[Amps] Switch-mode HV power supply
Ian White, G3SEK
G3SEK at ifwtech.co.uk
Fri Mar 12 08:24:38 EST 2004
>
>Does anyone recall the URL for the switch-mode HV power supply that was
>featured in QST New Product some months ago?
>
>Has anyone tried it?
>
Thanks to everyone who replied: it's http://wattsunlimited.com
The reason for this inquiry is that I'm preparing a talk on power amps
for the GM DX Convention. They have asked me to include some comments
about "tubes v transistors" with a focus on DXing, contesting and
DXpeditions. Comparing cost, size, weight and reliability for the two
different technologies, an interesting question pops up: are our
existing tube amps as small and lightweight as they could be?
The answer seems to be "no, not yet". We really haven't explored the
possibilities of SMPS instead of heavy iron... and we haven't even fully
explored the potential of compact, lightweight mains transformers.
G3WOS's website has a very interesting project description of an 8877
DXpedition amp for 6m, that fits into an airline pilot's flight case and
weighs in at just 40 lb - for the complete amp and power supply!
(Compare this with 70 lb for an Acom 1000, which most people would
regard as a reasonable size and weight for a 1kW desktop amp.)
http://www.gare.co.uk/amplifier/dxpedition_amplifier_overview.htm
G3WOS uses a custom transformer with a strip-wound core, from Heritage
Magnetics in the USA - plus a *lot* of detailed attention to making all
the parts fit into the box without wasted space. Admittedly this is a
monoband amplifier, and the output circuits for an all-band HF amp would
need more space... but it does show there is more that could yet be done
with the "old technology".
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek
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