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Re: Drake frequencies



At 06:43 PM 2/13/01 +0000, Frederick M. Spinner wrote:

>2400MHz -> 120 MHz...
>//
>The if mods with the 22 pf Caps may need to be increased to, say,
>27 pf to work at 120 MHz optimally-- as the peak gain on my converter is 
>around 153 MHz or so with the 22 pf mods..

Hi Fred,

How did you determine "peak gain"?  By maximum S-meter reading/noise?

Last weekend, I put the 22 pf caps in my Drake, and I'm using the stock 
xtal for the very reasons you guys mentioned (at least to verify the unit 
works.)  Maybe I'll convert the xtal to 144 after some preliminary 
testing--seems my IC 706 would be good with the 120 MHz, but I don't think 
my old TS-790A is quite up to the task down at 120 MHz.

With the 22 pf caps, my unit has maximum "S-meter noise" below 120 MHz 
:(  Basically, it seems to decrease noticeable about 121 MHz or so and 
higher (right around where AO-40 is!), but seems quite a bit louder *down* 
the band....

I'm not sure how the cap values needed are being calculated?

I can't really comment on my modified Drake yet, as I haven't had any AO-40 
passes where I could test it (and I don't really know about my homebrew 
helix yet, either...).   I have a pair of Wimo helices coming this week (or 
next), so I'm looking forward to being able to do some S-band comparisons 
at my QTH soon!

73,


Mark L. Hammond  [N8MH]

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