[SEDXC] Working the JA's

[Ed]

David Thompson wrote:
 
I bought a small HF-5B mini beam from a JA/W4 who said he worked JA's
on 15 and 20 CW quite easily.  He had the beam tied to a rope and
fixed on JA at 40 feet.
 
It is the low point of the sunspot cycle but with my beam at 86 feet
JA's are easy on 40 SSB.
 
 My beam is down at 34 feet right now so I used my vertical dipole
(Mor-gain 8040) which is 69 feet long > and found that it took more
patience but you get thru OK.

W7RM had a beam below a high bluff aimed at JA.  It was 200 feet
down.  It was funny to hear the JA's and W7RM was almost unreadable!
 
Dave K4JRB
----------------
OK, Dave has inadvertently pointed out the solution, although I doubt
he realizes it.

HIGHER IS BETTER IS NOT CORRECT!!! With a minor exception on stacked 
yagis. 

Sure, you get low angles of TO, but at the same time, you create
multiple lobes at greater angles, and if you don't already suspect it
ALL those lobes consume power in direct proportion 

An analysis I once did was to print the elevation pattern on 1/16"
plotting paper, and then count every single square in each of the
%^&()*&^%$$## lobes. Taking 1 KW as the input, I had about 250 watts
going into the primary load, the rest in higher angle lobes up to 
60 degrees or so.

Back to Dave and his comment about his 40 @ 86 feet. Bet that works 
out to about .62 wavelengths above ground.

Avoid putting ANY yagi or antenna at multiples of .5 wavelength. The
lobe creased straight up is enormous. Try at .625, .875, 1.125 for 
example.

Another factor is the take off angle by itself. If you consider it
takes X number of reflections from the Ionsphere to reach your desired 
location, you need to put as much power as you can into a lobe which
will give you a minimum of bounces. But, be careful. You have to
take into account the "footprint" at your destination or you may fly
right over it. Does little good if you want to work Eu., and one of
your bounces comes down 100 miles from G land, then reflects back up,
and comes back down 1500 miles later. I once had a 80 meter Delta
loop, which had a TO of about 6 degrees. Absolutely worthless into
Europe, but the middle east was a piece of cake.

One last thing. I have forgotten where I read it, but the author ( who
was a pretty sharp DXer ) stated that in over 90% of the time, signals
from Europe arrive on the East Coast at arrival angles of 20-23
degrees. Now, put that antenna up real high, and see where you get a
60 db null.

73
Ed