[Lowfer] LF: XRS4 and 5 last night

[Dexter McIntyre W4DEX]

Bob Raide wrote:
> Mike;
> First, thanks for great captures of Dex and me.  A look at Hartmut's 
> grabber showed my signal weak or just identifiable with only a couple 
> solid times.  Same with Markus's grabber.  Dex is south of me by at 
> least 300 KM and it is amazing to see his signal over 7000 KM as solid 
> as a rock!  I don't think it would have been that good on 137-but we 
> will never know only over an average of more runs.
> "One for the propagation experts" is an understatement, indeed.

The antenna here was perfectly tuned at mid day when the high 
temperature was about 42F.  The cold front arrived with high winds and 
the temperature fell quickly reaching a low of 7F by sunrise.  This 
morning I found the antenna impedance had changed greatly producing a 
nasty pattern on the scope match traces.  To get the antenna impedance 
back to where it was at midday yesterday I had to remove two makeshift 
windings from the matching transformer I was using.  I'm using the same 
matching transformer on 74 kHz that I use on 137 kHz.  On 74 kHz last 
fall it took two more turns through the cores than I've ever needed for 
137 kHz.   So I just made a few more passes through the cores with the 
loading coil feed wire.

The freezing weather probably has improved my signal on 74 kHz but the 
day before the freeze Hartmut received XRS5 much stronger than last 
fall.   I suspect this is because the oak trees are now bare.  I like my 
trees but it sure would be nice to have an open space under the LF 
antenna top hat wires.

Here's a picture of the trees with leaves under the top hat wires:

https://dl.dropboxusercontent.com/u/15095569/w4dex/LF/trees_under_tophat_summer.jpg

And a picture just now made:

https://dl.dropboxusercontent.com/u/15095569/w4dex/LF/trees_under_tophat_winter.jpg

The top hat wires run over the trees with one connecting to a tower at 
the right side of the metal building on the right.  Another top hat wire 
runs over the trees to a tower located on the right side of the small 
brown building.  The ends of the two top hat wire connect together going 
over more trees.

Dex