Re: FW: RE: [TowerTalk] SteppIR VS Force 12

[Jim Lux <jimlux@earthlink.net>]

At 11:16 AM 2/19/2004 -0800, N6KJ wrote:
> Yes, one could imagine this, but I would propose something that I believe
> would be even better (and would serve other useful purposes).  I would
> propose that the SteppIR team provide an API by which you could control
> the antenna from your PC.  All of the adjustments you suggest could
> be done using a PC based program and then given to the controller to change
> the antenna.  This could potentially reduce the cost of the controller,
> allow for 3rd party development of new "features", and would allow
> for remote control of the antenna (something not possible today).

Rather than an API (which implies some software running on a host, and 
calling sequences, etc. that would have to be managed), why not use serial 
communications...

Some simple fixed width or comma delimited format, terminated by CR

EL,1,330<cr>

sets element 1 to 330 cm long
Or, even, raw "stepper clicks" for position.

You could also have some "readback" type commands:
EL1?<cr>

or higher level functions:

FLIP<cr>

PRESET,5<cr>

BAND,40<cr>


You could then write some software driver that would expose a callable API 
(or embedded activeX or .NET or CORBA or whatever the interface d'jour is)


Heck, if you just had the interface replicate pushing the buttons on the 
front panel it would be useful.

On a general note, I think this kind of functionality should be in ALL 
microprocessor controlled widgets these days.  Antenna rotators, relay 
boxes, antenna tuners. I wish antenna tuners had it, for instance, so that 
you could manually control L and C)

Given that you might want to remote control these sorts of things over many 
feet of wire, RS-232 is probably not the best interface, though.  20 mA 
current loop?  RS422? Open collector switches with optos.

One could pattern the protocol after those used in IEEE488.  Easy to parse, 
easy to understand, etc.



Jim, W6RMK

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