Me parece que tienes el cable coaxial acoplándose a la antena y al variar la
longitud cambia la sintonía. Tienes un buen choke o balún?
David
HK1A
EC5KXA
ex-HK1KXA
> From: cx6vm.jorge@adinet.com.uy
> To: towertalk@contesting.com
> Date: Sat, 24 Apr 2010 20:44:09 -0300
> Subject: [TowerTalk] HIGH SWR because of loops between amp and wattimeter
>
> Hello,
>
>
>
> Today I was reading high SWR in my 20 mts yagi.
>
>
>
> 2.5:1 in 14020
>
> 1.9:1 in 14200
>
> 1.7:1 in 14300
>
>
>
> I have the radio connected to the amp, to the wattmeter and to WX0B
> six-pack. In all this runs I have small pieces of 50 ohms coaxial.
>
>
>
> I connected the 20 mts yagi antenna direct to the K3 and the readings in the
> radio were:
>
>
>
> 1.4:1 in 14020
>
> 1.0:1 in 14200
>
> 1.0:1 in 14300
>
>
>
> I know will be some variation when you go through all the runs from radio to
> amp, wattmeter and antennas switch, but not too high that happens in 20 mts.
>
>
>
> I tested all the other bands and SWR is lower when the antenna is connected
> directly, but not too much difference, for example:
>
>
>
> SWR in the
>
> Main setup
>
> (amp, wattmeter, SWR with antenna
>
> Frequency Antenna switch) direct to the K3
>
>
>
> 28030 1.5:1 1.2:1
>
> 28500 1.1:1 1.0:1
>
> 21020 1.5:1 1.3:1
>
> 21200 1.2:1 1.0:1
>
> 21300 1.1:1 1.0:1
>
>
>
> 14020 2.5:1 1.4:1
>
> 14200 1.9:1 1.0:1
>
> 14300 1.7:1 1.0:1
>
>
>
> 7010 1.3:1 1.0:1
>
> 7050 1.7:1 1.3:1
>
> 7100 2.0:1 1.5:1
>
> 3505 1.5:1 1.5:1
>
> 3550 1.2:1 1.2:1
>
> 3600 2.5:1 2.5:1
>
> 1810 1.2:1 1.1:1
>
> 1830 1.7:1 1.6:1
>
> 1850 2.3:1 2.3:1
>
>
>
> So SWR is reasonable higher when connected through the amp, wattmeter and
> antenna switch in all bands, except in 20 mts that there´s a big
> diference!...
>
>
>
> Is not a problem of the sixpack. I connected the 20 mts antenna with the
> same runs of coaxial with a 2 position Daiwa switch and have the same SWR
> that it have when connected to the sixpack.
>
>
>
> Any idea how can I lower the SWR in the 20 mts antenna when connected to the
> antenna switch?
>
>
>
> Thanks,
>
> Jorge
>
> CX6VM
>
>
>
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>
>
>
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