[Lowfer] Re: Last Season for Lowfers?

[David Willmore]

> Yes, it would do that!  I'm actually a little bit envious - I like the
> excessive in radios too...

The nice thing about the LF/VLF region is that power switching semiconductors
are widely available, easy to work with, and *cheap*.  I don't expect to
see too many tube designs for amateur power levels.  I'd even be a bit
suprised to see *new* design using tubes at any power level.

A pair of MOSFETs will be a full legal limit (US/Canada) amp with plenty
of head room--until/unless they up the power limit from the proposed
100W PEP.  Even if it goes up to the 1.5KW allowed elsewhere, that's 
still solidly within the range of common parts.

I'd actually like to see some creativity shown in pairing amp designs with
antenna designs.  For example, semiconductors tend to work better at lower
voltages and higher currents as compared to tubes.  Loop antennas are high
current, low voltage devices.  Sounds like a good pairing?  Pair a tube
amp with a vertical.  Skip a lot of impedence transformation.

For a LF/VLF vertical, you'll need a little metal 'shed' to house the
matching section, anyway, right?  Okay, why not put the amp in there as
well?  Nicely protected by a metal enclosure, and a solid collection of
ground rods.

For a loop, just build the amp into a little metal lump that fits at the
feed point.  Loops are less likely to see large voltage differientials
across them, so lightning protection becomes a MOV across the loop.

Heck, with the simplicity and low cost that such an amp can have, just
build a few and replace them as they blow. ;)  Might be cheaper than
worrying about protecting them.

Thanks goes to Wild Bill A. for thinking along these line with me. ;)

Cheers,
David N0YMV