EMRFD Message Archive 2013

Message Date From Subject
2013 2008-09-06 11:22:34 bkopski PISTON CAPACITOR FOLLOWUP
Hi Ray, et al,

The previously posted subject was a preliminary look at an individual
resonator at about 400 mHz to determine a suitable tuning method /
device. The HB piston cap proved quite satisfactory and this allowed
completion of the real goal: a triple tuned fairly narrow 400 mHz

Two newly posted photos (see K3NHI folder) show the inside and
outside of the completed filter, and a third photo shows the measured
performance. This latter photo does contain a small error in that
the (violet) system reference trace is actually about 2 dB higher
than shown (test error) so the IL is really about 5 – 6 dB – as best
I can determine.

While the assembly shown does perform as shown, were I to do it again
I'd build an enclosure entirely of pc board in the interest of better
physical stability and lower internal leakage / section-to-section
coupling. The RCA connectors shown – here pressed into duty well
past the audio domain - are all I have to work with but do seem to
work satisfactorily for my purposes. The inductors are #12 "house
wire" and ½" id.

Cordially and 73,

2015 2008-09-06 16:04:42 Allison Parent Re: PISTON CAPACITOR FOLLOWUP
2017 2008-09-07 06:57:09 bkopski Re: PISTON CAPACITOR FOLLOWUP
Hi Allison, et al,

2018 2008-09-07 07:15:11 Allison Parent Re: PISTON CAPACITOR FOLLOWUP
2019 2008-09-07 08:46:17 bobtbobbo Re: PISTON CAPACITOR FOLLOWUP
2020 2008-09-07 09:50:19 bkopski Re: PISTON CAPACITOR FOLLOWUP

Bob, one needs to be CAREFUL in choosing RCA connectors because not
all RCA connectors are created equal. It seems various mfgrs take
some liberty with dimensions and I have experienced mfgr combinations
that could not be mated ('way tight) and combos that simply slipped
apart ('way loose). Having learned this the hard way, I've settled
2021 2008-09-07 12:16:52 Allison Parent Re: PISTON CAPACITOR FOLLOWUP
2022 2008-09-07 15:38:30 bobtbobbo Re: PISTON CAPACITOR FOLLOWUP
2030 2008-09-08 03:53:19 timshoppa Re: PISTON CAPACITOR FOLLOWUP