John,
Your C31XR at 110 ft is very close to 3 WL high (105 ft).
A 3WL high antenna on 10M has a first lobe centered
at 5 degrees (3db points 3 and 8 degrees) and a second
lobe centered at 14.5 degrees (3 dB points 11 and 17
degrees). There is a significant NULL from 8 to 11 degrees.
When 10M is wide open my 40 ft high antenna
(with 3 dB points at 6 and 19 degrees) plays very well.
Most Europeans are using fairly LOW antennas which
concentrate most of their radiated power at higher angles.
An MUF of 50 MHz will support a 20 degree takeoff
angle on 10M. It is highly probable you are working
them on your SECOND lobe from 11 to 17 degrees.
It is not surprising that the 7 elements of your C31XR
provides more gain then the 2 effective elements of your C4.
A 10M beam at 80 ft has a significant NULL from 11 to 16 degrees.
As I have mentioned numerous times, my TH6 at 80 ft
almost never beats my lower antennas. For that reason,
I expect that when 10M is wide open to Europe, most of
the signals are arriving at my QTH at 11 to 16 degress
which can be covered quite nicely with a LOW antenna.
Tom N4KG
On Wed, 17 Oct 2001 JBaumgarte@aol.com writes:
>
> In a message dated 10/17/01 9:46:48 AM Central Daylight Time,
> w8ik@subich.com
> writes:
>
> <<
> Since the original question concerned a move from 50 to 100 feet,
> in my > experience a single 10 Meter antenna at 100 feet is almost
always
> too high to do much good.
> >>
>
> Welllll, I think it also makes a difference where you are. Here in
> Northern
> Minnesota I have a C31XR (7 el on 10) at 110', and a C4 (3 with 2
> drivers on
> 10) at 55'. The high antenna seldom if ever is below the low one on
10.
> Admittedly, it is a killer antenna on 10, one that actually allows
> me, running 1500 watts, to often beat out stations on the east coast
> running 100 watts to a tribander at 30'. :-)
>
> John, N0IJ
> Duluth, MN
>
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