[Amps] Ferrite Rod

[Tom W8JI]

Hi Jim,

> Larry,my initial thought was to urethane clear coat .125 
> in. copper tubing

I would not use copper tubing. Copper tubing is great at 
Radio Frequencies where skin depth is shallow, but not for 
high current lower frequency stuff.
Current rating at low frequencies is related to conductor 
cross section. .125' thin wall copper tubing is about like 
using #10 AWG wire.

You'd be much better off in heating and voltage drop using 
solid copper wire.


> and wind enough turns around paralled ferrite rods to get 
> what I need...I
> planned to isolate the filament trans anyway,so added 
> chokes in the primary
> may be effective in eliminating filament 
> hum/modulation..PWD makes a nice
> high current choke too( for around 300.00 or so

You can get into all sorts of funny things with this. At 
some frequency the choke will series resonate with the 
transformer capacitance and you will have no choking 
impedance.
Either use one or the other, not both.

A choke works easiest at higher frequencies, while an 
isolated transformer and no secondary choke works best at 
lower frequencies. A floating transformer can really be bad 
at the 30MHz  end.

73 Tom