At 10:01 PM 2007-12-12, Lee K7TJR wrote, in part:
> If you are looking at reducing stateside signals (why?) from
> the rear of a cardiod antenna such as the 2 element you describe I
> think you should look at selecting the phasing that will best
> reduce the high angle back lobe that occurs on almost all receiving
> antennas. Most all stateside signals arrive at a fairly high angle
> as they are much closer than DX.
Are there any data on the arrival angles of stateside signals on
160m? I'm no propagation expert, but when looking at the numbers
that are shown in W6ELprop on 80m, it looks like paths of 1000 miles
show arrival angles around 15 degrees with a single F-layer
hop. That seems like a fairly low angle to me. Of course, W6EL's
model isn't really suitable for 160m, but it would seem like the path
geometry wouldn't be too different over these distances.
Certainly, interfering stations and thunderstorms within 300 miles,
where the angles are above 45 degrees, are going to experience lower
inverse-square attenuation and could really use some RX antenna
pattern nulls. There are probably other domestic signals that arrive
at high angles after multiple hops, perhaps because they used a low
horizontal TX antenna that favored a high takeoff angle.
73, Terry N6RY
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|