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[aprssig] APRN status?

Stephen H. Smith wa8lmf2 at aol.com
Sat Mar 27 22:50:25 UTC 2010


Joel Maslak (N7XUC) wrote:
> On Fri, Mar 26, 2010 at 12:54 PM, Stephen H. Smith <wa8lmf2 at aol.com 
> <mailto:wa8lmf2 at aol.com>> wrote:
>
>     Due to the complex DSP required to process the multiple QAM tones
>     in  real time, about the minimum PC that will run EasyPal is a
>     700-800 MHz P-III with a true-hardware-based soundcard; i.e. not a
>     "brain-dead" software-based motherboard el cheapo sound system. 
>     It MAY be possible to get the highest-powered netbooks, now that
>     their processors are pushing 1.5 GHz, to run EasyPal, but I
>     haven't had the chance to try this yet.
>
>
>
> I wonder if an iPhone would work...has a camera, screen, and audio 
> in/out interface...
>
> I'll have to do some thinking.  But it would be a handy "field" device 
> to use for capturing a picture and displaying received pictures via 
> radio.  And costs of an iPhone (particularly a used one without cell 
> service) aren't all that different from what the Kenwood box goes for.
> ------------------------------------------------------------------------

There are three separate issues here:

1)      Currently the proprietary EasyPal program is exclusively a 
Windows thing.   EasyPal uses a varient of the DRM (Digital Radio 
Mondiale -- not "Digital Rights Management) compression/modulation 
format developed for digital shortwave broadcasting.   If one could gain 
access to the details of the transmission format, possibly it could be 
duplicated on other platforms.     [Details on the older analog SSTV 
formats are all over the web but somewhat conflicting.]

2)     Does the iPhone have enough CPU "horsepower" to decode the 
multiple QAM audio subcarriers in real time?     From a platform 
stand-point, it sounds ideal given the built-in hardware --IF-- the CPU 
is fast enough.    How decent is the iPhone's camera?   Does it overload 
and wash out in daylight?

3)     The cost differential is academic -- the Kenwood is no longer 
available.     


------------------------------------------------------------------------

--

Stephen H. Smith    wa8lmf (at) aol.com
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