On 11/23/2017 10:25 PM, na5n_qrp wrote:
Jim Kortge writes:
Mike et. al.,
I just ran a design using the Goldmine Electronics 13.5 MHz crystals
... and the crystal parameters from my web page that I measured a long time ago, it looks like a 500 Hz Cohn filter can be made.
Thanks, Jim, for running the analysis (and posting the data). That was my "gut feeling" that a bandwidth of around 500 Hz, if not higher, would be the result, but didn't state that as it was just a guess at the moment.? Thanks for confirming the suspicion.
Interestingly, a filter with narrower bandwidth can be made, but the terminating impedances are very low and the inserting loss goes up to unacceptable levels.? That's why I went with the 500 Hz filter.
On 30M, that should make a decent filter for the signals usually heard up there (enough to filter out those occasional RTTY and FAX signals!).
It should work out just fine for 30-Meters.
Hope you, and everyone, had an enjoyable Thanksgiving.
Thank you, we had a great day with family.? Hope you and Jan enjoyed yours.? After surviving Lymphoma last fall and this spring, I'm probably as thankful as anyone around to still be alive.? There were a couple of close calls.? I'm getting my enthusiasm back to designing and building again with a couple of projects on the bench that I've been working on.? One of them is a redesign of the 4017 Transverter, but this time in a general format with DDS to set the band where it will be used and microprocessor control of needed functions.? Hardware and firmware at its finest!? :-)
72, Paul NA5N
72, 73 and sure nice to hear from you; all the best,
Jim, K8IQY
Jim Kortge, K8IQY