[ARC5] Using SCR-274N

[Bill Cromwell]

On Fri, 2013-03-29 at 09:54 -0700, Dennis Monticelli wrote:
> I have fancied going the crystal filter route with the BC-453 (with
> converter ahead for the ham bands).  Unfortunately, 85KHz resonators
> are not only hard to find, then are very high in impedance. The hi-Z
> makes them hard to graft into the IF chain without a lot of loss.  It
> can be done, but it takes more work to do it in such a manner that it
> is easily reversible.  A better route is probably using a fast op amp
> configured as an active filter.  You can use a modern hi-speed op amp
> these days at 85KHz and still get good Q.  It would be small and could
> run off a step-down from the DC filament voltage.  I would experiment
> with this if I had the time.
> 
> 
> Dennis AE6C


Hi Dennis,

The IF strip in a BC-453 or R-23 is already pretty narrow with the tabs
pulled all the way up..their narrowest setting. I get single signal
reception and when I plug in the NEScaf filter is chokes right down to
narrow CW bandwidths - less than 100 hurts. I am thinking of the xtal
filters (or Q-multipliers) for the 80 and 40 meter receivers. A guy on a
Harley rode right through on my 40 meter receiver (evil grin). He passed
a VW bug that was already coming through the IF.

73,

Bill  KU8H