Reception distance for VOR
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Reception distance for VOR
The formula is
Distance= 1.25×(square root)height of tower
Question: you are at 3800ft, the tower is at 900ft. What is the reception distance?
Two things: first. I have always been taught the formula above. In recent study notes it show 1.23 not 1.25.
Secondly. Sometimes one uses only the aircraft height, sometimes aircraft height and tower height and also the difference in heights
Could someone please clarify for me. I may have missed something.
P.S. sorry about the way the formula was written.
Distance= 1.25×(square root)height of tower
Question: you are at 3800ft, the tower is at 900ft. What is the reception distance?
Two things: first. I have always been taught the formula above. In recent study notes it show 1.23 not 1.25.
Secondly. Sometimes one uses only the aircraft height, sometimes aircraft height and tower height and also the difference in heights
Could someone please clarify for me. I may have missed something.
P.S. sorry about the way the formula was written.
Re: Reception distance for VOR
It's 1.23 sqrt of height. And obviously it's the difference between the AC height and the antenna. If you're flying at 10 000' ASL and the Antenna is at 8000' ASL then your reception distance would be 1.23 sqrt*2000
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Re: Reception distance for VOR
1.25 is for company routes off airway to figure out MEA. Adds a bit of a fudge factor.
Re: Reception distance for VOR
Actually it's not obviously the difference between the AC height and the antenna. It depends on what the terrain between the AC and the antenna looks like.
If the antenna is on a hill, and the terrain in between goes down to sea level, then it's actually 1.23 * sqrt (antenna height) + 1.23 * sqrt (AC height). Putting the antenna high on top a hill doesn't decrease the range but increases it - which is why they do it.
Here's a diagram: And If the terrain between the antenna and the aircraft is higher than the antenna height, then it's less than the 1.23 * sqrt (AC height - antenna height.)
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- ThatArmyGuy
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Re: Reception distance for VOR
There's an error in your diagram.
The Earth is flat.
The Earth is flat.
Re: Reception distance for VOR
I suspect the person who wants to get the right answer in their CPAER test cares.
DId you hear the one about the jurisprudence fetishist? He got off on a technicality.