Combining live telemetry data (915 MHz) and video (5.8 GHz) transmissions on a display for a 10km launch?

[beretta]

Hey everyone, I'm looking for some help for combing live telemetry (915 MHz) and video (5.8 GHz) on one display for a 10km supersonic launch. I currently have:

Telemetry TX:
- Eggtimer Quasar (915 MHz)

Video TX:
- Walksnail Avatar HD V2 TRX
- Avatar V2 1.9 dBi antenna

Ground side:
- Raspberry Pi 4 (Also have some spare Teensy 4.0s, could use computer with USB modem)
- 5.8 GHz antenna: Avatar V2 1.9dBi antenna, (probably will buy or DIY 7 turn helical instead for extra gain)
- 5.8 GHz receiver: Walksnail VRX (HDMI out only)
- 915 MHz antenna: omni or yagi
- 915 MHz receiver: RFM95 LoRa Transceiver Module

How I can receive both transmissions and put them on one display as a video overlay with telemetry info on it. I'm willing to use different equipment except for the camera. If anyone can provide knowledge on how that entire signal chain would work that would be awesome.

 

[cerving]

That 5.8 GHz video transmitter is probably not going to work at 10 km, it's only 100 mW. You need something with a lot more power, which will require a Ham license. Our telemetry transmitters work at that distance with 100 mW because they're a low data-rate transmitter... 9600 bps, vs. several Mbps for compressed video.

The data overlay is going to be challenging in real-time. There are some programs that will do it with video, but real-time is a different animal.

 

[beretta]

That 5.8 GHz video transmitter is probably not going to work at 10 km, it's only 100 mW. You need something with a lot more power, which will require a Ham license. Our telemetry transmitters work at that distance with 100 mW because they're a low data-rate transmitter... 9600 bps, vs. several Mbps for compressed video.

The data overlay is going to be challenging in real-time. There are some programs that will do it with video, but real-time is a different animal.

Its specs say FCC: <30dBm, does this not mean a max of 1000 mW? We were planning on using 500 mW of power. I attached a portion of the spec sheet below.

 

[ksaves2]

Plus......................One needs to make sure their "high powered" telemetry or camera electronics DON'T mess with their deployment devices. With a combo telemetry and deployment device, one doesn't have to worry as the work as already been done by the maker.

I lawn darted a couple of rockets and had one rocket blow the deployment charges on the pad before I realized what was happening. Taught me the necessity of ground testing with bare contained ematches for 30 to 60 minutes before I took the combination out to the launch site to fly.

I was also stupidly going to fly an 8 watt tracking transmitter until I got my Ham radio General license and had the mishaps above. Nixed that idea immediately.

Am able to get by with the lower powered stuff but generally if one is going for the "extreme" the 70cm ham band has a bit of an edge over 900Mhz.
I've flown plenty of the unlicensed 915 Mhz GPS stuff with Cris' trackers (from Cerving) above and never lost a sport rocket ever! Some of them flew and disappeared for quite a long time at altitude too! I liked to build electronics so had a good time. Low power GPS trackers work fine at altitude and have excellent range. It's that "last known position" that's needed for GPS tracking on recovery that's key to getting the rocket back.

I'm going to rant and rave one more time. If flying a separate tracker and deployment electronics for the first time, always, always, always ground test with contained ematches without BP of course on the altimeters. Turn on the Rf tracker, turn on the altimeter(s) and let it sit upright for 30 to 60 minutes or so. If the ematches don't blow nor the deployment devices shut down (stop beeping) am good to go fly at the launchsite next time

Ideally, it's best to mount a tracker in a nosecone bay if at all possible but if room is at a premium, can stick the tracker in the ebay, drill a hole in the front bulkhead and project the antenna into the parachute bay with a stiff plastic stent to support the wire. (Not a carbon fiber tube mind you!) And!! do the ground test. The plastic tube stent prevents the wire antenna from getting smashed down under acceleration in a parachute bay which will shorten the ground range. The cardboard tube that AT ships with their motor grains to contain the given igniter is good too and is disposable on deployment!

A tracker in the NC usually has an Rf blind spot right behind it to further prevent interference with the deployment electronics. Yeah I know not possible with smaller rockets but if one ground tests before flying, it will avoid a lot of grief and one has a chance to modify an installation before they have to dig the lawn dart out of the ground!!

Oh, I suggest using an external keychain camera of whatever resolution one wants and get it after recovery. Call it good. Live video serves no purpose except if one expects TO LOSE THE ROCKET! Kurt

 

[cerving]

I think live video would be really cool for very high altitude flights, such as the one that the OP is planning. You are definitely going to lose sight of the rocket, so having the video up on a big screen by the LCO would be awesome. Unfortunately, they're also the most challenging environment for the transmitters. AFAIK, nobody has ever done live video with anything beyond a garden variety model rocket.

