[Elecraft] K3 SWR Accuracy - reprise

[Steve Ellington]

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
N4LQ at carolina.rr.com
----- Original Message ----- 
From: "Kok Chen" <chen at mac.com>
To: "Elecraft Reflector" <elecraft at mailman.qth.net>
Cc: "Steve Ellington" <n4lq at carolina.rr.com>
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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