Mode Zero

OK, first don't panic (to use a well known phrase)! There's nothing fundamentally wrong with the project! There is, however, a "gotcha" in the setup, if you wish to remain strictly legal!

Our frequency allocation is 2400 to 2483.5 MHz. The output frequency of the module is determined by Fout=2400 + Channel Number MHz. This means that if you allocate any channel numbers above 83, you will be transmitting outside our allocated band, and could be placed on the "naughty" step if discovered!

To allow a suitable "guard band" at the band edges, I would suggest using channel numbers 1 to 82 (inclusive).

I think the UK band allocation is the same across most of Europe - certainly Sweden and France are the same. Outside of Europe, your mileage may vary, so check your local regulations and adjust the channel numbers accordingly!

I discovered this by accident when I looked at the output of my Ponty sweepstake prize on a spectrum analyzer. Speaking to Tobe, he'd just gone with Phil's original suggestions for channel allocations, unaware of the issue. I've contacted Phil about it, and he says that it was discussed in the original thread, but if I missed it and Tobe missed it, the chances are more of you have.

Tobe is now busy re-programming his own systems, and has kindly sent me an updated sketch for mine. I suggest that if you have programmed any channel numbers above 82, you do the same.

The chances of getting caught are remote, but we enjoy a relatively relaxed enforcement agency in the UK. I wouldn't want to see that jeopardised!

--
Pete

Lack of knowledge is not a valid defense or excuse so here I have included a chart showing how 2,4 GHz is allocate around the world. nRF24 has 125 channels in 1 Mhz increments 2,400-2,525, which is 2400 to 2525 MHz (MHz) and as said the nRF24L01 channel spacing is 1 Mhz which gives 125 possible channels numbered 0 .. 124

#define MY_RF24_CHANNEL X, where X is the number to the left below
0 => 2400 Mhz (RF24 channel 1)
1 => 2401 Mhz (RF24 channel 2)
76 => 2476 Mhz (RF24 channel 77) standard
83 => 2483 Mhz (RF24 channel 84)
124 => 2524 Mhz (RF24 channel 125)
125 => 2525 Mhz (RF24 channel 126)

I wondered who the 2.4835 - 2.5 GHz has been allocated to and its primary users are active medical implants and land/satellite base stations. Even if Ofcom don't check up on us, we'd better make sure nobody is nearby with a medical device like a insulin pump or insulin monitor for diabetics (unfortunately this includes my daughter) or monitored heart pace-makers (a few as my club) if using a transmitter out of band.


If you want to see who frequencies are allocated to, Ofcom has a nice website checker:
http://static.ofcom.org.uk/static/spectrum/map.html#

Mike

I love Ofcom's chart but they are by sure not intended for color blind people!
Concerning medical implants communication fortunately every message/ packets of data has at the end a check code so unintended signals are just disregarded. Actually every packet of data is sent so many time per period so at least one will reach destination w/o interference...but no doubt we should avoid to interfere.
Today in medical devices we have started to consider "radio signal pollution" and I'm sure you could guess why!
Certification of medical implants software defined with some kind of remote functions could cost in the range of several 100 millions $...

For those of us in Australia, our 2.4GHZ band is: & in New Zealand: