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Smooth Earth Diffraction Calc - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

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 Post subject: Smooth Earth Diffraction Calc
Posted: Thu Jan 25, 2007 11:51 am 
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.

 Post subject:
Posted: Mon Mar 05, 2007 11:23 am 
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Joined: Fri Apr 07, 2006 6:10 pm
Posts: 22
I found this interesting article: ... ateurs.pdf

I hope this helps. :-)

 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.

 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