[minima] Re: BSS-1 Transceiver Project
- From: "Jerry Gaffke" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "jgaffke@xxxxxxxxx" for DMARC)
- To: "minima@xxxxxxxxxxxxx" <minima@xxxxxxxxxxxxx>
- Date: Sun, 11 Jan 2015 19:34:55 +0000 (UTC)
Joe,
As you see fit, of course. But if for brief use during board checkout, I'd
keep the interface to the PC down to just the soundcard jack so it's easy to
replicate. Keep code and hardware as simple as it can be and still do the job,
so builders can fully figure out what's going on and how to hack it. Perhaps
both a simple version of your scaler analyzer, and a full featured one?
Crystal filter alignment seems to be the major stumbling block reported here.
Though I have no experience getting one to work, my guess is that it is
sufficient to do something like what follows. This was gleaned mostly from
reading previous posts, corrections welcome if I missed something. Include web
pointers in your documentation for those that wish to learn about fully
evaluating crystal parameters and run a Dishal program.
Buy twice the number of crystals needed from a quality supplier, perhaps ECS
surface mount through Mouser for those in the USA? (Using bargain priced
crystals is possible, but you will probably see much greater variation between
crystals.)
Choose crystals best matched for freq, using the Arduino to implement a freq
counter
Build a filter up using recommended cap values for that make of crystal, pots
at each end to adjust impedances
Dial in the pots for a flat response as seen in the sweep display on the PC
from the soundcard
Adjust the caps for desired bandwidth using formula provided, re-sweep and
re-adjust the pots.
Replace pots with L-Networks using formulas provided.
Re-sweep the completed receiver to verify proper filter operation.
Safe travels, hope you chose someplace warm.
Jerry, KE7ER
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