Lee,

If you look at Files > Lite+Xtall v8.3 there is a folder with plots of
the V8.3 bandpass filters all on one page. This gives you an idea of
what is possible for general coverage with the un-modified V8.3 kit.
You essentially get 3.5MHz to 30MHz contiguous coverage with some
small compromise around 8MHz to 10MHz.

I am programming the Si570 with a Parallax Propeller chip
(www.parallax.com). Right now I have ten ham-bands (160m-6m) in a
table of Si570 register values with 20kHz frequency steps. There are
two switches for up/down frequency and two switches for up/down band
selection. When you change between bands there are outputs to
automatically switch between one of five band-pass filters. I do not
calculate the Si570 register values in the Propeller chip (yet), the
register tables are pre-calculated. I intend to replace the ham-band
tables with general coverage tables in 10kHz steps. The frequency
display is via a four-line by twenty character serial LCD.

I have not received my V8.3 kit yet. I do have Si570's working though.
When I receive the V8.2 kits I will build some sort of band pass
filter switching to be controlled by the propeller, probably using DIP
relays or PIN diodes.

Instructions on how to program the Si570 are included in the data
Si570 sheet. I didn't need anything more than the data sheet and the
Excel spreadsheet that comes with the Si570 Evaluation Board software
which can be downloaded from Silicon Labs to get the Si570 working.

73's David

--- In [email protected], Lee Buller <[EMAIL PROTECTED]> wrote:
>
> 
> 
> Dear List People....
> 
> The light is dawning the more I read about SDR.  The Si570 seems to
have been a great innovation for SDR type radios since the device can
be programmed to fit the desired frequency.  I do have some questions.....
> 
> What is being done to program the Si570 now for various bands?  I
know that there is some people doing this already, but the information
is hard to find.
> 
> It seems the new version and its PIC controller has taken into
account band changes including upper and lower band edges, but forsake
the middle of the band.  Is there software to "tweak" that issue (I am
not a programmer, but I do use programs).
> 
> I am interested in getting an RX for not only the ham bands, but
General Coverage as well.  That would mean tweaking the Si570.  Is
anyone out there doing that now?
> 
> I have read a lot about sound cards.  I see a lot of information for
various bandwidths.  What is the sound card standard?  Now, I do not
want to invest in a 300 dollar card, but I want to know what is the
best bang for the buck.
> 
> The light keeps getting brighter as I read the technical papers
concerning SDR.  Not bad for a Liberal Arts major.
> 
> Could someone comment on the Si570?
> 
> Lee - K0WA
> 
> 
> 
> 
> 
> In our day and age it seems that Common Sense is in short supply. 
If you don't have any Common Sense - get some Common Sense and use it.
 If you can't find any Common Sense, ask for help from somebody who
has some Common Sense.  Is Common Sense divine?
>


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