G7IZU RRD Blog


This is page 2. 

Sporadic E propagation, which is caused by the ionization of the ionosphere at around 90-120 km altitude, is most common between the summer months of May and September in the northern hemisphere, and October to March in the southern hemisphere, during daylight. Openings can also occur at other times, day or night. It's also possible for the muf* to rise high enough for F-layer propagation at these frequencies, but this is much more rare. Fuller explanations for the reasons behind these forms of propagation can be found elsewhere on the net, and if you read nothing else, read this document.

*muf = maximum useable frequency

[Es Gallery page 1] [Back to live spectrum page] See bottom of page form more internal links.

 

2006-06-12

Strange intruder on Channel L3? Read on...


 
 


Above are two consecutive one-hour plots of activity from 12 June 2006, 10 to 12 hours UT. 

In each image, the top half is French channel L3, the bottom half is European channel E2. L3's frequency is 60.500 MHz. The L3 transmitter is on 60.500 MHz exactly, and should be the only occupant of this frequency. It is located at Carcassonne, in SW France, at 143° Azimuth and 940 km distance. 

On channel L2 "normal" meteor activity can be seen (short vertical lines). Starting at 10:10 UT, sporadic E can be seen as a the slightly wobbling signal which is slowly descending in frequency. A lower 50 Hz timebase line appears at around 10:18 UT, proving that the signal is not American in origin. Sporadic E on channel E2 kicks in around 10:30 UT. The sporadic E signal on L2 continues to drop in frequency until 11:20 UT, when it suddenly decides to whizz upwards at a rate of knots (manual correction to the transmitter?)

Where is this extra signal on L3 coming from? Carcassonne, according to TV-List, should be the only user on 60.500 MHz. Another French channel is resident at 60.5312 MHz at Besançon/Lomont. Did this drift down? Or could it be a rogue from channel E4 at 62.250 MHz, possibly a badly maintained TX in Africa? The wobbly signal could indicate either a poorly maintained transmitter, or a difficult and long propagation path, or both.

The signal has also appeared on a 09 June, leading me to think that this is a serial drifter....

 

An intermittent sporadic E signal also appeared on 03 June - the first day I started to monitor this frequency, off-frequency by -20 Hz from the nominal 60.500 MHz...

Any information on this signal, or signals, gratefully received at my contact email link (see bottom of the page), and any conclusions will be reported here. Thanks!

Andy [2006-06-12]
 

 
 

 

[Introduction/Site Index]
 [ LIVE Meteor Detection ] [LIVE Radio Propagation Maps] [NLO LIVE]
[Geminids 2010] [Aurigids 2007 Report] [Guide] [Latest Event] [Alerts via Email]
[Aurora Gallery] [Sporadic E Gallery] [CME Gallery] [Meteor Gallery] [Meteor Shower Calendar]
[Links List] [How-to set up a Radio Meteor Obs Station] [G7IZU RRD Blog]

Follow me @g7izu



This website is Copyright © 2004-2013 Andy Smith G7IZU.
Re-use of original graphics, data and alert systems on other websites is expressly forbidden,
unless prior authorization has been obtained from myself.
Email: g7izu (at) television.f9.co.uk
Twitter: @g7izu

 
Comments please to G7IZU