Topband: Polarisation Coupling Loss - a broadcasters perspective

[Tom Rauch]

> While in P29 in the mid 80s and working with the P&T there we shared a
> site with the PNGBC (broadcasting service).  We had a Consultant over
> from the UK looking as to how the PNGBC could improve the coverage. 
> While on a site visit I marvelled at the vertical antenna (190ft) to
> which the Consultant informed me this was half the problem and that
> they could improve the service in the E-W direction if the antenna was
> horizontally polarised.  A improvement of 20dB in an E-W direction was
> mentioned.  N-S would remain much the same!!  

Hi Bob,

Some key elements appear to be missing in all of this.

Were there ever any A-B tests made to confirm the predictions? Can 
you point me to descriptions of those tests?

Is 20dB the maximum possible predicted attenuation, the average, or 
the minimum?  

While I certainly see a difference in favor of my vertical compared 
to a high dipole at most times, it varies considerably with time of 
day. It indeed may be polarization making the slight difference I see 
 (of course in this case it is opposite to the case you cite) or it 
could be wave angle.

I'm trying to sort out how to tell how much is due to what effect, or 
what the expected variation might be with time.73, Tom W8JI
W8JI@contesting.com