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[AMPS] RF filament choke for indirectly heated cathodes?

To: <amps@contesting.com>
Subject: [AMPS] RF filament choke for indirectly heated cathodes?
From: i4jmy@iol.it (i4jmy@iol.it)
Date: Thu, 22 Jun 2000 16:15:28 +0200
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




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