On Sun, 20 Sep 98 17:03:51 -0800 Rich Measures <measures@vc.net> writes:
SNIP
>>>
>>>> as I use in parasitic suppresor
>>>>circuits on 6M along with MuMetal as the inductor.
>>>
>>>Mu metal is more resistive than copper, however, there are much more
>
>>>resistive alloys.
>>
>>More is not always better. At 330 Ohms/circular mil-foot,
>
>Shouldn't we be talking about RF resistance?
>
>>a Thermal
>>Conductivity of only .14, and a 2650 degree F melting point it does
>the
>>job and doesnt even get warm.
>>
>More resistive loss means lower Q, means more heat. A suppressor that
>
>"doesn't even get warm" is not doing much suppressing.
I guess you dont understand thermal conductivity. Besides you only want
enough RF resistance to do the job.
A 5" L x .5" W x .004" Thick length used as a plate strap for a pair
of 572B's will eat up about 50W at 50MHz. When used as a suppressor the
length is 2.5" by .25" wide.
How were the resistors measured? At what frequency? What was the
inductance of the leads?
The resistors as used here are a pair of 100 Ohm 5W MOX in
parallel....they do get a bit warm with a 3-500Z at 50MHz but not
alarmingly warm after a full minute key down.
Ciao, Carl
_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|