Hi The bandwidth *was* 10 Hz (or 10 cps) when it was made. Who knows what it is after 5 decades of aging. Same goes for the center frequency.
It’s not uncommon to see solder sealed crystals in low frequency filters. If they age 5 ppm per year, that’s doing pretty well. At 100 KHz, 5 ppm is 1/2 Hz. That would give you a 10 year “drift out of bandwidth” sort of life on the part. It also assumes the aging is linear with time (which it likely isn’t. The same sort of thing applies the the TC of the crystals. 100 ppm 0-70 stabilities are not unusual on LF filter crystals. That’s pretty major compared to the specs on the filter. Bob > On Mar 6, 2016, at 4:56 PM, jmfra...@cox.net wrote: > > Actually, the bandwidth is 10 Hz not 100 Hz. > > ---- Joseph Gray <jg...@zianet.com> wrote: >> Assuming I made the pictures small enough, attached are two images of >> an very old crystal filter that a friend found. The strange thing >> about it is the bandwidth - 100 Hz. What could this have been used >> for, with such a narrow bandwidth? >> >> >> Joe Gray >> W5JG > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
