Hi Paul,
Am 17.03.2016 19:06, schrieb Paul Nicholson:
Also was inspired by something that Andy posted recently
about PAs powered from rectified mains. Somewhere in the shed
there's a mains isolating transformer and a nice variac.
Same here, all my large PAs are using a H bridge switching at 320V
directly. I can recommend the IRFP460A.
Also my large PA from the VLF kite experiments were from that design.
There is did not use a ferrite transformer. I took an isolated primary
winding on the large coil, you remember.
I've a vague recollection that someone on the list said that
you don't need an NoV for an earth antenna? Can anyone recall?
It's Roger / G3XBM who should know more details.
I could run a wire for a km across the moors and terminate it
in a bog. There's an industrial audio amplifier in the shed
which is good for 4kW. Such a long earth loop would need
quite a high driving voltage. Also in the shed is a big toroidal
transformer, about 20cm diameter by 10cm thick, which might
make a hefty audio transformer if the material is up to it.
Just try it, even if the results could be ppor. It's a big fun, you
know. Remember my earth antenna in the forst :-)
73, Stefan
|
