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RE: [linrad] A simple front end
Hello again Roger
I note that the R2Pro site prices the modules individually.
LNA (specify band) $12
Down converter $52
Analog processor $38
1 kHz filter $15
3 kHz filter $14
Audio amp $16
All together for $115- pretty good value it seems to me
Boards only $25
Thank you Leif for the tip about a cheaper way to get the +/- 45
degree phase shifts. I calculated the relevant component values for
14 MHz as I want to try the DC design for the first time.
>Yes, your "?????" and what you say [excerpted below] is really the point I was
>To make a longer note to explain what I was saying in the original email:
>The R2Pro consists of, in order of signal transit:
>Low Noise Amplifier Board
>DownConverter Board: TUF3's in quadrature followed by diplexer, etc.
>Analog Signal Processor Board
>Audio Amplifier Board
>The DownConverter Board has its diplexers just after the TUF-3's,
>and they roll off
>quickly [4000 Hz?].
>So you are I believe using only the RF amplifier board and the
>TUF-3's and throwing
>away everything else if you use the R2Pro for Linrad. This makes this route a
>relatively financially inefficient way to go and wastes a lot of
>parts and effort.
>I couldn't see taking the R2Pro and using just the RF amplifier and TUF3's and
>wasting the boards and everything else.
>It would of course be possible to redesign things and change the
>of the DownConverter Board from 0-4000 Hz to 0-90 KHz, and alter the
>stages as well, but I felt that if I was going to do all that, it
>would be just as
>well to start from scratch. Thus my comments.
>It would be possible to use just the LNA board with no mods followed
>by the remainder
>of your own front end, but buying the R2Pro just to get the LNA board is an
>expensive way to go vs just building that alone.
>There are some pages on the R2PRo at:
>They don't have the schematics. I DO have the schematics, but I don't have
>permission from Rick to post them.
>> > It is the audio phase-shift network
>> > and diplexer that I thought would not have the necessary bandwidth.
>> ????? These parts should be bypassed. Do not sum the signals in the
>> analog hardware - that is for Linrad to do.
>Any and all comments / corrections are appreciated!