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Aloha,
=20
Recall a while back I found myself unhappy with the losses I found
in my 220 foot run of new LMR400 coax. It is now replaced on the
bands from 80 to 15 meters with 450 ohm "windowed" twin line,
and I have recovered a dB or more, depending upon the band.
I have left the LMR for the TL160, as the loss on 160 meters
was not significant. Here are my MFJ 259B readings, before and
after. The 450 ohm line begins here in the shack at the output
of my 40+ year old EFJohnson kW Matchbox tuner (modified
with series capacitors in the input primary link coil circuit,
per info LB's(W4RNL) web pages), and at the far end of the twin
line is an Amidon high power 4:1 balun. So the new losses=20
include whatever loss exists in the Matchbox and the balun.
=20
7050...was 1.8dB loss....now, 0.4 dB loss,
=20
10109..was 1.9dB loss...now, 0.5 dB loss,
=20
14020..was 2.1dB loss...now, 1.0 dB loss,
=20
21021.was 2.7 dB loss...now, 1.6 dB.
=20
And these losses still do include most of the flexibility switching
I have here in the shack to choose antennas and transceivers.
Note on use of the 259B: as the line must be "open" to=20
measure loss, I first set the Matchbox with the vertical
antenna connected; setting was for 1:1 vswr and X=3D0.
Then unscrew the coax output from the balun which
left the Matchbox, 450 ohm twin line, balun transmission
system circuit open for the cable loss measurement, hope
this is the correct approach, gave readings I liked, anyway,
hi!
=20
So now I have my dipoles and five of the Gladiator monoband
verticals on the Matchbox; and the beam, TL160 and 10
meter monoband Gladiators on the XMatch. The 10 meter
vertical feeds into the shack via a separate short coax line,
as it is just over the shack above the roof.
=20
Not sure if on rcv or xmit I, or anyone else, will know the difference =
in
signal strength, but at least I feel better about this new set up!!
Was not at all pleased with the previous 2+dB of loss on 20
and 15 meters!
=20
Now I must get on with my radial experiments. BTW, we finished up
the month of June with just short of 10 inches of rain here at my QTH;
so far in July we are up to just a bit over 2. Nice to have some dry
days to work out on the antennas.
=20
73, Jim, KH7M
On the Garden Island of Kauai
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<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type><!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 =
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<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>Aloha,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Recall a while back I found myself =
unhappy with=20
the losses I found</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>in my 220 foot run of new =
LMR400 =20
coax. It is now replaced on the</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>bands from 80 to 15 meters with 450 =
ohm=20
"windowed" twin line,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>and I have recovered a dB or =
more, =20
depending upon the band.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>I have left the LMR for the =
TL160, as the=20
loss on 160 meters</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>was not significant. Here are =
my MFJ 259B=20
readings, before and</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>after. The 450 ohm line begins =
here in the=20
shack at the output</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>of my 40+ year old EFJohnson kW =
Matchbox tuner=20
(modified</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>with series capacitors in the input =
primary link=20
coil circuit,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>per info LB's(W4RNL) web =
pages), and at=20
the far end of the twin</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>line is an Amidon high power 4:1 =
balun. So=20
the new losses </FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>include whatever loss exists in the =
Matchbox and=20
the balun.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>7050...was 1.8dB loss....now, =
0.4 dB=20
loss,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>10109..was 1.9dB loss...now, 0.5 dB=20
loss,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>14020..was 2.1dB loss...now, 1.0 dB =
loss,</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>21021.was 2.7 dB loss...now, 1.6 dB.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>And these losses still do include most of the =
flexibility=20
switching</FONT></DIV>
<DIV><FONT size=3D2>I have here in the shack to choose antennas and=20
transceivers.</FONT></DIV>
<DIV><FONT size=3D2>Note on use of the 259B: as the line must be=20
"open" to </FONT></DIV>
<DIV><FONT size=3D2>measure loss, I first set the Matchbox with =
the=20
vertical</FONT></DIV>
<DIV><FONT size=3D2>antenna connected; setting was for 1:1 vswr =
and=20
X=3D0.</FONT></DIV>
<DIV><FONT size=3D2>Then unscrew the coax output from the balun =
which</FONT></DIV>
<DIV><FONT size=3D2>left the Matchbox, 450 ohm twin line, balun=20
transmission</FONT></DIV>
<DIV><FONT size=3D2>system circuit open for the cable loss =
measurement, =20
hope</FONT></DIV>
<DIV><FONT size=3D2>this is the correct approach, gave readings I=20
liked, anyway,</FONT></DIV>
<DIV><FONT size=3D2>hi!</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>So now I have my dipoles and five of the Gladiator=20
monoband</FONT></DIV>
<DIV><FONT size=3D2>verticals on the Matchbox; and the beam, TL160 =
and=20
10</FONT></DIV>
<DIV><FONT size=3D2>meter monoband Gladiators on the XMatch. The 10=20
meter</FONT></DIV>
<DIV><FONT size=3D2>vertical feeds into the shack via a separate short =
coax=20
line,</FONT></DIV>
<DIV><FONT size=3D2>as it is just over the shack above the =
roof.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Not sure if on rcv or xmit I, or anyone else, =
will know=20
the difference in</FONT></DIV>
<DIV><FONT size=3D2>signal strength, but at least I feel better =
about this=20
new set up!!</FONT></DIV>
<DIV><FONT size=3D2>Was not at all pleased with the previous 2+dB of =
loss on=20
20</FONT></DIV>
<DIV><FONT size=3D2>and 15 meters!</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Now I must get on with my radial experiments. =
BTW, =20
we finished up</FONT></DIV>
<DIV><FONT size=3D2>the month of June with just short of 10 inches of =
rain here at=20
my QTH;</FONT></DIV>
<DIV><FONT size=3D2>so far in July we are up to just a bit over 2. =
Nice to=20
have some dry</FONT></DIV>
<DIV><FONT size=3D2>days to work out on the antennas.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>73, Jim, KH7M</FONT></DIV>
<DIV><FONT size=3D2>On the Garden Island of =
Kauai</FONT></DIV></BODY></HTML>
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