 

[Art Upton]

I think live video would be really cool for very high altitude flights, such as the one that the OP is planning. You are definitely going to lose sight of the rocket, so having the video up on a big screen by the LCO would be awesome. Unfortunately, they're also the most challenging environment for the transmitters. AFAIK, nobody has ever done live video with anything beyond a garden variety model rocket.

I've done lots of Live video even with P rockets at the X-Prize cup in New Mexico Space port in 2007 before HD recording was an affordable option for rockets.

I recommend putting the patch antenna with about 3 or more db Gain pointed up about 25 feet away from the launch pad with the antenna horizontal to get best coverage. If the antenna is vertical inside the rocket for supersonic, you need to be far away from the pad and use a 7-10db Grid antenna and someone pointing it at the rocket as it travels.

I had used 1 by 2s to build a beam for the grid dishes to mount on, folks called that the Video Bazooka.

Here is the Redstone Team P motor Rocket. @troj and Greg created a mini bird house to mount the high power transmitter on the side of the rocket with the antenna sticking out horizontal.

 

[Art Upton]

Here is a tiny image from the wayback machine on the grid antenna with a pistol grip mounted forward on the 1x2 which went over the shoulder for balance. Receiver flat and behind antenna.


A pad receiver with the antenna pointed up with a camcorder in a lunch bag. You can have both an aimed antenna and pad antenna at the same time on Analog video. Not generally possible with digital link as it is point to point, not multi-point like Analog Amateur SHF TV this was.

 

[cls]

@beretta - bottom line, get your ham license! Open the door to lotsa fun. The Technician (basic) test is 35 questions, passing score is 28.

 

[cerving]

I've done lots of Live video even with P rockets at the X-Prize cup in New Mexico Space port in 2007 before HD recording was an affordable option for rockets.

I recommend putting the patch antenna with about 3 or more db Gain pointed up about 25 feet away from the launch pad with the antenna horizontal to get best coverage. If the antenna is vertical inside the rocket for supersonic, you need to be far away from the pad and use a 7-10db Grid antenna and someone pointing it at the rocket as it travels.

I had used 1 by 2s to build a beam for the grid dishes to mount on, folks called that the Video Bazooka.

Here is the Redstone Team P motor Rocket. @troj and Greg created a mini bird house to mount the high power transmitter on the side of the rocket with the antenna sticking out horizontal.

Cool, what kind of transmitter/receiver did you use?

 

[Art Upton]

Cool, what kind of transmitter/receiver did you use?

These were 2.4gz and I had 1.5 and 2 watt units using FM ATV type transmission.

The one in this video was 1.5 watts with a CCD camera looking down from inside the Bird House You needed a Ham license to use them.

That 2.4 does not work well today even at a far away rocket launch, everyone has a Wifi device on their belt or in a pocket. That is why the R/C FPV devices are using 5.8gz , also because 2.4 is being used to control their Airplane or Drone.

 

[OverTheTop]

Look up many of the flight computers that can be purchased for drones etc nowadays. Look for one with OSD, on screen display, functionality. Then you can end up with something like this:


A HD video feed with a data overlay. This is from my Vertical Trajectory System that I am getting going. Software on the flight computer is Ardupilot.
www.ardupilot.org

 

[schworer]

The other item you need to check is make sure the TX output doesn't interfere with the GPS as I've found this through personal experience. Even though the TX and GPS RX are on different frequencies, in close proximity harmonics and induced noise can swamp the GPS receiver. This is particularly the case when jacking up the TX power to get a better link margin. I solved the problems I was having through shielding, grounding, and increasing the distance between the TX and the GPS.

 

[Aeva]

Look up many of the flight computers that can be purchased for drones etc nowadays. Look for one with OSD, on screen display, functionality. Then you can end up with something like this:


A HD video feed with a data overlay. This is from my Vertical Trajectory System that I am getting going. Software on the flight computer is Ardupilot.
www.ardupilot.org

How are you using ardupilot for your flight computer? is it just for sensors? or did you add some active functions (eg, dual deployment? fin gyros?)

Just curious about your implementation.. I've come across ardupilot before but haven't dug into it.

 

[OverTheTop]

In your case you could use it just as a sensor suite for the video overlay. The video overlay is fully customizable. In my case I also use it to control four canards to keep the flight vertical.

Deployment is handled by regular flight computers (Telemega and Ravens) for reliability.

I also have mostly built an antenna tracker to keep the video and telemetry feeds on-veam for the receive antennas.

 

[OverTheTop]

FYI, managed to find a picture of my VTS assembly.




The attached PDF is far more readable than the above image .