I have a digital data signal with frequency in the 434-438 MHz band. The data is BFSK modulated with frequency deviation of 9.6 khz, baud rate of 1200 bps. The bandwidth is 25 Khz. Is there a way I can receive the above signal on Kenwood TS-2000. The maximum deviation of TS2000 on BFSK mode is 850 Hz. But can I receive the data by using the TS200 in FM mode ? Is the baud rate of 1200 bps supported by TS2000 ?
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3 Answers
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Ashish, you should be able to receive this using FM. I'm not sure what the BFSK mode of the TS-2000 is but the data should be visible in FM mode. You will then have an audio square wave (or rounded if there is some bit shaping).
If you feed the audio into a computer soundcard, you should be able to record the data with something like Audacity and see the bits. That will give you confidence that you can demodulate it from there.
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$\begingroup$ The square wave will also be rounded off by the high-frequency response of the FM receiver. $\endgroup$– Kevin Reid AG6YO ♦Jun 12, 2015 at 19:44
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$\begingroup$ @Chris: Will we able to receive the data if it is not encoded in ax.25 protocol but uses synchronous protocol with preamble and synchronization word ? Will we able to receive the data using ARCP software ? $\endgroup$ Jun 17, 2015 at 18:51
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$\begingroup$ I know nothing about Kenwood radios or the ARCP software. You would probably need to decode it yourself by feeding the audio into a soundcard. If it's a standard protocol then MixW or something like that may decode it. If its something as part of a research project, then you will need to write the decoder. We would need some more context to help further. $\endgroup$ Jun 19, 2015 at 13:55
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$\begingroup$ @Chris: Thanks for replying and apologies for late reply. The data is encoded using a custom protocol consisting of preamble and sync words and no flags which are used in ax.25 packets. In this, would it be possible to decode the data from the sound-card. How can we proceed with writing the decoder ? Will the TS-2000 forward the data to soundcard if no flags are used in the data packet ? $\endgroup$ Aug 15, 2015 at 10:08
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Kevin Reid has the most important point-- +/-9.6 kHz is beyond the +/- 7.5 kHz bandwidth of the TS-2000 receive filters. Without first modifying the hardware (replacing filter), I would expect the receive signal to be distorted, quite possibly beyond use.
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This may be obvious. Signalink from Tigertronix is the sound card of choice for the digital radio of which I'm aware. Also the program soundmodem which does not support BFSK may be a starting place for building a decoder if the author is willing to be supportive. KK4MG
