Blank PC Boards for Charleston Receiver

Frank Gentges fgentges at
Mon Jul 27 21:17:46 CDT 2009


I am replying to you and cc:ing to all the others on tacos that may have 
missed the activities on the project.  Terry and the group in Charleston 
have been doing the heavy lifting down there; thus the name.

Go over to the web site at

I had 10 boards made and they came out at $20 each.  The parts for each 
board look to be about $67 + shipping at last count.  We had hoped to 
get it in at $60 and maybe later.  This board is seriously surface mount 
but I have a solder paste stencil to help everyone along.  I still have 
some boards if you or anyone else wants to join in the fun.

In addition, you will need to buy a Nexsys2 board from Digilent.  You 
can order one at,400,451&Prod=NEXYS2

The basic board at $129 has 500k gates and for $40 more you can get an 
"enhanced" version with 1200k gates.  They have a special price for 
qualified students but I don't think my 1965 ID will work for this.

Right now I do not know enough to figure out if the larger number of 
gates is useful and I have the 500k version for now.  It reminds me of 
the days when we used 4k of memory and were happy.

All the software can be downloaded for free so that part of the project 
is free and I am looking at making up a data DVD with the essentials.

What you end up with is an 76 megasamples/sec 12 bit front end and 
enough software to get from the antenna input to the computer USB port. 
   A `4 or 16 bit front end would be more desirable but not at a low cost.

We have a spectrum analyzer program that runs under Windows that can use 
the Charleston USB stream.  We also have a set of GNUradio programs you 
can run under Linux right now.

There is WINrad that we think can be adapted with minimal effort to act 
as a spectrum display and demodulator under Windows but we need to write 
the dll to do this.  I am confident we can adapt this and Alberto, 
I2PHD, WINrad's author can give us help over any rough spots.  He has 
written a guide to go with the source code that should be very helpful.

The attraction of the Charleston project is that with all these gates we 
can design FPGA functions to do better than we can do in the computer 

Gate based signal processing was hot in the early 70s but processors 
took over.  Now with FPGAs we can slide back to the future and get a lot 
more performance with FPGA implementation than with a stored program 
processor since the FPGA can execute in a massively parallel form.  We 
have the lowest cost approach for experimenters to learn with a hands on 

In a nutshell, this is what it is about.


Glenn Baumgartner wrote:

> Frank what is the cost of an assembled board?  May I assume you have the 
> Software to run it ?  got any specs on this board.  I've been gone a 
> while and missed much of the discussion.  Sounds interesting from what I 
> do know. Glenn b.

More information about the Tacos mailing list