Homebrew gear for unlicensed spectrum

Discussion and announcements about ATV related spectrum
Post Reply
G4GUO
Posts: 702
Joined: Tue Feb 16, 2010 12:51 pm

Homebrew gear for unlicensed spectrum

Post by G4GUO » Sun Dec 05, 2021 10:08 am

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

M0DTS
Posts: 535
Joined: Sun Feb 24, 2008 9:03 pm

Re: Homebrew gear for unlicensed spectrum

Post by M0DTS » Mon Dec 06, 2021 10:39 am

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

G4GUO
Posts: 702
Joined: Tue Feb 16, 2010 12:51 pm

Re: Homebrew gear for unlicensed spectrum

Post by G4GUO » Mon Dec 06, 2021 12:25 pm

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

g6jyb
Posts: 32
Joined: Thu May 09, 2013 12:57 pm

Re: Homebrew gear for unlicensed spectrum

Post by g6jyb » Sun Jan 16, 2022 11:02 am

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

g7ocd
Posts: 14
Joined: Sat Jul 12, 2014 7:36 am

Re: Homebrew gear for unlicensed spectrum

Post by g7ocd » Tue Jan 18, 2022 10:17 pm

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.

Post Reply

Return to “Spectrum matters”