On Sat, 13 Jan 2007 08:14:05 -0500, "Robert11"
wrote:

Hello:

I understand that fm signals in the 150 MHz and higher range propagate
pretty much as line of sight.

But, is this also true for AM signals in this frequency range ?

This is generally true during hours of daylight. Medium wave signals
bounce off the ionosphere after dark thus allowing for long distance
reception.

--
Posted via a free Usenet account from http://www.teranews.com

Tester wrote:

On Sat, 13 Jan 2007 08:14:05 -0500, "Robert11"
wrote:

Hello:

I understand that fm signals in the 150 MHz and higher range propagate
pretty much as line of sight.

But, is this also true for AM signals in this frequency range ?

This is generally true during hours of daylight.

Huh?

Medium wave signals
bounce off the ionosphere after dark thus allowing for long distance
reception.

What the hell does medium wave have to do with the original question?

dxAce
Michigan
USA

Tester wrote:
This is generally true during hours of daylight. Medium wave signals
bounce off the ionosphere after dark thus allowing for long distance
reception.

Medium wave bounces off the ionosphere all the time; but attenuation
in the lower ionosphere keeps it from reaching it, in the daytime.

Higher frequency makes it through, but can be too high to bounce off
the ionosphere except in the daytime.

Hence the MW good at night (no attenuation) and SW good in the daytime
(enhanced ionosphere reflectivity).

A solar Xray flare can enhance attenuation even for SW to the point that
that band dies as well, but is unusual.
--
Ron Hardin


On the internet, nobody knows you're a jerk.