Some years ago I built some 9:1 xformers for the 6 beverages at the
W3GM contest station. I used some small binocular ferrite cores that
were used in CATV cable tap boxes. They worked great thru the
fall/winter contest season. The following fall, while getting the
station ready, we found that several of the beverages were "dead". I
inspected the antennas and they were ok. Upon opening the xformer
boxes, I found that the ferrite cores had disappeared and only the
windings remained! Apparently, nearby lightning had disintgrated the
cores. All the xformers were then rebuilt using cores approximately 1
inch in dia. with heavier and we never the problem again. Just
another case for making the matching xformers reasonably "robust".
73, Stew K3ND...
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