Peter -
>Dick says:
>
>>Both Tom and Jon have indicated that some RF goes through the resistors at
>>10M, contributing to the overheating.
>
>More fundamental current goes through the resistors as the frequency goes
>up, because of the increasing reactance of the shunt inductor. I suspect
>that because most parasitic suppressors are 'designed' on an empirical
>basis, very little (if any) thought is geiven to the actual dissipation in
>the suppressor resistors.
? Indeed, which is why I wrote "Calculating Suppressor Resistor
Dissipation ..." (March, 1989, *QST*).
>
>As far as having the resistors inside the inductor is concerned, many people
>got away with it for a long time. But it doesn't appear to be the brightest
>thing to do, does it, putting a lossy conductor tightly coupled to the
>magnetic field, such as to try to increase the RF current in the resistor?
>
? Perhaps a more likely reason is that the design of the carbon comp
resistor allowed itself to be used as a coil-form. Whether L-sup was
wound on top of or beside R-sup, the L and the R H-fields would have been
at the needed right-angle to each other. Increasing current in R-sup
simply requires increasing L-sup. However, more current in R-sup is not
always better. In order to achieve the optimal stagger-tuning effect for
a vhf suppressor, roughly equal currents (at the anode resonant
frequency) are needed in L-sup and R-sup. .
>
- later, Peter
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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