Thanks Ralph, that is what I was thinking but when they are advertised as
non-inductive you would think "non-inductive" wouldn't you. I guess I'll
have to dig around in some old junk boxes or parallel several 1 watters to
get them to work.
I appreciate your information.
Ken

"Ralph Mowery" wrote in message
nk.net...

"KC4IH" wrote in message
...
I need to build a 3db pad, 50 ohm, 10 watt, to reduce the drive to my 6
meter amp. I need 2 X 300 ohms and 1 X 18 Ohm resistors and thought it
would
be an easy matter to find them with enough current rating to do the job
but
can't find anything larger than 1 watt carbon (not film, which are
somewhat
inductive ) resistors. I can find want is called non-inductive wire wound
resistors. I can't understand how a wire wound resistor can be
non-inductive. Could someone explain this?

By winding the wire so the inductance cancels out you get a noninductive
resistor. They are really noninductive at low frequencies. Once you get
above the audio range they become inductive. I doubt they would work for
your case.

KC4IH wrote:

Thanks Ralph, that is what I was thinking but when they are advertised as
non-inductive you would think "non-inductive" wouldn't you. I guess I'll
have to dig around in some old junk boxes or parallel several 1 watters to
get them to work.
I appreciate your information.
Ken

Crazy idea but I'll throw it out here anyway.

We know that carbon film resistors have some worriable inductance at 6
meters. If a guy were to take a group of say 1-watters to make up the
power rating, could you count on the consistency of the outer markings
to the extent that you could group them somehow in parallel/inverted so
that they cancel each other's inductance in this application?

-Bill

In article ,
KC4IH wrote:

Thanks Ralph, that is what I was thinking but when they are advertised as
non-inductive you would think "non-inductive" wouldn't you. I guess I'll
have to dig around in some old junk boxes or parallel several 1 watters to
get them to work.
I appreciate your information.

Check out the Caddock and Vishay noninductive metal-foil resistors.
As I understand it they use a serpentine-path foil pattern, which
cancels out the inductance quite nicely. Some of them are advertised
as having an inductance equivalent to an equal-length piece of wire.

They're available in packages such as TO-220, and can be attached
directly to a heatsink (no insulator required).

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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