[Elecraft] Four Band K1 and antenna (Test Session) [Long]
Ron Polityka
[email protected]
Sat Jun 29 20:02:03 2002
Hello,
About a month ago I posted an e-mail about a doublet type antenna and a
Elecraft K1 four band radio with built in tuner. The bands that I have are
40, 30, 20 & 15 meters. I was using 350 ohm mini-ladder line and I had
problems tuning certain bands. Well today I had an opportunity to do some
extensive testing. Thanks to Len, N2BSC, I had a place to do a four hour
testing session.
I was looking to use my 66' doublet with a short transmission line for use
on the Appalachian Trail. Well to my surprise I have found a good usable
length. The average height that the antenna usually is when out on the trail
is around 12' to 14' up in the air. Here are the results of my test.
I did not have a 25' length of 350 ohm mini-ladder line to use but I did
test one length of what I had made up.
Antenna Height: 12'6" @ center
Distance away from center of antenna: 18'
I used the 350 ohm mini-ladder line 15' in length connected directly to the
back of the K1 with a BNC to Binding Post connector. The SWR's were high and
the internal tuner was working hard. It did not achieve a low SWR to my
satisfaction, 1.5 to 1 or lower. This was with a 4 to 1 balun and with out
one connected.
The following test were with 300 ohm twin lead connect to the K1 directly
with the BNC to Binding Post connector and no balun.
Length
of 300
twin lead 25 ' 24' 23' 22'
7.040 1.1 to 1 1 to 1 1 to 1 1 to 1
10.106 1 to 1 1.1 to 1 1 to 1 1.1 to 1
14.060 1.2 to 1 1 to 1 1 to 1 1.1 to 1
21.060 1.1 to 1 1 to 1 1.1 to 1 1 to 1
Length
of 300
twin lead 21 ' 20'
7.040 1.1 to 1 1 to 1
10.106 1.1 to 1 1 to 1
14.060 1.2 to 1 1 to 1
21.060 1 to 1 1 to 1
Length
of 300
twin lead & 30" of RG174 & 30" RG8
7.040 1.1 to 1 1.1 to 1
10.106 1 to 1 1 to 1
14.060 1.7 to 1 1 to 1
21.060 1.3 to 1 1.2 to 1
Length
of 300
twin lead & 30" of RG8X & 25' of RG8X turned
into a 6" wide 10
turn balun
7.040 1.1 to 1 8.1 to 1
10.106 1 to 1 1 to 1
14.060 1 to 1 1 to 1
21.060 1.2 to 1 1.3 to 1
Length
of 300
twin lead with 4 to 1 balun with 4 to 1 balun
and 30" of RG8
7.040 1.1 to 1 1.1 to 1
10.106 3.9 to 1 3 to 1
14.060 1 to 1 1 to 1
21.060 1.3 to 1 1.1 to 1
Length
of 300
twin lead with 4 to 1 balun
and 29" of RG8
7.040 1 to 1
10.106 1 to 1
14.060 1 to 1
21.060 1.3 to 1
The reason for the short length of RG8 or RG8X is to bring the antenna
inside the tent when camping. If anything is close to the twin lead, the SWR
does rise.
So it looks like I will be using the 20 feet of 300 ohm twin lead to the
back of the rig when I go out hiking on the AT. But when I do some camping I
will take along the RG8X. All test were performed with the antenna at the
same height.
72 & Good DXing
Ron Polityka
de WB3AAL
[email protected]
vvv Eastern Pennsylvania QRP Web Page vvv
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