George's work on this system is first class engineering, and has
revolutionized TopBand expeditions, allowing simultaneous use of the two
best small signal modes, CW and FT8, by expeditions transmitting high
power. He developed the system so that the expedition wouldn't miss the
one or two "magic" nights during a 2-3 week trip that generated most of
the QSOs.
But that's a minor achievement in comparison to his Radio In A Box, that
greatly reduces the difficulty of activating islands and other locations
with extremely challenging access. Again, engineering at the highest
possible level. He's been field-testing both systems for contests from
his island in C6 for years, and is currently sailing through Oceania on
another field test. Radio in A Box could have turned that recently very
disappointing trip to a very challenging island into a howling success!
George is one of those geniuses who live among us and have done so much
to advance the state of the art. I'd like to start a movement to
nominate him for the greatest award the ARRL and world ham radio has to
offer for technical achievement!
73, Jim K9YC
On 5/23/2023 11:25 PM, GEORGE WALLNER wrote:
I have built, for DXpedition use, a very selective RX front-end for 160
m for simultaneously operating CW and FT8 on shared TX and RX antennas
with 800 feet of separation. The LC filter had 8 dB loss at 1825 kHz and
it was about 10 dB down from that at 1840 kHz (-8dB at 1825 and -18dB at
1840). That is a 10 dB difference, which should be enough to prevent a
good preamp from saturating.
(I also built a XTAL filter that was 40 dB down, but only had a 2.5 kHz
bandwidth -- OK for a DXpedition that can nominate its RX frequency.)
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