SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

Stanley · 2014-12-01 13:43:41

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 :-

IMG_20141024_171337 by stanley_seow, on Flickr

2014-11-26 14.22.48 by stanley_seow, on Flickr

2014-11-26 14.19.46 C by stanley_seow, on Flickr

Singleboard version made by 9W2CEW :-

SVTrackR singleboard by stanley_seow, on Flickr

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

markqvist · 2014-12-01 14:28:15

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

Stanley · 2014-12-03 07:21:06

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

2014-12-02 21.48.19 by stanley_seow, on Flickr

Stanley · 2015-02-18 09:04:29

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% ...

SVTrackR 1W range of 11km by stanley_seow, on Flickr

1W radio, MCP601 op amp with SVTrackR by stanley_seow, on Flickr

1W 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)

Johan Adler · 2015-02-28 12:50:05

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.

Johan Adler · 2015-02-28 16:38:55

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)

Stanley · 2015-03-01 07:47:08

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..

Unsigned.IO Forum

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

SVTrackR - Cube style with MicroAPRS Modem and Arduino Tracker

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

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

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

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

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

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

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

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

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

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

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

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

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