[SARC] FW: [TowerTalk] Field Day Interference

[Wayne E Alday]

--Wayne

Wayne E Alday
IT Manager
A+ / Network+
TV Cable Company of Andalusia, Inc

http://www.andycable.com


-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Dennis W0JX
Sent: Thursday, July 03, 2008 9:52 PM
To: towertalk at contesting.com
Subject: [TowerTalk] Field Day Interference

Thanks to Frank, W3LPL, for the great ideas to minimize interstation
interference on Field Day. Our station, NI8G, worked W3AO on at least 2
bands.
 
We did not have the luxury of the large circle. Our three antennas consisted
of an 80 meter dipole fed with open wire, a 40 meter dipole, a twenty meter
ground plane, and a six meter beam. The antennas were within a 200 foot
circle. Our 80 and 40 meter dipoles met his "end to end" criteria.
 
We minimized interference on 40 and 20 with coaxial stubs. Second harmonic
interference was minimized by using a 20 meter,1/4 wave line section at the
output of the 40 meter station, followed with a shorted, 40 meter
quarter-wave stub connected at the input of a Drake MN-2000 tuner. At the
output of the 20 meter station, an open, quarter-wave 40 meter stub was used
to reduce fundamental overload energy. We had no noticeable interference
between these stations, nor did the 80 meter CW station bother the 40 meter
station. A Johnson, 275 watt Matchbox was used on 80 CW, plus the other
bands as needed.
 
We did have a problem when the 20 meter station was operating BPSK. Its
second harmonic created significant interference on 10 CW but we just asked
the BPSK op to stop Cqing when we needed to finish a Q.
 
The biggest surprise was how well the center fed, 80 meter dipole worked,
especially on 10 and 15 meters. It was up high, almost 60 feet at one end
sloping down to about 40 feet at the other. If we could have only one
antenna on Field Day, the open wire fed, 135 foot dipole would be it.
 
73, Dennis W0JX/NI8G 


      
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
 

__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3243 (20080704) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com
 
 

__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3243 (20080704) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com