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Re: Drake 2880 modiication results



wc0y wrote:
> 
> Modifications to my Drake 2880 are nearly completed.  These are the gain and
> noise figure results that I measured after different stages of modification.
> 
'snip 

> Gain = 38.7 dB, Noise Figure = 1.90 dB
> 
> The MGA-86563 device has the same performance at 2400 MHz as the MGA- 88576
> that others have used.  However, it is in a 6-pin miniature dual-in-line,
> surface mount package.  It can be mounted using the original pads by
> rotating slightly to fit. This modification turned out to be a very hard to
> do.  You will need many tools like tweezers, small-tipped soldering irons
> (two of these help), a  magnifier lamp, and lots of patience if you decide
> to do this one.
> 
> Thought I would pass these results on to help others starting to modify
> their Drake.

thanks Ward for your input , I was thinking of changing out the active device in
one of my drakes back when I first got 'em , but time seems to have slipped by ,
I picked up some MGA82563 phemt mmic's from an amateur on the microwave
reflector back then and didn't realize what I was buying till they showed up ,
man! talk about tight lead spacing ! , I hope I can squeeze it into the drake
without too much hacking , I wonder how much of a difference there is between
the '86563 and the 82563 ? , size and spec's , wonder if I will realize similar
gain/nf improvements .....

Curious as to how you made your noise figure measurements as well  ? 

I just measured how much the noise floor came up on the spectrum analyzer when I
connected the converter and powered it up , now I know that is not the "correct"
way , but does someone have a way to make a nf measurement with just a spectrum
analyzer and non tracking generator?

any help for us "amateurs" would be greatly appreciated :^)




-- 
Douglas Cole   N7BFS
AMSAT#26182 , K2 # 544
http://www.users.qwest.net/~cdoug3
Registered Linux user # 188922
"never go to bed angry , or on fire "
Gomez : the Addams Family.....
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