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[aprssig] APRS radios

Scott Miller scott at opentrac.org
Sun May 25 22:28:56 UTC 2008


I know of no processors that can directly execute code from NAND flash. 
  It's a bit like running from a hard drive - you've still got to load 
it into RAM first, because the interface isn't suitable for direct, 
linear access.

And the USB part doesn't really help either, since it's a function 
(i.e., client) only, not a host, and doesn't do anything besides mass 
storage.

Certainly there are more capable embedded processors out there, but a 
huge number of APRS stations are running on chips that cost under $3 in 
quantity.  The OT1+'s processor cost about $1.69 each (quantity 1000) 
when they first came out, and that's enough horsepower to do 1200 baud 
TX and RX in software, plus basic APRS parsing.  It's just a little 
tedious to work with.

And regardless of the amount of computing power you've got, it's 
difficult to implement an APRS parser correctly simply because of the 
ambiguity and complexity of the spec.

Scott
N1VG

Arnie Shore wrote:
> Kind of a programmer type lurking here, so feel free to shout me down if 
> this makes no real sense, but noting the cheapo multi-multi-megabyte 
> USB-connected dongles, mebbe this is a viable base for an APRS processor 
> in some more suitable language.
> 
> Arnie Shore
> 
> Pentti Gronlund wrote:
>> Bob Bruninga  writes:
>>
>>  
>>> Strict specs?  Since no one has implemented all of the protocol since 
>>> the oriiginal APRSdos written in BASIC no less, it doesn't seem that 
>>> one can call them strict....
>>>
>>>    
>>>> Maybe the other companies thought that the APRS radios were just too 
>>>> complicated to manufacture?       
>>
>> I'm not a programmer either, but based on the comments from the ones 
>> that are, this might be the reason. There simply hasn't been enough 
>> cheap embedded processing power until now. Good, maybe Icom will come 
>> with APRS/D-STAR radios one day, too. And maybe also
>> some new companies besides the Big Three. ...   
> 
> 
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