Range Test - 2 Graupner Tx's to 2 GR-16's

WARNING THIS WAS A GROUND TEST ONLY. ​

​

FLIGHT TESTING MAY RESULT IN DIFFERENT BEHAVIOR.​

So since there has been so much discussion of using two Graupner Tx’s with one controlling the copter and the second one controlling the gimbal here’s a follow up test for that scenario. Here’s the results of an unscientific test.

Equipment
Graupner MC-32
MX-16 Copter recv. Mounted on the Modi-Fly Recv Rabbit

Graupner MX-20
MX-16 Radian control mounted on the roll cross arm

Iftron Mondo Extreme 1.5w tx. with a Bluebeam 3 lobe antenna mounted on boom 5 with the antenna pointing down
Iftron Yellowjacket Diversity Receiver with dual antenna, Bluebeam 4 lobe and 4 lobe FAN antenna.

Test location
Back deck of my house at an altitude of 5,120 feet. Copter was setting on the top of a steel mesh patio table. Boom 1 was pointing south. (Note: typically this type of setup would produce a ground plane for the antenna’s which would affect signal strength. This is not the same setup as yesterday’s test due to 25mph winds)



I planned on two test locations which can be seen on the Google Map View

1. Cul-de-sac at 920 feet – Below Height of Test Pad by 49 feet
2. Far point – 8,271 feet – Higher by 164 feet

All points were line of sight.



Results –

I had good signal for both the Graupner's and the Video. At the furthest point I had two signal bars on the Graupner. If I stepped behind my truck I lost the signal. Also the signal was best with the antenna in a vertical position. When in horizontal position I lost 1 bar.

I had complete control of the copter. I was able to do camera switching between the FPV and NEX7, trigger the NEX7 and do an MK calibration with the MC-32.

There were no issues with control of the copter (camera switching) or any issues with control of the camera with the MX-20.

930 feet - MC-32 top and MX-20 bottom - receiver data




8,271 feet - MC-32 top and MX-20 bottom - receiver data





Note: RX Strength on the MC-32 was a bit low at 15% but I think I was to close to my vehicle. As i walked around it was generally in the high 20% range.

Lessons learned

While I doubt that I will ever fly out to 1.57 miles it is reassuring to know that the setup is capable of doing that type of range. Graupner claims 4000m range with the Hott system. I was at 2,521m but ran out of places where I could test that distance and still be line of sight to the copter.

I would suspect that with motors running while in flight the range may be different with all of the other electrical equipment running.

Final Notes

This setup was with an MC-32 for the copter and an MX-20 for the gimbal operation. I have no way of knowing whether other combinations of transmitters will give the same results. As noted ​

WARNING THIS WAS A GROUND TEST ONLY. ​

FLIGHT TESTING MAY RESULT IN DIFFERENT BEHAVIOR.​

IT IS IN NO WAY A RECOMMENDATION ON HOW YOU​

SETUP YOUR COPTER.​

 

Andy bit hard to see in the photo of the rig but the MC-32 was talking to the GR-16 up on the Modi-Fly mast. The MX-20 was connected to the second GR-16 and looks like this, essentially a drooping angle but at about 90 degree separation. I just let them flop around.

Distance between the two is about 15 inches.





As to the telemetry the MC-32 was putting out both the MK info as well as the basic GR-16 stuff as shown in the photos. The MX-20 obviously only had the GR-16 data. I saw no difference in how everything seemed to working between the dual TX setup with individual receivers and a single TX driving 2 receivers together.

Of course that doesn't mean that different TX types and different GR types wouldn't have an issue but in this specific setup it looked fine.