Fellow Topbanders:
Another Hi-Pass filter is shown in the 1986 ARRL Handbook on page 30-24. It is also shown in other ARRL Handbooks. The original article was published in QST in Feb 1978 and was written by W3NQN, Ed Weatherhold. Charlie, W0CD, found he could spread a coil or remove a turn to "customize" the rejection for local stations. Although we do not have an actual filter-response curve, we were able to move F4 up to 1400 KHz to nul a local broadcast station just over a mile from my QTH, which seemed to also move the start of the attenuation closer to 1.8 MHz. This arrangement worked well for me with an AM 930 station running 1 KW at night only 1/2 mile from my QTH whether I was using a beverage or pennant receiving antenna that was receiving signals that had to pass by the AM 930 station to get to my QTH. YMMV GL & 73 & HNY George K8GG _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK