An even simpler 2.4g spectrum analyser / band scanner

Any old or new electronic projects on the go
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Phil_G
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Joined: 15 Feb 2018, 23:32
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Re: An even simpler 2.4g spectrum analyser / band scanner

Post by Phil_G »

Hi Max, I think the low amplitude is down to how the hopping code and the scanner work together:
First the transmitter: the NRF code sends a very small packet of a couple of hundred microseconds, every 5ms, so Its utilisation of each channel is under 5% (MU ).
And the scanner: the NRF24 has no facility for RSSI, it can only tell us if the signal on any channel is above or below -64db, so its more of a "carrier/no carrier", yes or no signal. Martins code uses this to detect the amount of time any channel is in use, ie has an active carrier on it - it cant test the carriers signal strength.
So in combination we have a transmitter that transmits for only a tiny fraction of the timeslot, and a scanner that displays the amount of time a channel is occupied. I think this is why the peaks are much lower than say DSM2 or any high MU source like FASST Image
A high MU is good if you are the only one to have it - its not so good when everyone has high MU gear :D
Like everyone shouting in a noisy pub! Hence ETSI EN 300 328 V1.8.1. 2 :D
MaxZ wrote: 09 Jul 2020, 11:56I made a scanner using a Tstar Tech red board, using the code version that Phil created for it.
just to be fair I didnt create anything, its 100% Martins code :D I only changed a couple of configuration options - asking for sprinkles doesn't make me a Gelatist :lol: :lol: :lol:
Cheers
Phil
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Flynn
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Joined: 17 Feb 2018, 14:48

Re: An even simpler 2.4g spectrum analyser / band scanner

Post by Flynn »

scanner.jpg
scanner.jpg (50.2 KiB) Viewed 42663 times
Ummmmmm.... how does that work Martin? How come the two left-most screens display an output without any connection to data or clock? Is that a really good photoshop job, some whacky parasitic crosstalk or some devious cabling under the breadboard?
You only ever need two tools....WD40 and duct tape.
If it doesn't move when it should use the WD40 and if it moves and it shouldn't use the tape.
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Flynn
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Joined: 17 Feb 2018, 14:48

Re: An even simpler 2.4g spectrum analyser / band scanner

Post by Flynn »

Phil_G wrote: 28 Jan 2023, 10:26 For the photo Martin simply moved the yellow & white clock and data connections along the displays, to save wiring it 3 times :)
Thats why the 3 DSM2 plots differ slightly, the displays were clocked a few seconds apart after moving the connections and resetting the RF-Nano.
As long as power remains the display retains the screen contents without clock & data, its a static device ;)
Cheers
Phil
Phew!.. thanks for the explanation Phil......I thought I was going to have to re-evaluate my understanding of breadboard construction there......
You only ever need two tools....WD40 and duct tape.
If it doesn't move when it should use the WD40 and if it moves and it shouldn't use the tape.
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