Dave,
a coil having a proper resistor across doesn't have an high Q but the
meanwhile the low Q itself is not enough to prevent parasitics if the
suppressor design is somehow incorrect in some aspect (i.e. a too small
inductance) when such resistor is not effective, the coil Q is much
higher and the possible consequences becomes just opposed to what's
required in a VHF suppressor.
73,
> ---------- Initial message -----------
>
> From : owner-amps@contesting.com
> To : i4jmy@iol.it, amps@contesting.com
> Cc :
> Date : Thu, 22 Jun 2000 09:26:21 EDT
> Subject : Re: [AMPS] RF filament choke for indirectly heated cathodes?
>
>
> In a message dated 6/22/00 9:08:43 AM Eastern Daylight Time,
i4jmy@iol.it
> writes:
>
> > If ameritron does right or wrong is another story, but what I can
say
> > for sure is that without anode suppressor a 3CX1500 in GG is quite
> > stable and much less prone to VHF parasitic than other common
tubes
> > with conventional VHF suppressors.
> > The anode suppressors in the form of coil and resistors are
critical
> > devices whose effectiveness is very much questionable.
> > The true reason such suppressors are installed is to satisfy and
agree
> > conventional designs and expecially to let people to find out
what's
> > typically placed between the plate choke and tubes' anode.
> > Most of those suppressors are actually not working at all, and
finally
> > they aren't anything better than no suppressors at all.
> > Last but not least, when suppressors resistors are cracked
(typical)
> > oscillation risks are increased.
> >
> > 73,
> > Mauri I4JMY
> >
> Mauri,
>
> Perhpas you have some difficulty with the English language, but what
you have
> expressed above is non-sequitor. You say.....
>
> > "Most of those suppressors are actually not working at all, and
finally
> > they aren't anything better than no suppressors at all.
> > Last but not least, when suppressors resis
ors are cracked
(typical)
> > oscillation risks are increased."
>
> If the resistor/coil combination Really Isn't working AT ALL or is no
better
> than no supressor at all (ineffective), how can a cracked resistor
increase
> oscillation risks?
>
> 73 de
>
> Dave, WT8R
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|