[aprssig] TNC-2 tuning and temperature stability
archer at eskimo.com
Mon Mar 13 09:40:25 CST 2006
On Sat, 11 Mar 2006 scott at opentrac.org wrote:
> The idea with the tighter tolerance parts is to leave enough margin that
> even given the widest variation in values, it'll still be within spec across
> the whole operational temperature range.
You have both the initial tolerance of the parts and the changes as
the parts age. Plus add in possible temperature/vibration/shock
extremes that might change the values of the parts as the users
abuse the devices.
I'd suggest leaving the pot in there, but that's the cautious
approach. You may do just fine by spending a few cents on higher
precision parts and skipping the pot. Only time and a few irritated
users will tell. ;-)
Curt, WE7U. APRS Client Comparisons: http://www.eskimo.com/~archer
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