[K3PZN-List] FD2008 Advanced Planning

[James Owen]

Hi Curt and Gang,
   Let me add a little here, even though I wasn't with
you guys, our group had severe interference also,
mainly on 40M.
   Guys this is not rocket science. (apologies to John
W3JJH) The NIST club mostly solved this problem 20
years ago.
   The main solution is antenna separation. Any
antenna should be at least 200-250 feet from the next
nearest antenna more is better. This will cure about
75% of the problem. With the 1000ft circle this is
easy to do if you have that big an area.  Like band
antenna's, 40 CW, 40 Phone, 40 PSK31 should be at
different sides of the 1000' circle, ie 400ft or more
away from each other minimum, more is better. 
   You will find that the biggest problem is on 40
meters.  There will be some problem with 2nd harmonic
of 75M  cw on 40M phone and 40M CW/PSK31 2nd harmonic
on 20M but these can be reduced and usually only
effect about 10 Khz or less on the receiving end.
  Put up no antenna parallel to another unless it's at
least the 250ft distance as above, especially same
band.
 Other ways to get small increases in interference
reduction. Use only resonate antenna's--as they will
be an inefficient radiator of the 2nd harmonic and
other wide-band interference.  Use no multiband
antenna's for the same reason (tri-banders, trap
dipoles etc) as they are more efficient at radiation
of 2nd & 3rd harmonics.
  A good  tuner especially a high C output will add
2nd and 3rd harmonic rejection, maybe as much as 10db.
  Use equipment that has good harmonic rejection and
low phase noise output. I will step on some toes here
I'm sure. I have found over the years that the
transceivers that generally cause more interference
especially phase noise are ICOM's. The IC-706 is very
bad. Some Yaesu's are also pretty noisy. In general
the best are the older Kenwoods's TS-820s/830s and the
Yaesu FT-1000 are not too bad. Most of the Ten-Tec's
are great as are the Elecraft K2's. You can look at
the ARRL test results to determine which to use. Try
to chose one that the wide band phase noise  under
-110db and the 3rd order IMD is better than -25db.
Chose a rig for CW that has a slow rise time of at
least 5ms-6ms. The Yaesu has been very bad on CW for
years and cause bad key clicks with a rise time on the
order of 1ms. ICOM is not much better but a little.
Kenwood's seem generally to be ok and it seems all
Ten-Tec's and K2 are just fine.
   Be sure that everyone follows the planning. In past
years I have used the 40M location that was planned.
At the last minute someone showed up to do
packet/PSK31 and said this looks like a good place to
set up and put the 40m packet antenna 10-20' from the
40M phone/CW antenna. And yes it happened again this
year. When packet/PSK is transmitting 40 phone is
dead. The IC-706 had so much garbage it covered the
40M band with 20+ db over S9 noise and even when the
data stream quit and before the carrier dropped there
was still an S6 noise level, this is phase noise. I
know I lost at least 100  contacts on  phone/CW where
PSK picked up about 60. Big question is, if this
always happens is it worth running PSK if you're
trying to get the biggest score?

   I'll stop now. Biggest improvement will be to
separate antenna's, chose best equipment and keep the
packet/psk station as far away as possible.

73 Jim K4CGY


James C. Owen, III K4CGY


       
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