Smooth Earth Diffraction Calc - RF Cafe Forums

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nubbage
 Post subject: Smooth Earth Diffraction Calc
Posted: Thu Jan 25, 2007 11:51 am 
 
General
User avatar

Joined: Fri Feb 17, 2006 12:07 pm
Posts: 304
Location: London UK
Hi Yorl
I have a trivial problem to solve but no budget for suitable software.
Anyone know a reliable freeware or website with a Java applet to compute smooth earth diffraction at VHF?
I am trying to predict performance of a system using yagi antennas at 160MHz over an 80km smooth path using -110 dBm sensitivity receivers and 45watts Tx power with 8 or 10dB gain antennas each end, low feeder loss.

"Anyone, anyone?"
And for 5 bonus points, where does that quote come from?

The usual undying devotion to those who can help.
 
   
 
Mr.Whatever
 Post subject:
Posted: Mon Mar 05, 2007 11:23 am 
 
Captain
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Joined: Fri Apr 07, 2006 6:10 pm
Posts: 22
I found this interesting article:
http://www.nor.com.au/community/sarc/re ... ateurs.pdf

I hope this helps. :-)
 
   
 
nubbage
 Post subject:
Posted: Tue Mar 06, 2007 6:01 am 
 
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Joined: Fri Feb 17, 2006 12:07 pm
Posts: 304
Location: London UK
Hi Whatever
Thanks a bunch for that link. As the author says "Information on the subject is very hard to come by."
I will follow up one of the references he mentions.
I had not seen this approach to analysis. It does not appear to be either ITU-R or NBS, and the author of the paper admits he has lost the provenance of the procedure.
Thanks again. It will give me a third approach, and hopefully narrow down the discrepancy I am experiencing when using different methods.
 
   
 
Mr.Whatever
 Post subject:
Posted: Wed Mar 07, 2007 5:22 pm 
 
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Joined: Fri Apr 07, 2006 6:10 pm
Posts: 22
Hi nubbage :)

If you send me an email at mr[dot]whatever[at]gmail[dot]com, I can try forwarding you a PDF file that I got. I'm not sure if it helps, but its worth a try.

Replace [dot] with . and [at] with @ in the email.




Posted  11/12/2012