesota, and The Bahamas. It has never been heard on any other frequency. It fades in and out in just the same way as a distant transmission sometimes does. I found no 'hot spots' where the signal grows stronger, either in my house, yard, or areas nearest neighbors. I assumed it was an unusual signal mode from a non-ham transmitter intruding on 20 meters, but no one has been able to think of any known mode that sounds like this.    
« Last Edit: February 23, 2012, 08:39:52 AM by KC6YUW » Logged
KL3HY
Member

Posts: 117




Ignore
« Reply #7 on: February 29, 2012, 01:14:17 PM »

The fading would seem to be a dead giveaway that it's not local RFI.  The fact that other locations nationwide can pick it up as well would tend to reinforce this, unless those other hams have neighbors with the same washing machine as Dave's neighbor.   Wink

Have you taken a look at one or more of the sites that have samples of various digital and utility signals?  When you mentioned pulsating signal my first thought was OTHR, but that pulse rate would be really low for that.

Ideally, if you have the ability, get a screenshot of the waterfall display from one of the digital mode software packages showing the signal, and also grab a short recording of it.  If you could post those it would probably help quite a bit.

Logged
K6RXD
Member

Posts: 1




Ignore
« Reply #8 on: March 08, 2012, 01:47:31 PM »

I'd be interested in hearing the audio and seeing the spectrum as well.

We really should have a public catalog of all the uncommon signal sources out there. I know, a daunting task Wink


73, JB
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!