Airborne Crossband Repeat Experiment

This week me and a friend got together out of boredom and decided we'd try airborne crossband repeat. What the hell is that I hear you ask! Well we simply attached a Wouxun KG-UV8D handheld to a DJI Phantom 3 drone and sent it up. The Wouxun was in crossband repeat mode with a UHF frequency on the A VFO and a VHF frequency on the B VFO. We each had a Baofeng GT-3 handheld, one on VHF and one on UHF and spoke to eachother crossband through the Wouxun.

I attached the Wouxun in a holster to the skids of my DJI Phantom with cable ties and to my surprise it held steady and didn't really affect the flying characteristics of the drone although the battery didn't last as long due to the added weight.

The Wouxun was set to low power (around 2w) and I put on a stubby antenna to limit the intereference it may have possibly caused the drone. Luckily it didn't cause any interference.

With everything set, we sent the drone up and followed it up with another one for some air to air shots which look quite impressive in the video. We didn't get as close as we'd like due to quite a strong wind which made it dangerous to approach any further.

I set the drone to 45m and the beauty of DJI Phantoms is that if you let go of the controls, they stay exactly where they are due to GPS. This meant the drone hovered at 45m above my head whilst I operated the radio. The onboard camera allowed me to see the radio and check it hadn't fallen out!

My friend was 6 miles to the north of me and was unreadable when we tried to contact eachother radio to radio. We switched to the frequency the Wouxun was on and received eachother loud and clear. Much to my delight a friend of ours 10 miles to the east also heard us and was kind enough to record some video.

We spoke for just over a minute with no breakup and called it a day. All in all a success and just shows what can be achieved in an emergency situation.

Just some points to note:

• I'm fully aware of the amateur radio licensing conditions. This was a test that lasted just over a minute and we do not intend to repeat it.
• I am aware that you probably shouldn't attach stuff to a DJI Phantom.
• The two Baofeng radios were transmitting simplex only. No duplex, offset, shift or CTCSS.
• The frequencies we operated on were legal frequencies.
• I am aware that the same result could have been achieved on a hilltop or with a larger antenna.
• The 70cm frequencies you see on both radios are on the B VFO as a seperate channel and were not the frequencies we transmitted on. The frequencies you see as numbers are local AllStar links. We were transmitting on the A VFO which were named UHF RPT and VHF RPT.

No comments from radio police please, just enjoy the hobby and experiment as much as possible. 

Thanks for reading,

Lewis
M3HHY