#1 2014-12-01 13:43:41

Stanley
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From: Kuala Lumpur, Malaysia
Registered: 2014-12-01
Posts: 65
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SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

This is my Arduino based APRS Tracker based on MicroAPRS modem with SPI OLED display ...

My initial blog posting :-
http://9w2svt.blogspot.com/2014/07/buil … -aprs.html

Github Repo :-
https://github.com/stanleyseow/ArduinoTracker-MicroAPRS

Pictures :-

15734804928_4a9eee0c49_m.jpgIMG_20141024_171337 by stanley_seow, on Flickr

15896454006_a0d7d12099_n.jpg2014-11-26 14.22.48 by stanley_seow, on Flickr

15736228879_8021860c07_n.jpg2014-11-26 14.19.46 C by stanley_seow, on Flickr

Singleboard version made by 9W2CEW :-

15922305165_c84a7df0a2_n.jpgSVTrackR singleboard by stanley_seow, on Flickr

Last edited by Stanley (2014-12-01 13:52:20)


Stanley
9W2SVT/ N5SVT
http://9W2SVT.blogspot.com

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#2 2014-12-01 14:28:15

markqvist
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Registered: 2014-12-01
Posts: 109

Re: SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

This is great Stanley! It's just awesome having it mounted in your car like that! Thumbs up!

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#3 2014-12-03 07:21:06

Stanley
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From: Kuala Lumpur, Malaysia
Registered: 2014-12-01
Posts: 65
Website

Re: SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

Thanks to Taner's compression decoding codes from MicroAPRS.h, now the SVTrackR can decode mic-e packets ...

15910059546_b2b375e58a_n.jpg2014-12-02 21.48.19 by stanley_seow, on Flickr


Stanley
9W2SVT/ N5SVT
http://9W2SVT.blogspot.com

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#4 2015-02-18 09:04:29

Stanley
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From: Kuala Lumpur, Malaysia
Registered: 2014-12-01
Posts: 65
Website

Re: SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

I managed to get the 1W Radio working ( similar to Dorji radio but this is from Sunrise with SAME AT commands ) ...

The 1W radio can be powered directly from Li-On battery but I'm using 5V voltage from USB and drop the voltage using a 1N4001 diode to 4.3V ...

I've also added a MCP601 (0V-5V) op amp to smooth out the received audio output , this improved the packet decoding to 90-100% ...

15945664754_67785a2775_n.jpgSVTrackR 1W range of 11km by stanley_seow, on Flickr

16380559748_56ea043352_n.jpg1W radio, MCP601 op amp with SVTrackR by stanley_seow, on Flickr

16380559298_5590d042ea_n.jpg1W Radio AF out peak to peak voltage vs peak to peak after MCP601 op amp at 5V by stanley_seow, on Flickr

Last edited by Stanley (2015-02-18 09:07:09)


Stanley
9W2SVT/ N5SVT
http://9W2SVT.blogspot.com

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#5 2015-02-28 12:50:05

Johan Adler
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From: Stockholm, Sweden
Registered: 2015-02-28
Posts: 3

Re: SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

According to RA3APW it seem possible to power the Dorji module with 5V. The RDA1846 chip tolerates 4.8V according to the datasheet, but I have not looked inside my DRA818V modules to check how it actually handles the power input. I think that 4.8V ought to be safe.

RA3APW claims to have achieved close to 1.5W (31.7 dBm) RF output in the high power setting using 5V, but recommends some cooling system if you intend to have a high transmission cycle. The power consumption when transmitting at 31.7 dBm is 5W, so you would need to dissipate 3.5W heat, I guess.


SA0CLI at JO99AE87BR
Stockholm, Sweden

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#6 2015-02-28 16:38:55

Johan Adler
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From: Stockholm, Sweden
Registered: 2015-02-28
Posts: 3

Re: SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

Adapting DRA818V AF output to Teensy 3.1


I realize that an opamp is a very nice way to adapt the signal level, do you think that this approach might work too?

The Dorji module's audio output is 700 mV according to Dorji, the R8/R9 voltage divider should create a voltage just above that, which is fed to AREF and also used, using the R6/R7 voltage divider, to offset the audio signal to the center of the ADC span.

Last edited by Johan Adler (2015-02-28 16:46:19)


SA0CLI at JO99AE87BR
Stockholm, Sweden

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#7 2015-03-01 07:47:08

Stanley
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From: Kuala Lumpur, Malaysia
Registered: 2014-12-01
Posts: 65
Website

Re: SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

Johan,

Thanks for the tips on the higher output power.... as APRS packets are short and quick, hope it can take the higher RF output power for those brief moments...

Not sure about the specs, but from the picture of the AF output voltage on the scope, it can reach really really high, Vpp of 24V ...

You would have to test out the circuit and measure the Vpp voltage to be sure...

This is my FIRST time dealing with op amps ... but I find them to be very nice to keep the AF output voltage constant no matter what the AF output voltage was... high or low..


Stanley
9W2SVT/ N5SVT
http://9W2SVT.blogspot.com

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