[time-nuts] Re: World's most accurate PC clock!

Flemming Larsen flarsen at sbcglobal.net
Mon Jul 4 01:55:14 EDT 2005


Or the 10.245 MHZ and 11.155 MHz crystals used for
converting 10.7 MHZ first IF to 455 KHZ second IF.

144.56 MHZ was used in Europe as a simplex channel
on 2 meters, as the 11.155 MHZ crystal was widely
available.

  (11.155 * 12) + 10.7 = 144.560

-- Flemming Larsen



--- Javier <javier at nebulosa.org> wrote:

> Narrowband FM used in land mobile radio and amateur
> radio usually has 
> 25, 20 or 12.5 KHz channel spacing. 10.24MHz was
> mostly used in CB 
> radios with a MC145106 or similar PLL IC, and with a
> double purpose: to 
> obtain a 5KHz PLL reference and also as the 2nd
> local oscillator to 
> convert 10.7MHz first IF to 460KHz second IF.
> 
> This reminds me another widely used crystal
> frequency for the list: 
> 12.8MHz is used in radio transceivers with 25 and
> 12.5KHz channel 
> spacing, since 12.5KHz PLL reference is 12.8MHz /
> 1024 (and also another 
> discrepances: 60.005 would be 60KHz with a 5Hz IF,
> no 5KHz, and also 
> 77.503 would be 77.5KHz with 3Hz IF, no 3KHz).
> 
> Regards,
> 
> Javier, EA1CRB
> 
>




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