Questions on ARRL 813 Rig

<< < (3/3)

W3RSW:
Here's a nice coil calculator, Q, Z's, turns, etc.  I think it was already referred by this site.

 I'm referencing his pi net page but you can back into his other Java calculators.
I used it on my 813's and came out pretty darn close.
http://www.qsl.net/wa2whv/radiocalcs.shtml

WA1GFZ:
a two watt resistor is good for maybe 500 volts I would not use one over 1kv
A lot safer to series up a bunch. Also use your final volt meter as an additional path so you can see the voltage decay. If the time changes you have a problem.

W3RSW:
Correct.
In my HV meter string, I used 6 each 1 meg. 3 watt resistors (IRC thickfilm 5%, Mouser P/N 66-GS31001004JLF, rated 1kv each) with a final 1k resistor to ground. The 500 micro-amp meter being picked off right above the 1k resistor.  So the HV circuit is always to ground through reasonably safe 6.001 meg. string.  Same wiring for the screen circuit and hot switchable on the 1k pick-off. Found both to be in circuit continually.  Frank, your the catalyst that's clarified my thinking yet again; this time for an extra added attraction, Safety.

  Note that I'm not too concerned about absolute accuracy, just relative and watching the rate of charge/discharge.  Pretty neat watching the HV drop faster than the screen due to the relatively smaller filter cap. in the HV string, diff. time constants, etc.

Navigation

[0] Message Index

[*] Previous page