HAB project, Radiometrix NRX2 & Arduino. I need some help!

Hi everyone! I am planning on flying a high altitude balloon soon, and my goal for the first payload is to transmit GPS data back to earth. I was following the example found here: http://ukhas.org.uk/guides:linkingarduinotontx2 when I ran into a problem. That tutorial uses a Yaesu transceiver, which I do not have as they are quite expensive. What I do have is a Radiometrix NTX2, Radiometrix NRX2, 1 Arduino Uno, and 1 working standalone ATmega328. I can set up the transmitting part of that tutorial with the ATmega and the NTX2, but I could use some guidance in setting up the NRX2 with the Uno.

What I have tried so far is to connect the power according to the NRX2 datasheet pinout, and to link the audio output pin to A0 on the Uno. I then used the example sketch “AnalogInOutSerial” to convert whatever was coming into A0 into something readable on the serial monitor. Being a very amateur operator, I tried waving around a yagi (that I hooked up directly to the breadboard via BNC) to see if the numbers on the serial monitor would change due to random interference. I noticed that when I waved the antenna around, there was an increased amount of outlying data (I was seeing more 15 and 16 compared to 2 or 3). After that, I tried running both the NTX2 and NRX2 at the same time, and I noticed that the yagi picked up much more outlying data compared to when the NTX2 was off. Would you consider this a success? I was still receiving a lot of 2s or 3s, so I am not sure whether this worked or not.

I am not sure if this pertains to these forums, but how would I send the data coming out of the NRX2 to a computer program called FLDIGI? I will need to use it for decoding RTTY from the balloon, but I do not know how to configure it. Thank you!

Hi Mr Shrimp,

The NRX2 isn't suitable for receiving the SSB RTTY the tutorial I wrote generates. However you can use a cheap SDR (Software Defined Radio) to achieve the same result at a fraction of the cost. There is a tutorial on this here : http://ukhas.org.uk/guides:sdr_tracker.

I sell modified EZCAP's on my online shop, come speak to us on IRC http://ukhas.org.uk/ukhas:irc_channel


M0UPU / Upu