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Re: Drake Conversions to 432 MHz



Hello this is Yoshi.

At 2001/05/20 18:55:58 Edward R. Cole wrote:
> Most information I have read states that no modification of the IF amp
> circuit is necessary when using a 432 Mhz IF.  I wonder what kind of gain
> is produced in this case.  Has anyone measured it.  Drake claims 21 dB gain
> for the stock 222-408 MHz IF bandpass, and I've seen claims for 15 dB gain
> using a 144 Mhz IF when the red coils and chip caps are removed from the IF
> circuit.

  Here is a english manual of 2880 at Mark's website.

http://www.markfossum.com/NewFiles/2880.pdf

  This manual did not listed the measured gain on 435MHz, but I feel
that it will be not so bad. 

  And, JN1GKZ Arai reported 430MHz mods of 2880. That page was only
written in Japanese, but he said it works well.

Drake2880 mods for 433MHz IF (Japanese)
  http://www.din.or.jp/~m-arai/sband/430if.htm

His English page (144MHz IF)
  http://www.din.or.jp/~m-arai/sband/convmode.htm

> The other question deals with the NF of the unmodified Drake.  Has anyone
> measure one at 2400 MHz?  The second question is more out of curiosity, as
> I will use a preamp ahead of the Drake.

  My basic modified 145 IF 2880 has 5.05dB NF and 24dB Gain. I do not
know the case of 435MHz IF, but it will not so much different. Mr.Yoshida
JI5MFZ reported that the NF of 2880 RF stage is less than 2dB so the
total NF for 435 IF (w/o IF mods) will be close to same as 145 IF.


Yoshihiro Imaishi JF6BCC/KH2GR
GL:PM53JV, ex KC6IY(T88IY),V63BP
mailto:jf6bcc@jarl.com or jf6bcc@jamsat.or.jp
<http://plaza16.mbn.or.jp/~palau/> Sorry, Japanese only now.
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