Posted by
Steve Ellington on
Nov 05, 2009; 1:05am
URL: http://elecraft.85.s1.nabble.com/K3-SWR-Accuracy-reprise-tp3943810p3949471.html
Nope:
The 1/4 wave line transforms the high impedance to a low one and the SWR
meter reads low. It's called a transmission line transformer and is very
common. It's the reason everyone is having trouble understanding why SWR
meters read differently. The ONLY way to compare them is to swap them with
each other. Putting them in series fouls up the readings for both meters.
Steve
N4LQ
[hidden email]
----- Original Message -----
From: "Kok Chen" <
[hidden email]>
To: "Elecraft Reflector" <
[hidden email]>
Cc: "Steve Ellington" <
[hidden email]>
Sent: Wednesday, November 04, 2009 7:55 PM
Subject: Re: [Elecraft] K3 SWR Accuracy - reprise
>
> On Nov 4, 2009, at 4:41 PM, Steve Ellington wrote:
>
>> 4. Example: A full wave dipole center fed with 50 ohm coax. SWR reads
>> infinite at the antenna but with 1/4 wavelenth of coax, SWR reads low!
>
> Nope -- the *impedance* at the end of a 1/4 wave transmission line
> when it is looking at a very large impedance, is close to zero,
> therefore the SWR remains close to infinite. The SWR definitely won't
> read low unless there is something wrong with the instrument.
>
> 73
> Chen, W7AY
>
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