Note
73, Sep 1975, p. 48.
QST, Nov 1975, p. 156.
Ham Radio, Mar 1976, p. 92.
QF-1A
QST, Jan 1979, p. 149.
QST, Jan 1980 p. 113.
QST, Apr 1981, p. 204.
QST, Jan 1982 p. 209.
Autek called the QF-1 an "infinitely-variable" filter to combat interference in any mode. One knob adjusts its frequency from 250 to 2500 Hz, in all 3 positions. Zero-in on any signal without touching your receiver.
Peak CW, RTTY, etc. with selectivity variable from 50 Hz to flat. Help eliminate whistles, CW, etc. with a wide, deep (to 70 dB) notch. With variable width & frequency. Reject SSB, AM, FM, etc. hiss & splatter in the sharp-cutoff lowpass position!
Uses an IC op amps and a power amp. 1 Watt peak to speaker or phones. Use with any receiver or transceiver made.
Power: 115 VAC.
Also available as the QF-2, the basic circuit-board for custom installation. Requires 6 to 30 VDC. Less power amp. etc.
References
Review. QST, Mar 1977, p. 44.
