Line-Of-Sight Question
 

Hello,

For the scanner frequencies in general from approx.140 MHz to 1 GHz, is
propagation truly
line-of-site "totally", or is there bending of the signals by some
atmospheric layer possible at various times ?

Any around 156 MHz fm in particular ?

Is there ever any "ducting" ?

Thanks,
B.

Line-Of-Sight Question
 

"Robert11" wrote in message
. ..
Hello,

For the scanner frequencies in general from approx.140 MHz to 1 GHz, is
propagation truly
line-of-site "totally", or is there bending of the signals by some
atmospheric layer possible at various times ?

Any around 156 MHz fm in particular ?

Is there ever any "ducting" ?

Thanks,
B.

yes there is normally some bending and refraction around hills and buildings
so it is not totally line of sight. generally the higher the frequency the
less bending and the better view of the antenna you need. and yes 150mhz
does duct very nicely at times.

Line-Of-Sight Question
 

"Robert11" wrote in message
. ..
Hello,

For the scanner frequencies in general from approx.140 MHz to 1 GHz, is
propagation truly
line-of-site "totally", or is there bending of the signals by some
atmospheric layer possible at various times ?

Any around 156 MHz fm in particular ?

Is there ever any "ducting" ?

Thanks,
B.



Typically you can expect 20% further than calculated line of sight range on
VHF frequencies. Signals grazing over distant hills can also enhance range
somewhat. Higher frequencies will tend to conform more tightly to line of
sight.

Ionospheric disturbances and ducting (usually in the summer months) can lead
to VHF signals being received at ranges of up to a 1,000 miles, sometimes
more.

Mike G0ULI

Line-Of-Sight Question
 

"Robert11" wrote in message
. ..
Hello,

For the scanner frequencies in general from approx.140 MHz to 1 GHz, is
propagation truly
line-of-site "totally", or is there bending of the signals by some
atmospheric layer possible at various times ?

Any around 156 MHz fm in particular ?

Is there ever any "ducting" ?

Thanks,
B.



Suggest you read the articles at URL:
http://ac6v.com/propagation.htm#VHF

73 Lamont

From OP: Line-Of-Sight Question
 

Hi All,

Much thanks for the info.

Lamont's Link suggestion is terrific-just what I need.

Bob

-----------
"Robert11" wrote in message
. ..
Hello,

For the scanner frequencies in general from approx.140 MHz to 1 GHz, is
propagation truly
line-of-site "totally", or is there bending of the signals by some
atmospheric layer possible at various times ?

Any around 156 MHz fm in particular ?

Is there ever any "ducting" ?

Thanks,
B.