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Forum Index : Microcontroller and PC projects : Maximite APRS

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VK4SMC
Newbie

Joined: 30/12/2011
Location: Australia
Posts: 8
Posted: 04:59am 10 Mar 2012
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Hi,
My First post here, so hello to all.
Just a simple inquiry out of interest from a newbie.
Has anyone attempted any APRS / AX.25 code using MMBasic?
I'm not even sure it would be possible.
But I think it would be an interesting Major project.
I look forward to any replies.

Regards,
Steve VK4SMC
Steve VK4SMC
 
mookster1
Regular Member

Joined: 10/06/2011
Location: New Zealand
Posts: 81
Posted: 08:53pm 11 Mar 2012
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I have thought about getting the Maximite to decode shortwave radio faxes (such as those broadcast by our MetService here in NZ), and I've got it to generate RTTY messages (using ASCII not Baudot teletype at this stage...) but APRS sounds interesting.

BTW welcome to the dark side... I'm sure we can bake some cookies for you...
Capacitance is futile - roll on 2012!
 
VK4SMC
Newbie

Joined: 30/12/2011
Location: Australia
Posts: 8
Posted: 06:45am 12 Mar 2012
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Hi Mookster1,
Good to see you can generate RTTY messages. To me this shows AFSK possible.
Thought that would be the case, I presume that your using PWM to do that?
There is a few requirements to APRS least of all is the AX.25 protocol, which requires bit stuffing.
This is my main concern(bit stuffing) to start with and if that is possible then I will proceed from there. Looks like a lot more reading.
Think I saw a post from Geoff about bit bashing (or was that byte banging) Hmmmm.
Anyway sorry to ramble. Little steps for me.

Also I have the Kettle on ready for the cookies to arrive, it's nice when you move into a new area.
Steve VK4SMC
 
djuqa

Guru

Joined: 23/11/2011
Location: Australia
Posts: 447
Posted: 07:23am 12 Mar 2012
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A few of us Maximite / Duinomite owners who are also Amateurs need to work on a collection of programs/ routines/ solutions.
I am working on a Control Program for Yaesu CAT control
Edited by djuqa 2012-03-13
VK4MU MicroController Units

 
VK4SMC
Newbie

Joined: 30/12/2011
Location: Australia
Posts: 8
Posted: 09:41pm 12 Mar 2012
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djuqa,
That sounds like a very good idea putting our collective heads together.
Though I must warn you now that I'm only just a beginner and will be asking a lot of questions when I get stuck.
That said I am more than happy to help out in any way I can.
Just ideas - Do we start a separate group somewhere (shudder).
Do we just PM each other and post results.
Or the 10^6 options I can think of.
I would like to keep it open so other Hams can join in and also see the what has/can be done.
Anyway back to what I was doing
Steve VK4SMC
 
mookster1
Regular Member

Joined: 10/06/2011
Location: New Zealand
Posts: 81
Posted: 05:31am 13 Mar 2012
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All it (my program) did was generate different-toned beeps depending on if the bit is set so it may not be true RTTY (sorry, I did some brief reading into RTTY but I'm not a radio ham but I am interested in this stuff). It just sent it out the sound output to a piezo.
Capacitance is futile - roll on 2012!
 
VK4SMC
Newbie

Joined: 30/12/2011
Location: Australia
Posts: 8
Posted: 08:03am 13 Mar 2012
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mookster1,
I've been working on a very simple program to test the maximite audio output, just 1200 & 2200Hz.
Do you mind posting/PM your code so I can have a look?
Steve VK4SMC
 
mookster1
Regular Member

Joined: 10/06/2011
Location: New Zealand
Posts: 81
Posted: 08:13pm 14 Mar 2012
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Sure, I'll hopefully post it up this afternoon-ish (may be later, I'm quite busy at the moment)
Capacitance is futile - roll on 2012!
 
mookster1
Regular Member

Joined: 10/06/2011
Location: New Zealand
Posts: 81
Posted: 03:43am 15 Mar 2012
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Sorry, this is meant for loading from a text file but can be easily adapted to what you want.

'Modem
'Convert text to sound
Print "Text to RTTY for Maximite"
PRINT
PRINT "Note: Does not convert the characters to Baudot teletype from ASCII just"
PRINT "yet but uses the correct bit rate (calculated from baud)"
PRINT
bpsprompt: Input "How many baud"; bps
If bps > 1000 Then GoTo bpsprompt
bps = (1/(bps * 5)) * 1000
Input "Name of text file to broadcast"; filename$
Open filename$ For INPUT As #1
Do
Line Input #1, text$
If text$ = "Simon says stop" Then Exit do
text$ = text$ + Chr$(13) + Chr$(10)
length = Len(text$)
For a=1 To length
character$ = Mid$(text$,a,1)
Print character$
chardec = Asc(character$)
charbin$ = Bin$(chardec)
Print charbin$
'Convert the word into sound
For redpow = 1 To Len(charbin$)
'Separate a bit
bit$ = Mid$(charbin$,redpow,1)
If bit$="0" Then Sound 2125,bps: Pause bps
If bit$="1" Then Sound 2295,bps: Pause bps
Next
Next
Loop While text$ <> "Simon says stop"


Hope this helps!
Capacitance is futile - roll on 2012!
 
VK4SMC
Newbie

Joined: 30/12/2011
Location: Australia
Posts: 8
Posted: 11:13pm 15 Mar 2012
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Thanks Mookster,
This may help a lot.
Steve VK4SMC
 
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