[aprssig] K6RPT-12 Balloon Track
N5TEV at CompuServe.com
Mon Dec 3 23:28:36 CST 2012
> Thanks for making me revisit that.
>and... Why is Iceland green and Greenland ice...? What's with that?
>73, Steve, K9DCI
No problem. I worked radar systems in the Air Force for 26 years, so
conversations involving RF "distance to horizon" wake me up.
In watching the balloon radio range circle on aprs.fi, I still remember:
Distance to Horizon(Nm) = Sqrt(1.23 x Alt(ft))
And then we used to add refractive index adjustment, which involved using a
sling psychrometer to obtain relative humidity; calling nearest AF Weather
station to get barometric pressure; and charting the values on a table in
the Radar Tech Manual to apply the correct settings to the radar. Old
analog radars, of which a few were still in operation in the 1980s.
And, BTW when I was stationed in Iceland, the locals said that the Vikings
swapped the descriptions (names) of Iceland and Greenland to steer other
would-be settlers away from the Viking's desired location (Iceland). Don't
know if that's a historical legend or not. :-)
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