Plotting terrain between two GPS coordinates
Discussion in 'CB Radio Forum' started by rabbiporkchop, Feb 13, 2017.
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CW Spook Light Load Member
Could have been knife-edge diffraction off one of the mountains or even very short Sporadic E.
rabbiporkchop Thanks this. -
It seems to happen on a daily basis.
I like the knife-edge diffraction idea though. -
I also suggested a form of NVIS but they all poo poo'd it.CW Spook Thanks this.
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CW Spook Light Load Member
Well, the range might suggest that, but theory indicates that NVIS effectiveness decreases with frequency above 8Mhz, and that the probability of success at 30Mhz is near zero. The typical CB antenna is designed to produce a low-angle of radiation, rather than the high-angle of NVIS. NVIS works well down at 80 meters though from a fixed station. It's almost impossible to construct a truly effective NVIS antenna for mobile use on 40 or 80.
rabbiporkchop Thanks this. -
Yes that's what they keep saying but because of his location and the geological make up of the area, it is possible that there is something of a vertical bounce happening even with the D layer absorption.
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CW Spook Light Load Member
Could be. After 55 years at this stuff I'm still convinced it's actually all magic anyway. :
rabbiporkchop Thanks this. -
Yeah it is.
You do any 6M work? -
The most reliable frequencies for NVIS communications are between 1.8 MHz and 8 MHz. Above 8 MHz, the probability of success begins to decrease, dropping to near zero at 30 MHz
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CW Spook Light Load Member
No, that's one band I've never used. We had a local TV station on Ch2 in the analog days, so it wasn't worth the risk of messing up the whole neighborhood. I'm primarily a CW DX'er (306 countries confirmed to date) on the HF bands. Was a Morse op in the Navy, thus the screen name.
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