Wow, nice!
Rik/ON7YD, now its your turn again: What will be the ERP when running
100A in that wire? I think 100A is realistic on such a wire. Skin depth
should be 0.9 mm. So the effective conductor area 19 mm^2. Assuming 20m
x 30m (?) wire (=600m^2) means 100m length, so R ~ 0.15 Ohm. So Scott
gets 100 A rms when running 1.5 kW into the antenna (no problem for the
mains), without having problems of winding a large coil, without
resonating, without ferrite parts, without high voltages (but high
currents ;-) ). Am i right, Rik? And what is the ERP? I could take a
look on your website but you can do it so well here! What is the L and
Z and so the needed voltage to get 100A? :-)
Instead of standard FETs, some IGBTs could be used, shouldn't be a
problem at 9 kHz and some 100V. Any recommendations? :-)
Scott, what FETs do you use in your design? The IRFP460 is OK for 20 A
but not much more. One could do the effort and switch 4x 10 of them in
parallel but you'll need a good driver, maybe IXDD430... Interesting
stuff!
73, Stefan EI/DK7FC
Am 23.03.2011 06:55, schrieb Scott Tilley:
Hi Stefan
The mains has just to supply the losses. So the critical
parts are the FETs and the loop wire diameter. I think 100 A rms is a
problem for most loops. But i would give it a try. Even the 4x or 5x
1.5 mm^2 could take that current for a while, depending on the outside
temperature. BTW there will be a current limiting when the temperature
increases :-)
The loop here is a #2 AWG (6.5mm) AL conductor. And yes I note
considerable difference between cold days and warm ones on 2200m.
Somewhere I have some measurements.
Who is the one who does the first test? Scott? :-) BTW the distance
between VE7TIL and KL7UK is just 2084 km! http://no.nonsense.ee/qthmap/?qth=CN89DK&from=bp51ip
I pulled the h-bridge design of yours from my files and found a version
of this in my junk box... Now the magic question is when can I find
time to rig this up?
Scott, what do you estimate is the current limit of your
loop wire and what is the area? And what is the bearing?
Easily a couple hundred amps. 600m^2 and aimed right at Laurence. See
my website 'station info.'
73, Stefan/ EI/DK7FC
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