Video Transmission module for Really High Altitudes - Page 1
Forum section: electronics / projects

author: yaxsomo
author_rank: Newbie
timestamp: August 22, 2024, 09:37:37 am
content: Hello Everyone,I'm pretty new here, but I already done lots of electronics projects before.I want to launch myself into a big challenge : A Video Transmitter and Receiver that streams 1080p video over a 180Km altitude!I've ever done this kind of project before but I find it really interesting!I wanted to first gather you opinions on this project before start working on it. Which considerations do I have to take into account? Do you think that it would be better to have directly a camera that does embedded video processing and just take the video OUT for streaming?Thank you in advance!

author: tggzzz
author_rank: Super Contributor
timestamp: August 22, 2024, 11:30:38 am
content: Quote from: yaxsomo on August 22, 2024, 09:37:37 amMake sure your transmissions are legal.If they aren't legal then from 180km(!!) altitude the transmissions will cover a wide area and are likely to cause interference to other users. That may cause law enforcement to visit you.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 22, 2024, 11:38:08 am
content: some systems use signal conversions to do high distances like microwaves etc .. i used such a system4 x video signals at the same time many many (40) miles away, just a matter to face them / align properlyand some provide tools to help align ... or use a signal strength meterand yes it could interfere, if it is not beamed (focused), too wide area range, power levels etc ...cellular modems ?? video over cellular .... but normally you'll need to compress your signal, if not it's over a 1gb/sec bandwidthyou need 4g or 5g networks

author: pcprogrammer
author_rank: Super Contributor
timestamp: August 22, 2024, 11:56:41 am
content: Quote from: tggzzz on August 22, 2024, 11:30:38 amOnly if they know it is you who put that transmitter at 180km altitude.It will be quite the challenge to get the camera with transmitter and power source to go up that high and keep it there for some period of time to be able to send something interesting down to earth. In the mean time crossing the 10km aviation height, you better make damn sure you don't take a plane down too.

author: Silenos
author_rank: Regular Contributor
timestamp: August 22, 2024, 12:03:43 pm
content: Why do you need to receive 1080p video on the 180 km altitude?

author: Andy Chee
author_rank: Super Contributor
timestamp: August 22, 2024, 12:20:25 pm
content: I assume this is some sort of amateur helium balloon experiment?Getting an amateur radio licence would be the normal legal way to send live video feed to the ground.See here for some ideas:https://arhab.org/For balloon operators who don't have amateur radio licences, they just send up a GoPro and record video to SD card, and retrieve the SD card when the payload descends via parachute (with GPS beacon, and loudspeaker beeper to assist in retrieval).

author: yaxsomo
author_rank: Newbie
timestamp: August 22, 2024, 03:12:40 pm
content: Thank you for the responses!!It's actually for an amateur rocketry project!! I'm testing my current navigation modules and flight modules and they are working pretty great!! The last module to add is the communication module, that will embed a powerful radio transceiver for telemetry and a powerful video transceiver for live feed.The 180Km is an "ideal" altitude, so I'm sure that on much lower altitudes it behaves really good. It would be great to be able to change remotely the power transmission so the module can adapt to regulatory laws.There's some projects here in france, in collaboration with the CNES and Ariane Group that can give authorizations on this domain for a short period of time..Do you guys have some reference designs or schematics both for telemetry and video transmission/reception that works great on high altitudes to start with ?

author: Andy Chee
author_rank: Super Contributor
timestamp: August 22, 2024, 03:21:45 pm
content: What is your maximum payload weight? This will dictate the battery size and power of your video transmitter.

author: tggzzz
author_rank: Super Contributor
timestamp: August 22, 2024, 03:33:04 pm
content: Quote from: Andy Chee on August 22, 2024, 03:21:45 pmDon't forget that at the low temperatures at high altitude batteries will have higher internal resistance (lower power) and reduced capacity. Those effects cause problems in gliders at a mere 25000ft / 8km

author: yaxsomo
author_rank: Newbie
timestamp: August 22, 2024, 03:41:04 pm
content: We’ve scheduled a launch on 2025, with those characteristics:- Wet Mass : 110Kg- Altitude Target : 4Km- Motor : PRO-150 o8000- Max Thrust : 8605N -> 0.877 Tons- Total Impulsion : 40.900 N/s -> 4.17 Tons

author: RoGeorge
author_rank: Super Contributor
timestamp: August 22, 2024, 04:11:57 pm
content: 1080p from a moving rocket at 180km altitude seems not easy. Even assuming on the fly compression, that's a stream of at least a few Mbps.I would start by using Shannon–Hartley to estimate the needed power. Without plugging any numbers, my wild guess is the needed transmission power will have to be way bigger for the size of a DIY rocket. Saying this based on how hard used to be to receive back in the days a much narrower channel, analog TV, from 50-100 km away. Those TV towers were using a lot of power. I hope I'm wrong with this pessimistic estimation.Maybe use a commercial race-drone transmitter, but with a custom power amplifier, then a big dish antenna at ground, underneath the rocket.

author: yaxsomo
author_rank: Newbie
timestamp: August 22, 2024, 04:53:04 pm
content: If you see this product:https://www.multitronix.com/kate-3-transmitter.htmlIt can send telemetry up to a 100 miles and it’s not big at all.I don’t think it will radically change the size for video streaming

author: edavid
author_rank: Super Contributor
timestamp: August 22, 2024, 05:38:23 pm
content: Quote from: yaxsomo on August 22, 2024, 09:37:37 amQuote from: yaxsomo on August 22, 2024, 03:41:04 pmSo is it 180km or 4km? That's kind of a big difference

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2024, 06:25:58 pm
content: Apart from the transmission itself, I see two big problems:Very low temperature operation. You'll have to heat your equipment. Even at 12 km, outside temperature is around -70 deg. C.Transmission frequency shift due to the rocket moving away at high speed.Is this in your considerations?

author: yaxsomo
author_rank: Newbie
timestamp: August 22, 2024, 07:02:39 pm
content: Quote from: edavid on August 22, 2024, 05:38:23 pm180Km. The 4Km one it’s just one of our recurrent launches

author: yaxsomo
author_rank: Newbie
timestamp: August 22, 2024, 07:08:46 pm
content: Yes I’m taking into account the doppler effect and temperature concerns

author: Someone
author_rank: Super Contributor
timestamp: August 22, 2024, 11:58:09 pm
content: Quote from: yaxsomo on August 22, 2024, 07:08:46 pmHow?

author: Marco
author_rank: Super Contributor
timestamp: August 23, 2024, 09:38:01 am
content: Just see how far you can get with 5Ghz wifi and a drone tracker?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 24, 2024, 07:58:45 am
content: Thermal management is a huge problem for you, but it is due to the circuit operating in vacuum. With no air around it, no heat can be transferred to air. Fans don't work at all because they have no air to move.Also, in a vacuum, there is no temperature. You need to have something with mass before you can measure it's temperature. You can have huge thermal gradients between components that generate a bit of heat of their own, and components that don't. 180km is halfway towards orbit so have a look at the differences for designing electronics for space.

author: wasedadoc
author_rank: Super Contributor
timestamp: August 24, 2024, 08:32:19 am
content: Quote from: Doctorandus_P on August 24, 2024, 07:58:45 amThat is only 0.5% of the way to geosynchronous orbit.