PixiePi
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lu7did
RTTY implementation
hey, is RTTY script only working with a pixie transreceiver or is it meant to use with GPIO4 pin directly?
You can use it just with a bare Raspberry Pi extracting the RF signal from GPIO4, however:
- The power will be much less, in the order of 10 mW instead of some 300-400 mW.
- You MUST protect GPIO4 by extracting the rf thru a 100 nF capacitor, otherwise it's likely you'll short circuit the pin and fry it.
- You MUST put some sort of band pass or low pass filter in order for the signal to be reasonably clear of spurious and armonics (please see the readme.md on the subject).
- Obviously, you'll be able to only transmit and not to receiver the response.
73 de Pedro, LU7DID
10 mW is enough for me, I'm going to make a passive bandpass filter for the pin, now I'm making some pspice simulations. However, will 10 mW fry my pin? Do I have to put the capacitor for just experimenting before I make the bandpass filter? Because Im not going to wire an antenna yet. And for the receiver side, I'm using RTL-SDR with fldigi on my PC to decode the signal. Not expecting receiving anything on rpi side. Just transmitting.
If you're not going to use an antenna probably a low pass filter won't be that necessary, still I would recommend not to connect anything to the GPIO4 unless it's thru a 100 nF capacitor in order to exclude any chance of a short circuit. 10 mW won't fry anything, a CC short circuit might.
Also, you'll have better "local" results if attach some short piece of wire (10-15 cm long) as an antenna, won't radiate far away and will improve significantly your local signal strength.
How you decode is inmaterial, as long as you don't use the rbpi for that. See the "whisper" script on the OrangeThunder/bash directory for some ideas on how to implement transmitters on several modes.
73 de Pedro, LU7DID
Thank you very much.
One last question, how should I compile this script? I've already installed the rpitx, Should I compile this with librpitx.h? And since you moved the location of repository, I think your installing instructions on PiRTTY.cpp is irrelevant.
The script, either on BASH or Python doesn't needs to be compiled. The program can be found already compiled in the directory bin of the PixiePi package, or you can clone the whole package and build it again from sources. 73 de Pedro, LU7DID