Tim Wescott wrote:
KC4IH wrote:
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?
There used to be great big resistors -- essentially carbon composition
-- that were truely noninductive. I suspect they're still available. My
1988 handbook has a UHF dummy load design that features a Carborundum
part number 889SP500K. With coolant it's good for more than 1500 watts,
so it may be oversized for you...
You can still find the occasional 2W or 5W carbon comp resistor -- if
you're working at HF you can easily parallel these to get the resistance
that you need.
These are a smaller version:
http://www.ohmite.com/catalog/pdf/a_series.pdf