[600MRG] Ground wave propagation

[Laurence KL7 L]

Got to say its hugely interesting watching the spectrum analyser levels change on the drive in to Work here in Anchorage and how HUGE of an increase you get within a few hundred to 1000 metres of a salt water path and how quickly as you move away over glacial morraine how quickly that advantage falls away - and how mountains shadows signals so much up here at MW and LF
Propagation over the land masses here involves skirting around/over the mountains, parts land, part sea and the FCC Ground Wave profiles set against conductivity is a bit finger in the air here. Just moving a Mile  or two can produce a 20dB change in Ground wave level on a line of site path to the transmitter site some 50Kms away - Ive never seen a place like it....except Hawaii or Antarctica where very odd things can happen :-)
Thanks for the link Jeremy
Laurence KL7L et al

> From: jeremy at maris.plus.com
> Date: Thu, 13 Aug 2015 00:15:27 +0100
> To: 600mrg at w7ekb.com
> Subject: Re: [600MRG] Ground wave propagation
> CC: N6lf at arrl.net
> 
> Hi Rudy,
> 
> There's an ITU  ground wave propagation program  GRWAVE written in Fortran that I compiled  on Linux  some time ago. I used it  to compare field strength readings from local BC stations with that from our top band antenna, and it seemed to account quite well for the poorer ground wave propagation on 1.8MHz than medium wave. 
> 
> It  was recently referenced in this paper:
> 
> "Sharing and compatibility analysis of possible amateur service stations with fixed, land mobile, and radiolocation services in the frequency band 5 250-5 450 kHz and the aeronautical mobile service in an adjacent band"
> 
> http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-M.2335-2014-PDF-E.pdf
> 
> Unfortunately the link to the program in the paper is broken, but  searching on the ITU site yields this link:
> 
> https://www.itu.int/oth/R0A0400000F/en	
> 
> which has the Fortran source and a Windows executable.
> 
> 73,
> 
> Jeremy  G3XDK /  G4AQG
> 
> 
> 
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