> > >Dan Hearn, N5AR wrote:
> >
> >>I have been using these resistors (Globars) in parasitic suppressors for
> >>many
> >>years . Has anyone ever had one of these fail or change value without a
> >>change in external appearance?
> >Like you Dan, I've used the small Globars for years for parasitic
> >suppressors and now, more recently for glitch protection and never found
> >any problem whatsoever. I also saw them in use for some commercial
> >multi-kW amps, by Create Eng., with the same units.
>
> A 6" long ''non-inductive'' Globar resistor has over 100nH. One
> disadvantage to Globars is that the length to diameter ratio tends to be
> too high - typically about 6 or more to one. The L/D ratio for a vhf
> suppressor resistor needs to be low - otherwise the desired
> stagger-tuning effect is not obtained. Cesiwid/Globar/Kanthal can make
> such resistors on special orders of 1k minimum units.
> >
The 10 ohm globars that Eimac uses on their 4-1000A amps that I described
earlier
are 2.5 inches long and .75 inches in diameter. The 50 ohm units from SSN are
1.87 inches long, and .5 inches in diameter.
(((73)))
Phil, K5PC
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|