[Amps] Starting up a NEW Henry amp

[donroden at hiwaay.net]

You gotta draw normal grid current.

W4DNR

On 2023-12-12 3:37 pm, Alek Petkovic via Amps wrote:

> For what it's worth, I have had terrible problems getting the input 
> matching right on several amplifiers using the VNA, yet when using 
> normal drive levels, as reccommended in the user/service manuals, 
> tuning is a breeze. Therefore, I think that there is some truth in the 
> assertion that tuning at low levels does not work properly.
> 
> 73, Alek VK6APK
> 
> On 12/12/2023 7:27 pm, Rob Atkinson wrote: If you try
> to use the internal auto tuner it will not tune properly as it tunes up 
> at low
> power and the input impedance of the amp changes as the power 
> increases. Power level  should not affect the impedance of a load.  If 
> it does,
> then something is wrong.  A part may be heating up and changing value,
> in which case the matching network should be fixed.  You should be
> able to put a vswr analyzer on the amp input and see the R + X for
> some frequency, and those values should hold for whatever drive power
> you use on the same frequency.
> 
> 73
> 
> Rob
> K5UJ
> 
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