[GreenKeys] RE: [MMTTY] ve2lx reason for 2125 rtty freq

[jhhaynes at earthlink.net]

jhhaynes at earthlink dot net

On Thu, 28 Jul 2005, Veenstra, Lester wrote:

> there is another twist to this story. In the beginning, there were
> available 425 Hz tuning fork audio frequency standards from commercial
> terminal equipment , (this is part of my folklore although I have not

I'm not aware of those - however there were some home-built tuning fork
frequency standards described in the literature.  I recall there being
a source of 435 Hz forks (which I think was once the orchestral pitch
for A, before they went to A-440).  If you had one of these you could use
a rattail file on the bottom of the U in the fork and get it down to 425.
Then you had to mount the fork in a base of some kind and affix 
transducers, perhaps taken from an old headphone.