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Re: LF: 500KHz QSB

To: <[email protected]>
Subject: Re: LF: 500KHz QSB
From: "Graham" <[email protected]>
Date: Sun, 28 Dec 2008 16:43:20 -0000
Importance: Normal
In-reply-to: <008501c96908$4f961320$6401a8c0@asus>
References: <005a01c968ff$2a99ee10$6401a8c0@asus> <2AE02D153B264F6D83CE8993AEA5F44E@AGB> <008501c96908$4f961320$6401a8c0@asus>
Reply-to: [email protected]
Sender: [email protected]
Gary,
 
Thats about it , the refraction is from a 'media' that's not stable so  you will have differing propagation on adjacent frequency's  
 
One of the reasons these wide band data systems constantly out perform 'simple cw' over long paths , using a sort of frequency diversity
 
G ..
 

Sent: Sunday, December 28, 2008 4:21 PM
Subject: RE: LF: 500KHz QSB

Hi Rik & Graham,

 

Thanks for the replies.

 

All understood now, the screen shot certainly shows it up.

 

I didn?t relate multi path fading to what I was seeing on the display as I am normally used to seeing/hearing single narrow signals  fading differently from different sources. So I hope I am correct in saying that with the three distinct signals from the NDB the additive & subtractive properties of each multi path signal even though closely related in frequency will react so noticeably differently at the receiver even from the same source.

 

I missed Grahams report on the UK500KHZ group.

 

73

 

Gary ? G4WGT.

 


From: owner-[email protected] [mailto:owner-[email protected]] On Behalf Of Graham
Sent: 28 December 2008 15:30
To: [email protected]
Subject: Re: LF: 500KHz QSB

 

Gary,

 

I assume its selective fading , you can see it at 100 Hz separation at >

 

 

add the shot with a few pointers ?

 

G ..

 

Nb ..  check out the 500 band in those day's , no mal-adjusted cw signals

right in the middle !

 

 

 

From: Gary - G4WGT

Sent: Sunday, December 28, 2008 3:15 PM

Subject: LF: 500KHz QSB

 

Hi LF,

 

Just made an interesting observation regarding QSB at 508KHz.

 

For my own benefit I have started running a slow SpecLab showing 500 to 510KHz & capturing for evaluation.

 

Occasionally the NDB ?Z? shows up. The strange thing is that even though the carrier on 508KHz & the two ID offsets at 509 & 507KHz are relatively close they each display at different depth of fading or an out of phase fade pattern.

 

I am unsure why this should be, any comments please, see capture at link :-

 

http://myweb.tiscali.co.uk/wgtaylor/ZNDB.jpg

 

73,

 

Gary - G4WGT - IO83QP.

 



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