Doug and the group,
If someone can help you by sending you the values measured, or listed in their
docs for 30M, that is great, but you have the key to doing it yourself. Just
take the values in the 40M region, and scale those to 30M, by the frequency
ratio factor! You know that by basic formulas, the values will be lower for
higher frequencies for both the caps and coils. The ratio of 7.0 MHz divided
by 10.1 MHz should give you the fraction to reduce the values by.
Use coils that can be squeezed or stretched for final tweaking, and you should
get a filter pretty close to the factory design.
Remember, some models had short lifetimes, and possible design problems when
the WARC bands transition happened. Things were changing, and no company
built very many of the radios that only could do the original bands at that
time, as there were doubts as to when permission could be had for the
additional WARC bands, and radios for the WARC additions were not in demand
until the bands had been available, and others saw what could be worked in the
new frequency ranges.
Hope you get it going, and have fun with it.
73, Stuart K5KVH
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