KKANALZ@prodigy.net sez:
>Be careful, guys! Most FT-241 crystals were originally designed and used
>for "Tank Radios", FM on about the 10M band. The crystal blanks in the
>FT-241 holders, however, are NOT ground for the frequency
>(ies) marked on the holders, but are *much* lower in frequency than marked
>on the case (you'll usually see a "Channel" number and a frequency marked
>on the *top* of the housing).
>The (relatively) high frequency shown is the *output* RF frequency of the
>transmitter, having been multi-
>plied several times for FM-ing the transmitter to get some deviation. It
>is *not* the ground-frequency of the crystal blank.
There are at least two series of these crystals; one that has channel
numbers with three digits and one with two digits. The fundamental frequency
(in Mc) of the three digit series is simply found by dividing the channel
number by 720. The two digit series have a fundamental that is equal to 20
plus the channel number divided 10, the result divided by 54.
Example:
Channel 273 has operating frequency of 27.3 Mc but fundamental of
27.3/72 or 379.166 kc.
Channel 54 has operating frequency of 25.4 Mc but fundamental of
25.4/54 or 470.370 kc.
Brad KG6IOE
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