I believe something like that is used at SAQ (Grimeton Radio) on 17.2 kHz as a
saturable reactor for keying the transmission.
John F5VLF
> On 18 Apr 2017, at 18:18, DK7FC <[email protected]> wrote:
>
> Hi all,
>
> I'm just thinking about transductors and find them them quite fascinating
> again. I read a bit Wikipedia and thought about the use as a steerable
> transformer.
> Imagine you have a hard switching class D PA, H bridge or so. The output is a
> constant voltage source and it is no problem to connect no load, as long as a
> proper type of low pass filter is used.
> Then imagine a simple 1:1 ferrite transformer, 50 Ohm to 50 Ohm. The
> transformer has a 3rd winding for a DC current (to compensate the AC
> component transformed from the RF windings, 2 cores must be used, which are
> in parallel for the RF and anti-serial for DC).
> Then i can saturate the transformer with the DC so the µr falls down to 1.
> With this arrangement i could build a linear PA out of a switch mode PA, even
> a fast one, which avoids key-clicks, at least in QRSS-3 (you remember the
> mode) or OP32 or even EbNaut on LF?
> Sounds like an interesting experiment at least. The question is how warm the
> transformer would become when the RF output current is permanently reduced to
> 50%.
> Has someone ever tried that on LF/MF?
>
> 73, Stefan
>
[email protected]
Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and ROBSONNE
|
