[amsat-bb] Re: Drake 2880 Downconverter

[Yoshihiro Imaishi <imaishi@xxxxxxxxxxxx>]

Hi this is Yoshi.

At 2000/12/31 13:45:56 Ed Krome wrote:
> I would like to know if it is possible to make the downconversion to 420
> Mhz by substituting another crystal.  I have no info on the oscillator
> circuitry in the downconverter and do not know its limitations. Could a
> 7.??? Mhz xtl be used.

  Some of Japanese hams did it. PLL generates 256 times signal from
Xtal oscilater. If you want to 

JN1GKZ Drake 2880 Mod. Info for 144 IF.
  http://www.din.or.jp/~m-arai/sband/convmode.htm

JN1GKZ Drake 2880 Mod. Info for 430 IF (Japanese only).
  http://www.din.or.jp/~m-arai/sband/430if.htm
Modification Photo.
  http://www.din.or.jp/~m-arai/sband/mod5.jpg
  (1) Replace Xtal to 7.69531MHz for 2400>430 or 7.66406MHz for
      2400>438. Maybe 7.734375MHZ for 2100>420.
  (2) Power it and check the Voltage of Blue point. It should 4 or 7 V
      if PLL locked. 1 or 2 V will unloked.
  (3) Replace and re-allocate the capaciter chip of Red point to
      10pF. And the check PLL lock again.


Yoshihiro Imaishi JF6BCC/KH2GR
mailto:jf6bcc@jarl.com
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