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				Homebrew gear for unlicensed spectrum
				Posted: Sun Dec 05, 2021 10:08 am
				by G4GUO
				Does anyone know what the rules are for operation of homebrew gear in unlicensed spectrum are?
Looking on the OFCOM website it says, as a guide, that if it has a CE sticker then it should be legal to operate.
But I couldn't find anywhere where it states it has to be type approved, so I am wondering if it would
be legal to operate if it meets all the emission regulations.
I am mainly interested in developing something to get around the prohibition on /AM operation by operating 
as an unlicensed service in unlicensed spectrum. WiFi and DJI occusync appear to be legal, but WiFi is not really
suitable for congested areas and DJI occusync is a closed protocol that can't easily be hacked.
- Charles
			 
			
					
				Re: Homebrew gear for unlicensed spectrum
				Posted: Mon Dec 06, 2021 10:39 am
				by M0DTS
				There maybe something useful to glean from the ukhas group who use 433 and 868mhz for airbourne downlinking from balloons.
Eg 
https://www.pi-in-the-sky.com/
I was going to investigate ways to get uWave receiver data down from a drone which i guess is what you are up to?
Rob
 
			 
			
					
				Re: Homebrew gear for unlicensed spectrum
				Posted: Mon Dec 06, 2021 12:25 pm
				by G4GUO
				Hi Rob,
Yes I was thinking of using either DVB-S2 / DVB-T from the drone at about 19 dBm with video and/or telemetry on the downlink multiplexed 
into the transport data stream. Then I could use our standard receiver hardware Knucker / Minitioune etc. That would be for my bespoke 
drone.
At the moment, I am using a Tello drone that uses UDP to upload commands and download video @ 720p using WiFi the video is 
being streamed into the jetson-inference library that runs a Neural Net on a ground based Nano or XavierNX.  
I am just doing object detection, but there is a 'monocular depth perception' net that can 'sort of' work out how far away an object 
is from the camera, that is the next thing to try.
The more expensive Tello EDU drone (same hardware different firmware) would have been a better device as it has more extensive command 
and control (it can also be flown in a swarm).
 
At the moment I am playing with a TP-Link Wifi range extender (TL-WR902AC) to increase the area I can control the drone over.
All good fun
- Charles
			 
			
					
				Re: Homebrew gear for unlicensed spectrum
				Posted: Sun Jan 16, 2022 11:02 am
				by g6jyb
				Beware
Anything must remain formally CE (or nowadays UKCA) approved - we have had such examples before where Ofcom have been very clear that 'emulations' of rf parameters do not qualify including amateur kit in CB and 446MHz allocations etc
73
 Murray G6JYB
			 
			
					
				Re: Homebrew gear for unlicensed spectrum
				Posted: Tue Jan 18, 2022 10:17 pm
				by g7ocd
				g6jyb wrote: ↑Sun Jan 16, 2022 11:02 am
Anything must remain formally CE (or nowadays UKCA) approved 
 
My understanding is many commercial outfits are self certificating that they meet such standards.
Surely if an amateur has (or has access to) calibrated equipment, are competent and can show the
methodology/traceability etc. they too could self-certify.
In the 27M and 466M examples, it's probably more of a case that the equipment can still be
tuned back to amateur bands which would obviously not meet the specifications.