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: 7.040 interference  (Read 3617 times)
WM8E
Member

Posts: 15




Ignore
« on: March 24, 2010, 05:56:42 AM »

For over a month I have been hearing "dead" carriers being sent on or very near 7.040. Since that is the freq I use the most it has become very annoying.The carriers last 4 or 5 minutes at a time with short breaks in between. Does anyone have ideas where this interference may be coming from. WM8E/QRP Bill
Logged
AJ4MJ
Member

Posts: 48




Ignore
« Reply #1 on: March 24, 2010, 07:27:09 AM »

From your description, that sounds like WSPR.  They use a fixed 200hz chunk of each band.  The one for 40M goes from 7040.0 to 7040.2.  

More info:http://wsprnet.org/drupal/.  

And an excellent tutorial from someone no longer involoved with WSPR:  http://www.g4ilo.com/wspr.html

73 de AJ4MJ
Logged
N4OI
Member

Posts: 200




Ignore
« Reply #2 on: March 25, 2010, 04:47:31 AM »

If the carriers are not pure tones, they may be PSK digital traffic.  I find PSK to be very loud from around 7035 to 7040 khz.  73 de Ken - N4OI
Logged
KL7AJ
Member

Posts: 329


WWW

Ignore
« Reply #3 on: March 26, 2010, 08:31:34 AM »

I think 7030 is becoming more of the QRP calling freq because of that.

eric
Logged
W8NF
Member

Posts: 53




Ignore
« Reply #4 on: March 30, 2010, 01:35:21 PM »

The carrier isn't quite dead.  It's got a very slow frequency modulation on it of about 6Hz...very hard to hear.  That's WSPR.

There are a few things at work here.

First, 7.040 has not been the QRP watering hole for quite some time, but due to many rock-bound QRP rigs, there's still activity there.  7.030 has been the standard for quite some time.  I cannot even find a reference that still refers to 7.040.

Second, the published 40 meter "dial frequency" for 40 meter WSPR is 7.0386MHz, and when you add the approx 1.5kHz USB audio tone to that, you land very, very close to 7.040MHz.  As long as the WSPR community operates at the recommended "whisper" level of 100 milliwatts, all can be fine.  WSPR and CW can co-habitate on the same frequency and not bother each other.

However, third, many newcomers to WSPR are attempting to use it as a way to "be heard", rather than simply being a well-behaved node on a propagation reporting tool, which is the point of WSPR.  Therefore, they're not only using in excess of 100mW (sometimes grossly), but they're also setting their transmit percentages way too high.  20% is the recommended amount, but some ops are setting as high as 50%.

So...hate to say it, but you just have to buy that 7.030 MHz crystal.  Gentleman's agreement say so, and poor operators are enforcing it further.

73,

Dave W8NF
Logged
AA5TB
Member

Posts: 81


WWW

Ignore
« Reply #5 on: March 31, 2010, 07:44:18 AM »

There are also U.S. WSPR users that are operating in the unattended mode, which is illegal on 40 m in the U.S.  Some are doing it 24/7.

73,
Steve - AA5TB
Logged
VE3GHM
Member

Posts: 1




Ignore
« Reply #6 on: April 28, 2010, 09:26:55 AM »

Although this thread is a little dated I thought I would add my observations.

Of late I have been keeping notes on various bits of noise that I encounter on the various bands. One source that I have come to be able to quickly and easily identify is that from ethernet (DSL modems, hubs, routers etc). Usually sounds like a weak carrier that will often "buzz" from time to time. At home these signals are about S3 or S4 (sometimes a bit less sometimes a bit more depending on band).

On 40 meters I have some of these "network birdies" around 7.040 - same for 20 meters, right around 14.040 and 14.080. And it doesn't have to be coming from your own network. I can turn off all my computers and network devices and I will still have these "network birdies".

Might just be what you are hearing.

cheers, Graham  ve3gtc / ve3ghm
Logged
ZR4LP
Member

Posts: 2


WWW

Ignore
« Reply #7 on: May 07, 2010, 01:39:09 PM »

I am hearing Carrier continously on 7038,6Khz and also a  CW signal   _._.  C all the time .

Any idea who is putting these carriesrs and CW signals on , WSPR is useless in South Africa cos of the deliberate interferance.

Radio is TS-870 DSP and Dipoles at 18 mtrs on top of the mountain.
Logged

ZS6AF
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!