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-----Original Message-----
=20
=20
Just got the TH11 up and find out that the VSWR on 17 meters is =
relatively high, about 1.9. BTW, rechecked all measurement 4 times =
while on the ground, so there is no chance for a wrong element length. =
All traps where disassembled and checked for integrity. The Autek =
analyzer calculates a 1.0 VSWR at 17.760 Mhz though. Approximately 10 =
feet above the TH11 is an old Hy-Gain 402BA which is as high as the mast =
will allow. The TT archives say that acceptable spacing is anywhere from =
8 to 14 feet. IMHO, I think the trouble is the 40 interaction causing =
the VSWR to rise.=20
=20
Any thoughts and possible cures, short of a new mast?
=20
73,
Bob, K3GT
=20
=20
=20
You are correct, Bob. I once had a 2 element M2 40 m yagi 10 feet =
above my TH-11,
and it moved both 17 and 15 meters down below each band. The bad =
thing about the
interaction is you do not know what kind of pattern skewing is =
happening on 40 m also.
There is no cure that I know of. I never had enough mast to get the =
problem to go away.
Earlier use of a Mosley 40m dipole above the TH-11 was a success =
because I had the
dipole in line with the boom on the TH-11.
=20
GL!
=20
(((73)))
Phil, K5PC
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5px">
<DIV><FONT face=3DArial size=3D2><B>-----Original=20
Message-----</B><BR><BR></DIV></FONT>
<DIV><FONT color=3D#000000 size=3D2>Just got the TH11 up and find =
out that the=20
VSWR on 17 meters is relatively high, about 1.9. BTW, =
rechecked all=20
measurement 4 times while on the ground, so there is no chance for a =
wrong=20
element length. All traps where disassembled and checked for =
integrity. The=20
Autek analyzer calculates a 1.0 VSWR at 17.760 Mhz though. =
Approximately 10=20
feet above the TH11 is an old Hy-Gain 402BA which is as high as the =
mast=20
will allow. The TT archives say that acceptable spacing is anywhere =
from 8=20
to 14 feet. IMHO, I think the trouble is the 40 interaction causing =
the VSWR=20
to rise. </FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Any thoughts and possible cures, =
short of a=20
new mast?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>73,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Bob, K3GT</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>You are correct, Bob. I once had =
a 2 element=20
M2 40 m yagi 10 feet above my TH-11,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>and it moved both 17 and 15 =
meters down=20
below each band. The bad thing about the</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>interaction is you do not know =
what kind of=20
pattern skewing is happening on 40 m also.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>There is no cure that I know of. =
I never had=20
enough mast to get the problem to go away.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Earlier use of a Mosley 40m =
dipole above the=20
TH-11 was a success because I had the</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>dipole in line with the boom on =
the=20
TH-11.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>GL!</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>(((73)))</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Phil,=20
K5PC<BR></FONT></DIV></BLOCKQUOTE></BODY></HTML>
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