[Coco] Ham Radio

jdaggett at gate.net jdaggett at gate.net
Mon Nov 10 18:56:01 EST 2003


John

I downloaded the APRS protocol document and looked at it. It appears that APRS 
uses only the AX.25 UI frame. It appears that only 1200 baud is supported, maybe 
2400, for VHF/UHF. It is a tight squeeze to get 9600 baud in a VHF channel width of 
15KHz. The AX.25 UI frame is a max of 332 bytes and interesting that the color 
pallette for the map symbols is 16 colors! 

I think if you tried to have the OS9 do the TNC functions along with 
decoding/encoding UI frame along with display functions maybe a bit to much. Then 
there is the einterface to the GPS receiver!I think it will be enough to handle the UI 
frame and then dice that up and process that data. The way the Lat/Long data is 
encoded and decoded is strange. Factoring by 91^2 then 91^2, then 91^1 is a bit 
strange but then it becomes obvious that the person behind the creation of APRS, 
WA4APR, is an ex military personnel. Often the term Tactical location appears.  

Personally I think that APRS is an overkill for general traffic. I can see where it can 
catch on though. With all the different packet switches and the meriad of 
&^^&%$tors that have proliferated amature radio, APRS is considerably simpler. AN 
old 286 computer, a 1200 baud TNC and a VHF radio and away you go. Know worry 
as to how to configure the TNC for this mode or that mode or this and that protocol. 
I can see the usages for emergency communications and public service. But using it 
to surf or acess the Internet from a VHF radio at 1200 Baud is a bit slow by modern 
standards. 

james 

wa4bzj
 

On 10 Nov 2003 at 13:07, john donaldson wrote:

>    Now APRS seems to have taker over from Packet. When I 
> lived in Houston, Texas most of the packet networks had 
> very
> little activity, but the APRS network was very busy and 
> growing.
>    I wonder if APRS could be programed to run on a COCO3
> under OS9 or NitrOS9??
> 
> John Donaldson
> AB8YZ
> 
> 
> On Mon, 10 Nov 2003 11:52:17 -0500
>   jdaggett at gate.net wrote:
> >
> >
> >That is KA9Q software. 
> >
> >The last itme I used packet here in So. Fla it was a 
> >mess. About 8 yrs ago. Half the 
> >state was Rose, (northern part) and the other, (southern 
> >part) was Net One. just to 
> >get a connection from Ft. Lauderdale to Jacksonville 
> >required the right phase of the 
> >moon. Jupiter needed to be in Sagitarius and the wind had 
> >to be out of the south. 
> >Then you might have the connection for about an hour 
> >before some link in the 
> >middle failed. Typical hop was Ft. Lauderdale to Ft. 
> >Myers, to Sarasota, to 
> >Aracadia, to Orlando,  to Ocala, to Palatka, then to 
> >Jacksonvile. The link from 
> >Arcadia to Orlando was the weakest one. At 430 Mhz it had 
> >the longest haul. Using 
> >400Mhz around the east central part of the state is 
> >limited. Cape Kennedy and 
> >Patrick AFB restricted radiated power. Essentially there 
> >was a wall in central 
> >Florida, Considerig MacDill AFB in Tampa, McCoy NAS in 
> >Orlando and the Cape 
> >on the east coast.. McCoy is gone now and McDill AFB has 
> >reduced importance so 
> >that should have freed up a lane to the north.  
> >
> >One of these days I may just check again to see if the 
> >service is more reliable and 
> >better performance. 
> >
> >james
> >
> >WA4BZJ      
> >
> >
> >
> >On 10 Nov 2003 at 8:48, john donaldson wrote:
> >
> >>    I used to run KN9Q (sp) on my MM/1 and had a ball 
> >> talking
> >> to other hams using it and watching traffic over the 
> >> packet
> >> network.
> >> 
> >> John Donaldson
> >> AB8YZ
> >> 
> >> 
> >> On Sun, 09 Nov 2003 22:15:32 -0800
> >>   <jimcox at miba51.com> wrote:
> >> >John:
> >> >
> >> >Drop me a line some time, I'd like to learn more about 
> >> >packet radio.
> >> >
> >> >Jim
> >> >
> >> >On Mon, 27 Oct 2003 17:12:55 -0800
> >> >  "John Guin" <johnguin at hotmaill.com> wrote:
> >> >>Hello all,
> >> >>
> >> >>I was reading Jim Cox's mail about not pursuing ham 
> >>radio 
> >> >>work with the Coco
> >> >>in the Seattle/Bellevue area.
> >> >>
> >> >>I'm also a ham radio operator in the Seattle area, and 
> >> >>have had antenna
> >> >>restrictions to deal with as well.
> >> >>
> >> >>Back when I had my packet radio set up, I used a 19" 
> >>long 
> >> >>antenna made from
> >> >>#12 wire and got reception and transmission good 
> >>enough 
> >> >>from West Seattle to
> >> >>the node closest to my condo - about 3 miles away.  I 
> >> >>used my old 2 meter
> >> >>handheld, and it worked very well.  It only had one 
> >>watt 
> >> >>of transmitting
> >> >>power.  That's all you need to get started on packet
> >> >>
> >> >>IIRC, there was actually a packet article or two in 
> >>the 
> >> >>Rainbow, but I'm not
> >> >>sure how useful the information would be.  The packet 
> >> >>modem does most of the
> >> >>work, though, so the easiest thing to do with a Coco 
> >>now 
> >> >>would be to use a
> >> >>terminal program to log data.  Since the Coco uses a 
> >> >>standard voltage on the
> >> >>serial port, it is not as hard to connect the modem as 
> >> >>some other 8 bit
> >> >>machines (Commodore, I'm talking to you).
> >> >>
> >> >>Anyway, the point of this letter is not to let antenna 
> >> >>restrictions keep you
> >> >>off the air.  Unless you were wanting to get involved 
> >> >>with Clover or some of
> >> >>the other low frequency modes, a really cheap "coat 
> >> >>hanger" antenna sitting
> >> >>in a window is all you really need.
> >> >>
> >> >>73,
> >> >>John Guin
> >> >>KB7ZJW
> >> >>
> >> >>-- 
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> >> >>http://five.pairlist.net/mailman/listinfo/coco
> >> >
> >> >
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> >
> >
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