Topband: A wee bit more on power coupling

Tom Rauch W8JI@contesting.com
Thu, 9 May 2002 23:03:44 -0400


Hi Bob

I asked:

> > Are you saying the signal from a horizontal dipole at my location
> > oriented E-W (broadside N/S) would be 24 dB down due north of me
> > into Ohio or Ontario compared to a vertically polarized signal with
> > the same ERP?

> No, that is not what I said nor meant; there was no mention of a
> vertically polarized signal with the same ERP. 

Then what are you saying? Below it sounds like you are saying the 
coupling would be worse, and so the dipole would have added 
attenuation to the tune of almost 24dB compared to a vertical (you 
said a vertically polarized signal would have very little "coupling 
loss").

> The -24 dB insertion loss or power coupling is the result of a
> horizontally polarized signal from a dipole encountering steep
> geomagnetic field lines. It is the dipole's signal that is attenuated.

OK. That is exactly what I asked. The dipole is attenuated a large 
amount, the vertical is not significantly attenuated. That means with 
the same ERP from both a vertical and dipole antenna, the signal from 
a dipole should be significantly attenuated. 

If it does not mean that, then exactly what are you saying?73, Tom 
W8JI
W8JI@contesting.com