I recently built the tube version of the BCS. I used 2" dia tubing up to
the 40m trap then transitioned to 1.5" tubing upt to the 80m trap. I
followed the LC type trap guidelines in ON4UN's book. Both 40 and 80 meters
work well although they resonate a little high, I can easily fix that. The
problem I seem to have is on 160. When i first put the antenna up, I
couldn't get a sharp resonance on 160m. I was expecting 20 to 30 khz or so
of bandwidth. The swr goes from 3.6:1 at 1.78 mhz to 4.6:1 at 1.85 mhz. I
just lowered the antenna removed the trap and checked it again. It has a
nice dip right around 3.51 mhz.
I have the wire inverted L part pulled out almost straight from the top.
Should I lower it to form more of and angle thereby increasing the
capacitance? Has anyone had this type of problem?
BTW I have about 45 radials ranging from 60 to 55'. The R measured at
the
base is right around 11 ohms which seems reasonable. My TS-850 tuner loads
it fine but I think it should work better without the tuner.
Any suggestions?
Tom W3TA
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