[Amps] 1:9 un-un for grid driven tetrode

[Rob Atkinson]

On Sun, Oct 24, 2021 at 9:47 AM Peter Voelpel <dj7ww at t-online.de> wrote:
>
> That 1:9 unun and 450 ohm resistor is obviously for use with a high power
> linear tetrode amplifier.

Obviously?  This is a ham.  No telling what a ham will try.

> Passive grid would not work with grid current.
>

I drive a 4-1000 grid with a grid leak bias resistor all the time.
Separate screen v. supply

> Tetrodes requiring a few hundred volts of drive are for instance 4CX10000 or
> 4CX15000 and similar
>

Why would a ham want a tube with 15 KW anode dissipation?

I was perhaps too dismissive of an unun attempt; maybe it works in
some cases, but a typical LC input network can be made to work across
HF without much retuning provided the driver can tolerate some vswr
excursion.

Cordially,
Rob
K5UJ