[HamWAN PSDR] toys & tennas

[Bart Kus]

I just got word from Baltic that their next shipment of 5SHPn radios is 
6 weeks away, and is for 80 radios.  Looks like we're back to $100 land 
for the near term. Not a tragedy, just an annoyance.

Regarding the rotor, I'm guessing it does smooth start+stop.  This makes 
the speed non-constant during rotation.  Which means the angular 
positions are not easily deduced through timing and must be sampled from 
the rotor controller.  But you mentioned it does provide the current 
position at all times, so that should work. The RF strength samples also 
take an arbitrary amount of time to acquire, something in the region of 
100ms.  It's sounding to me like we need asynchronous IO on 2 
descriptors with timestamping and possible interpolation so we can spit 
out reliable (angle,signal) tuples.  Doing it by coming to a full stop @ 
each stepping will take too long, so the measures must be done while in 
motion and assigned to angles as best as we can.

Here's <http://pyserial.sourceforge.net/> a nice python serial port 
library.  I use the PyVISA <http://pyvisa.sourceforge.net/> library to 
communicate with the GPIB instruments.  WARNING: It requires Python 2.7 
series.  Or at least, I never got it working on Python 3.

--Bart


On 02/21/2013 03:38 PM, Rob Salsgiver wrote:
>
> Got 2 radios -- (5SHPn's) and one of the ARC-DA5830SD1's in today from 
> Baltic Networks.  So far received 2 orders from them and they seem to 
> be a dependable source.  Got a couple of rubber ducks and some 
> adapters to round out the package for a garage to house link so I can 
> do some playing around with the OS and a few other things.
>
> Ordered and received a Yeasu 5500 AZ/EL rotor with a FoxDelta ST-2 PC 
> interface (used).  Had to make the cables between the rotor control 
> box & rotor.  All tested out very nicely.  FoxDelta is a serial-port 
> driven interface that can also control the rotor via front panel 
> push-buttons.  The 2 line LCD shows programmed AZ and EL, as well as 
> current AZ/EL.  Protocol for commanding it seems to be very 
> straightforward and quite simple.  Character codes followed by  text 
> or integer values, sent via serial port. Current position can be read 
> the same way.   Calibrated the unit and put it through full rotation 
> testing via Hyperterminal <g>.
>
> Commanding and controlling the rotor should be fairly easy -- going to 
> start an application to do a predictable pattern of scanning for 
> measuring the antenna radiation patterns.
>
> Bart -- we traded a basic outline on the scan setup, but we'll need to 
> come up with however you want to coordinate the position control with 
> the measurement recording.  Do you want to have the position sent to 
> the test equipment, output the test equipment values to the PC to be 
> recorded with the position, or something else?  I don't know that I 
> need the info right this second, but we can start thinking about it in 
> the background.  Sunday will be my first day to play with it, but 
> barring Murphy it shouldn't take THAT long (famous last words..)
>
> Cheers,
>
> Rob
>
>
>
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