Thanks Brad, It's great to have your formula.
Ye Olde Junque Box here has a box of 80 FT-241s from a BC-604. They are the
two digit
version.Just miked the pins and they are the same spacing and diameter as a
FT-243
so they should be good for 455 kc bfos etc.
73 Pete NV4V
At 06:27 PM 3/20/2002 +0000, Brad Hernlem wrote:
>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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