[GreenKeys] Tone frequency history?

[Richard Knoppow]

    Filing as described would lengthen the two tines slightly 
which should lower the frequency.

On 10/8/2021 8:13 PM, kn7sfz wrote:
> 
> 
> On 10/8/2021 6:54 PM, Jim Haynes wrote:
>> On Fri, 8 Oct 2021, Nick England wrote:
>>
>>> I wonder why 425 Hz tuning forks would have been common? 
>>> Musical A is 440
>>> and A-flat is 415.3.
>>> Maybe 2125/2975 came first and then 425 tuning forks? Hmmmmmmmmm.
>>> Nick
>>>
>> I remember an article about building yourself a 425 Hz 
>> frequency standard,
>> since so few of us had access to frequency counters in the 
>> early RTTY days.  The musical standard then and now was A=440 
>> Hz, but in an earlier
>> time it had been 435 Hz.  And there was someone who had a 
>> supply of 435
>> Hz tuning forks for sale. 
> 
> 
>> So what we were supposed to do was carefully
>> use a rattail file at the crotch of the tuning fork and file 
>> away just
>> enough metal to bring it down to 425 Hz.
>>
> 
> Would you not have to ADD weight to slow it down?
> 
> Just my 2 cents....😉
> 
> Richard de kn7sfz
> 
> 
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL