[amsat-bb] Re: Satellite tracking programming ideas

[Nate Duehr]

On Jan 28, 2008, at 1:00 AM, <phillor at telstra.com>  
<phillor at telstra.com> wrote:

> Reading the FT-847's receiver frequency originally caused me some
> frustration. I had included a delay after each read and write command
> because the
> FT-847 doesn't return a command acknowledgement. While writing this  
> reply I
> realised that instead of a delay I shroud be waiting for the serial  
> port to
> receive five bytes from the radio.
>
> This has turned out to be more reliable but I still get occasional  
> read
> errors and I feel that it's due to the USB to serial converter. When  
> an
> incorrect frequency value is read, at one second intervals, the same  
> value
> is reread from the serial port buffer each second until the  tuning  
> knob is
> moved again. Maybe the read command is working correctly and instead  
> it's
> the write command that instructs the radio to output it's frequency  
> that's
> not working reliably.
>
> I remember reading about some sort of delay that the FT-847 requires  
> but I
> cannot remember what it was all about. It could be important.


Phil,

Don't know if you're a "linux guy" or not, but the "snooper" package  
available on Debian Linux and derivatives, and certainly available  
upstream somewhere in source format for compiling on any other Linux  
system is a nifty tool for debugging such things.

Figured I'd share.  I ran across it in the package list one day quite  
literally by accident, (I was looking for other "snooping" tools like  
tcpdump and similar) and realized it was the perfect tool to allow me  
to become my own worst protocol analyzer.  :-)

It's kinda addictive to hook it up between serial devices you're not  
debugging and watch what's going on, too.

Great tool.  Simple, effective, and free.

(By the way, it's not installed on the machine below, thus the  
"unsatisfied" dependency... this is just a text capture of the package  
manager tool (aptitude) on one of my Debian machines, showing the full  
description.   Ignore the other cruft...)

-------

     --\  
snooper 
                                                                                                                                               < 
none>     19991202-4
   Description: Captures communication between two external serial  
devices
     Snooper passes data transparently between two serial (RS232C)  
devices, capturing and logging the data and occasional comments you  
want to insert into the logs.

     It is useful for debugging or analyzing the communications  
protocol between two devices that would normally be connected directly  
to each other, e.g. a digital camera and a
     personal computer.  By sitting "in the middle" (after you connect  
the two devices to serial ports on your Linux machine) snooper is able  
to capture data traveling in either
     direction while also passing it unmodified to the other device.

     It is also possible to operate with a single serial device, using  
your console and keyboard as the second device.

   Tags: admin::hardware, interface::text-mode, role::program,  
scope::utility, uitoolkit::ncurses
   Priority: optional
   Section: comm
   Maintainer: David Coe <davidc at debian.org>
   Compressed size: 16.6k
   Uncompressed size: 42.0k
   Source Package: snooper
   --\ Depends
     --- libc6 (>= 2.3.5-1)
     --- liblockdev1 (UNSATISFIED)
     --- libncurses5 (>= 5.4-5)
   --- Packages which depend on snooper
   --\ Versions
p    19991202-4

--
Nate Duehr
nate at natetech.com