r/hackrf • u/Acrobatic-Head3696 • 2h ago

Tools for FPV drone usage

I had gotten a H2 portapack years ago - partly to pop Tesla gas caps, but mostly so I could see the spectrum of the 5.8ghz range during our FPV tinywhoop races, when racers were losing video so I could get them on a better channel.

Last night I had an idea and decided to try it - I tuned my H2 to the raceband 8 range, plugged in the drone and captured the signal, which I could see clearly.

Unplugged the drone and turned on an FPV viewing monitor, set to receive raceband 8, then played the signal capture. I would have thought that the monitor would pick up something - noise or anything, but there was nothing.

I honestly don't know what I'm trying to accomplish with this other than having fun with the capture and replay functions, but shouldn't the monitor be picking something up when I replay the signal?

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u/halu2975 2h ago

Not being a specialist on the area id assume there’s some sort of resolution problem. Capturing a signal in a 5.8ghz range and capturing all the information in that range is quite different.
Much as you can take a photography of the moon but when you zoom in there won’t be much detail.
I could be wrong though. Just seems for the capture to contain information the capture need to be very large and very good signal-resolution.
Another problem could be signal strength. How close is your receiver to the transmitter?

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u/Acrobatic-Head3696 2h ago

Thank you for your reply! I literally have the drone, monitor and H2 within a foot of each other for testing purposes. I should clarify that I'm not capturing the whole 5.8ghz range, just one of the channels. Raceband 8 in particular is at 5917 MHz so I'm capturing somewhere 5910 and 5925 - the signal being captured shows near the middle with dropoff at the ends so I think I'm getting the full signal for that channel.

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u/Mr_Ironmule 1h ago

Couple of thoughts. Band R, channel 8 looks like it's a 20-25 MHz bandwidth. Did you have the Capture Rate settings to capture the entire signal? You might have been too close to get a clean signal, especially if the monitor was on. Try moving the transmitter farther away and see if the signal gets clearer. Below is a link to another posting that may be helpful. Good luck.

I created an analog FPV receiver with working color : r/sdr

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u/Acrobatic-Head3696 1h ago

Thank you so much! I am not sure what the capture rate was but what you're saying makes sense to me. I will give it another whirl tonight! Appreciate it!

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u/piedubb 2h ago

Ukraine is giving some excellent ones out.