Topband: A wee bit more on power coupling

Robert Brown Robert Brown <bobnm7m@cnw.com>
Thu, 9 May 2002 08:08:10 -0700 (PDT)


On Thu, 9 May 2002, Pete Smith wrote:

> Well then, I guess I share Tom's confusion.  You did state that 
> verticals would be the antennas of choice in NA and EU, based on the 
> amount of insertion loss for a dipole.  It seems reasonable to ask,
> "-24dB compared to what?"  Or asking the question the other way round,
> what would be the insertion loss of a vertical at the same locations?
> 

Pete, 

No, you are confused, indeed.  My remark about verticals was related 
to THEIR low insertion loss to the north.  I made no mention of
dipoles in the original comparisons for verticals in NA and EU. 

In the next section of my remarks, dipoles showed much greater insertion
loss for the northern direction and that suggested of the two, verticals
would be the antenna of choice for DX signals to the north.  

Next, you ask "-24 dB compared to what?"  Permit me to remind you when I
give -24 dB of insertion loss, I am comparing the intensity of signals
coming right from a horizontal dipole with the signals from that dipole
AFTER encountering the steep field lines in the ionosphere.  Insertion
loss or power coupling is a logarthmic comparison, before and after.  The
comparison is with signals from the SAME source and have nothing to do
whatsoever with signals from another source, say a vertical antenna.  OK?

I thought I was perfectly clear in my remarks but I see now that that was
not the case, for reasons beyond my control.  What more can I say to clear
up this confusion?

73,

Bob, NM7M