Hi Guys,
Results of the build and test were that the 7Mhz HPF worked very well with
the "6" grade cores, but the 20Mhz LPF was crap (it used #6 as well). It
started to roll off at 20Mhz as expected, dropped smoothly to -10dB by the
time it got to 40Mhz, then stayed at 10dB at all frequencies above 40Mhz.
I suppose the core should be a grade #10 or #12 instead of #6? or perhaps
just a normal air core?
JEFF


"Jeff" wrote in message
...
Thanks for all the suggestions. Ive got some Amidon T68-6 toroids to wind
up, and will test the completed filter on a spectrum analyser next week.
JEFF

"Jeff" wrote in message
...
Hi,
Im confused regarding the choice of iron powder toroid for a 7Mhz high
pass
filter. I need to use a small size (T68) toroid. For the freq range,
some
reference texts say T68-2 is the one, others say T68-6" grade. I see
differing "best Q range" specs for the 6
grade.....2-30Mhz......10-50Mhz...etc.
Have similar need for 20Mhz LPF, but assume "6" is really the choice
there.
Any suggestions as to the relative differences and reasons to choose
between
grades 2 and 6 for the HPF in T68 size?
Thanks,
JEFF