Installing ezUHF – Antenna improvements

So, after writing part 2 of the ezUHF installation blogposts, I brought the F550 out to find out if removing the UBEC and placing a ferrite core on the SBUS cable from RX to the Naza brought me the improvement i was hoping for. Last wednesday I finally found the time to test it out. The result? Failsafe at around 750m with ezUHF JR module on low (150mW) and 1100m with the TX on high setting. Definitely an improvement, but still not the range i’m hoping for. Because i’m running out of ideas to lower the noise floor, i decided to mod the RX antenna and swap the TX antenna.

In several forums around the web ImmersionRC support team advises to either mod the standard RX antenna, of buy a dipole antenna. Running an dipole antenna should help the RX to lower the baseline and lower the incoming noise. This is the first mod I did.

I grabbed a piece of solid core installation wire, cut it to 165mm and soldered it right on the SMA connector of the monopole RX antenna.

Not my photo… will update to my own photo soon!

Running the analyzer again, i learned the full config noisefloor is now 3dBm lower, so this little 5 minute mod on the antenna provided significant improvement!
The first graph below is without the dipole, full config, the second one is with the dipole.

Stock antenna – Full config

DIY Dipole – Full config

To upgrade the TX antenna, i ordered an Diamond SRH-771  (Gain: 2.15 – 3.0db).

Last friday I put the config to the test, and…….. I chickened out @ 1800m with the ezUHF JR Module set to LOW!
For now, I am very happy with the improvement. Flying such a distance is something I will likely never do when i’m out to film, so more range is simply not necessary for me.

Moving to ezUHF was needed for me because of the poor performance of the FrSKY Taranis combined with 1,3Ghz video. I now have good range and all the good that comes with the OpenTX firmware on the FrSky Taranis, because setting up the transmitter, is a real joy with openTX!

I will do another test some day, when there is absolutely no wind, and see if i have the balls to go further… I might just build another multicopter just so see how much range I can get… it’s becoming sort of an addiction to get further and further….