Topband: Pre-Stew/LBJ in VK6

[Jim Brown]

On 10/25/2023 12:27 AM, Phil Hartwell via Topband wrote:
> It's uncanny how often the various Stew events coincide with poor 
> propagation and/or severe QRN.

I learned a lot from George Wallner, AA7JV, a brilliant engineer and 
veteran of a dozen or so expeditions to rare entities, and for which he 
mounted a very effective Topband presence. At Visalia in 2019 (and a few 
weeks later at Dayton), he observed that the vast majority of their 
Topband QSOs were made on one night of their 2-3 week expedition. On 
that observation, he based his spectacularly great engineering 
achievement of multiplexing CW and FT8 transmitters into a single TX 
antenna, with receive systems for stations operating both modes that 
rejected the other. And this was for TX frequencies separated by 15-20 
kHz, and for CW RX with even less separation! George also did a bunch of 
very innovative antenna designs to help him and his team meet the 
challenges of individual islands they conquered!

George was, of course, right. He is a very bright guy, obviously quite 
analytical, and he figured out what most of missed. That brilliance made 
him a very rich man, on the basis of multiple patents affecting the 
general public -- those I'm aware of are Point of Sale systems -- and 
he's invested his profits in ham radio. Radio In A Box is another of his 
paradigm changing achievements!

One component of Radio In A Box was an new implementation of a concept 
he'd done a decade earlier -- using power amps that ran on DC, run from 
batteries charged by a generator. This allowed generators, and their 
fuel, to be sized for AVERAGE power requirements, not PEAK power 
requirements, meaning SMALLER, LIGHTER generators that could be run in 
"econmode", meaning that FAR less fuel needed to be transported by boat.

3-4 years ago, I recounted all of this stuff to another very bright 
engineer, AG6EE, who emigrated to the US from the Czech Republic 15-20 
years ago, and became a citizen several years ago. Petr, who takes 
pleasure in activating rare grids on 6M and higher bands, both 
terrestrial and EME, took this ball and ran with it in a very big way. 
One of his major targets is CM79, within walking distance of W6JTI, but 
with only a few square miles on land. The rest is in the Pacific, and 
land to the east is a 3,000 ft ridge that peaks a mile or so from the 
water. A very small triangle is on land, in designated Wilderness, so 
gear must be dragged up a 3 mile trail that gains 1,000 ft, drops, and 
regains to get to the grid corner, where operation is practical.

Petr drags a home brew 100Ah, 48V LiFePO4 battery pack up that trail, 
along with custom-built, very light weight antennas, a KX3, and a home 
brew water cooled power amp, where he operates FT8, MS, an EME! For 
other operations he can drive to, he uses a small generator with the 
100Ah 48V battery back buffering it (for all of his applications, 
there's a small DC-DC convertor to run 12V gear).

I'm implementing a commercial variation of a small generator (Yamaha 
2000i) buffered by three 100Ah 48V LiFePO4 battery packs as standby for 
my home in the Santa Cruz Mountains. Neighbor W6GJB did a propane 
conversion on the generator, and for CQP and 7QP county expeditions, we 
run his generator and mine, also propane converted, (without battery 
buffer, so far,) to run two K3/KPA500 stations (mostly on CW).

It's wonderful how much we can learn both from our elders, and from the 
younger guys! In the world of pro audio, where I made my living, we 
complained that the ancients had stolen all of our inventions.

73, Jim K9YC