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Registered Member #599
Joined: Thu Mar 22 2007, 07:40PM
Location: Northern Finland, Rovaniemi
Posts: 624
Backyard Skunkworks wrote ...
What the heck kinda power supply do you use for a coil that size? A polepig?
Its not that hard to make or get ~10kVA @ 10-15kV transformer or transformer stack. Maybe pole transformer or few PTs in parallel
Pole transformers are kind of problematic where i live, 3ph power goes everywhere and we have usually quite big step down transformers (100-500kVA 20kV 3~ -> 400V 3~) feeding many apartments at once. Although it is possible to find something smaller like 10kVA but they are rare
I looked one 100kVA unit from junkyard and it was over 250kg :)
Registered Member #103
Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845
Just been having a clearout and finding lots of interesting stuff!
This is the QRSS receiver I built/designed (in that order) for Chris's last QRSS transmission. The tricky bit was getting the crystal running at the right frequency whilst being stable. Notice how the crystal is taped up with toroid tape - I spent several hours 'inking' the crystal inside to shift its frequency, before taping it up. The thing was connected to a huge dipole that streched between the house and a tree at the top of the garden. Because I was lazy and needed to connect the dipole to the receiver inside, I simply cut the coax going to the TV antenna and used that
I never actually received any QRSS but it picked up a random US radio station really clearly
Registered Member #1107
Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792
you have just taken point to point soldering to a whole new level. It is nice though how that little thing that lots of people would think would never work can pick up a radio station from over 2000 miles away.
Registered Member #103
Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845
I built this digital thermometer the other day, to keep me entertained during my break from work!
The unique feature is that it uses some very old (late 70's?) display modules, which actually have their own incremental counter underneath the 7 segments themselves. I've had these things for ages, they came from a clearout at my old workplace! Interfacing is simple, just a clock and a reset line for each module, amongst many other unused pins of weirdness. The whole thing is powered by an Atmel AVR (Tiny13) with an NTC thermistor.
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It is nice though how that little thing that lots of people would think would never work can pick up a radio station from over 2000 miles away.
