It's not practical for me to go through the entire process
of parasitic construction. To be honest, I don't think it's
an exact perfect science and my opinions seem much
different than many amps members. So I go my own
way and have had very good results with my work. I
just happen to have the benefit of very good test
equipment to use.
I'll try to dig out my suppressor construction file and
detail some of the steps I used, but from memory only...
I'll mention some of the high points here. I don't wish
to tie up a lot of time rehashing things that have been
posted on here by many, subjects that are detailed on
Rich's web site. Other information is available in the
ARRL and Radio Handbooks.
The last "test sets" of SB-220 suppressors I constructed
contained both Nichrome Ribbon and wire inductors in
20 to 80nH values, across Rich Supplied 100 ohm
3 watt MF resistors (the blue type).
The most practical suppressor I now use in the SB-220
is 40nH Nichrome wire wound in a coil, matched on
the LC-102. The ribbon did not appear to suppress the
vhf response as well as wire. I prefer the "lumped"
wound coil vs the "hoop" coil option many use.
I've tried 5/6 watt MF resistors with great luck and now
use them in my suppressors. To be honest, I have not
measured the "bare resistor" inductance, but like the
3w resistors Rich supplies, the stray L appears
relatively small in value.
I also prefer the coil type inductance for size reasons,
but avoid the resistor in the center location. Both sit
happily in parallel adjacent to each other.
: From: 2 <email@example.com>
: What band and mode were you using when
: R-supp burned out?
: Did R-supp measure infinity (?) with an
: ohmmeter or just changed R?
The high end of the 10 meter voice band. The old
suppressors are actually still in one piece, sitting
on my server desk. I guess I'll measure one
: So the self-declared "expert" wants to know how
: to determine how much L and R goes in a suppressor.
: I published this info on AMPS. If he was paying attention,
: he would already know. Will said that Rauch kill-filed me.
: cheers, Skipp
: R. L. Measures, 805.386.3734,AG6K
It would save me a lot of typing to include the above so
Tom will see it and refer to the amps archives if he
wishes to debate the topic with you again.
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