In case the resistance become very high or infinite, not only the
suppressor doesn't work but there's an increased risk to have
parasitics than without the damaged suppressor.
When amplifier power is large enough and the reactance of the
suppressor coil is also high enough to produce in the resistor an RF
current flow that's beyond its capability (more frequently it happens
on 28 MHz), or the resistance rises until a balance point is found, or
the resistor breaks (opens).
A large number of conventional suppressor one can see when opening HF
amplifiers show a resistor that has been evidently overheated but a few
people take the charge to measure what's the actual resistance of those
burned resistors.
73,
Mauri I4JMY
> ---------- Initial message -----------
>
> From : owner-amps@contesting.com
> To : Fred Fliss <fredfffff@hotmail.com>,
amps@contesting.com, "'Paul Christensen'" <paulc@mediaone.net>
> Cc :
> Date : Thu, 3 Aug 2000 13:47:08 +0100
> Subject : RE: [AMPS] Suppressors, measurements, and acrimonious
blather
>
>
>
> Paul says:
>
> >the standard use of the classic coiled wire on a carbon composition
resistor.
>
> I have a nasty suspicion that one of the problems with the classic
suppressor
> is that the carbon comp resistor is pushed pretty hard in terms of
dissipation,
> especially on the higher bands, by the fundamental current. Add to
that fact
> that the resistor is in a high temperature environment as well, all
of which
> isn't good for reliability. The result is that the resistor value
goes high, and
> a suppressor that worked becomes a suppressor that doesn't work
anymore.
>
> 73
>
> Peter G3RZP
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