SWR Calculation

[Richard-6]

Is there any way to make the KPA500 display reflected power?

Cheers,

Richard Kunc ~ W4KBX
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[Bob McGraw - K4TAX]

Not directly that I'm aware.   Personally, I have a Bird 43P on the
output of the amp.  That way I can read the forward power and then
reflected power with a reasonable amount of accuracy.   Then using the
Bird VSWR Nomograph I can accurately determine VSWR.

With 500 watts output then if the reflected value is:

0.6 watts = VSWR 1.07

1.1 watts = VSWR 1.1

2.5 watts = VSWR 1.15

5.0 watts = VSWR 1.22

8.5 watts = VSWR 1.3

15 watts =  VSWR 1.4

28 watts = VSWR 1.6

55 watts = VSWR 2.0

If you have more than that, you need to do some antenna work.

73

Bob, K4TAX


On 1/30/2020 12:58 PM, Richard wrote:

> Is there any way to make the KPA500 display rateflected power?
>
> Cheers,
>
> Richard Kunc ~ W4KBX
> [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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[Jim Brown-10]

On 1/30/2020 6:24 PM, Bob McGraw K4TAX wrote:
> 55 watts = VSWR 2.0
>
> If you have more than that, you need to do some antenna work.

VSWR is NOT an indicator of antenna performance, it's only an indicator
of the match at the point where it's measured. Further, the excess
feedline loss due to VSWR pretty small below about 3:1.

73, Jim K9YC
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