40 Meter local prop theroy question
 

Assuming 2 identically equipped stations operating
mid day on 40m SSB, how far apart would they have
to be to see differences in propagation from a station
say 500 miles away?

Remember - both stations are identical - same rig, same
antenna (Inverted V @ 40'), same local noise levels, same
radiation patterns.

What I'm trying to visualize is the way a given signal hits
a city and whether an instance where station A can hear
better than station B is a problem with station B or simply
propagation patterns of an inbound signal.

Hope that makes sense..... lol!
--
73 de Ken KGØWX - Flying Pigs #-1055
Elecraft K2 #4913

On Thu, 11 Aug 2005 13:05:17 -0500, "Ken Bessler"
wrote:

Assuming 2 identically equipped stations operating
mid day on 40m SSB, how far apart would they have
to be to see differences in propagation from a station
say 500 miles away?

Hi Ken,

If they (A and B) are separated by your local city/town/village, then
the common sense of the broadcast model would suggest that both of you
have an equal shot at it. Otherwise the entire broadcast industry
would have collapsed in the late 20's from lost listenership.

When I put this kind of test to a propagation modeler, and I tighten
the beamwidth of the antenna to 10°, then after the first hop, the
signal covers an area larger than a 70 mile wide county with its
footprint. I don't think your cross-town buddies are going to be left
out in the cold, if all things are as equal as you suggest.

73's
Richard Clark, KB7QHC

Given the problem as you have stated it, get station B to check his coax or
connectors etc. It is remotely possible, but unlikely that propagation would
be the culprit.

I made the assumption you were not is a city that is spread over several
hundred miles.

"Ken Bessler" wrote in message
news:xrMKe.243$ct5.30@fed1read04...
Assuming 2 identically equipped stations operating
mid day on 40m SSB, how far apart would they have
to be to see differences in propagation from a station
say 500 miles away?

Remember - both stations are identical - same rig, same
antenna (Inverted V @ 40'), same local noise levels, same
radiation patterns.

What I'm trying to visualize is the way a given signal hits
a city and whether an instance where station A can hear
better than station B is a problem with station B or simply
propagation patterns of an inbound signal.

Hope that makes sense..... lol!
--
73 de Ken KGØWX - Flying Pigs #-1055
Elecraft K2 #4913

Some of the other responses seem reasonable for average propagation.
However, I wouldn't be surprised to see short-term variations (on the
order of seconds to minutes) up to tens of dB between antennas placed as
close as a wavelength or less, due to multipath propagation. You've
undoubtedly seen this as the "picket fencing" you get when using a
mobile VHF or UHF rig.

Roy Lewallen, W7EL

Ken Bessler wrote:
Assuming 2 identically equipped stations operating
mid day on 40m SSB, how far apart would they have
to be to see differences in propagation from a station
say 500 miles away?

Remember - both stations are identical - same rig, same
antenna (Inverted V @ 40'), same local noise levels, same
radiation patterns.

What I'm trying to visualize is the way a given signal hits
a city and whether an instance where station A can hear
better than station B is a problem with station B or simply
propagation patterns of an inbound signal.

Hope that makes sense..... lol!
--
73 de Ken KGØWX - Flying Pigs #-1055
Elecraft K2 #4913