R9M RSSI fluctuates from 48 - 100

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R9M RSSI fluctuates from 48 - 100

Post by dushan » Sun Dec 30, 2018 2:50 am

Dear All,

I've been flying X6R and X8R and thought of getting a long range module for my gliders.

Got the R9M (red) with Super 8 antenna for the module and dual T antennas for the receiver.

I had updated my Radio FW to opentx 2.1 or 2.2 ( can't remember the exact version) as I had to update my X8R and X6R FW sometime back.

So as usual I updated the R9M and R9 receiver to the latest stable FCC version (both updated sequentially as advised and I had the latest OpenTX FW already installed as advised)

I mounted the dual T receiver antennas on my glider one vertically and one horizontally on both sides of the plane. Also the vertical one comes of the plane from both ends so it does not getting blocked from the plane even when turning to guarantee maximum range/reception.

I've changed the R9M output power to 100 MW both from the TX and module switches. I checked and confirmed the 100MW setting as it had better range than 10 MW setting.

I range tested and flew fine. After checking my telemetry logs, it seems it is just performing like a normal X series receiver, but sometimes even worse. I fly the same pattern and altitude in the same place everyday and when turning sometimes my X series receivers' RSSI go down to 48/50 (although I mounted them 90 degrees apart as advised) at about 120 - 150m altitude but usually stays between 60 - 90. I got the R9M and R9 expecting a better range since I'm planning to do some FPV in the future, but it is preforming even worse.

I've seen many videos in Youtube range testing R9M and R9 but all most all of them are using quads and not planes/gliders. There was one video using a plane flying about 10km at 500mw and both his receiver antennas were vertical and parallel. He had normal dual antennas and not the upgraded dual T antennas like mine. Since they suggested Super 8 has better range, I got the Super 8 antenna as well. My module, module antenna, receiver and receiver antennas came in one bundle with upgraded antennas from the factory. I didn't upgrade them. Can it be that Super 8 is better for quads better than gliders as they relatively fly low but in various angles? Should I use an antenna like skinny 900 Mhz for planes/gliders for better range at high altitudes instead of more diversity? I'm sure something is wrong as some people fly even 5km at 10MW so 100MW surely be able to fly at higher RSSI withing 200m regardless of the interference.

Thank you in advance,


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Re: R9M RSSI fluctuates from 48 - 100

Post by jhsa » Sun Dec 30, 2018 12:32 pm

5Km at 10mW??? :O Doubt it..
Even at 100mW I don't think you would get there without signal dropping sometimes..
I might be wrong of course.. :)


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Re: R9M RSSI fluctuates from 48 - 100

Post by MikeB » Sun Dec 30, 2018 4:41 pm

I tested a R9M module and R9 receiver using the standard antennae. I had EU-LBT firmware running so operated at 10mW. I got simimar, although slightly better, RSSI values that I did using the same, fixed wing, aircraft with a XJT/S6R, and the S6R is usually better than a X6R/X8R.

I suspect your antennae may be more directional than the standard ones.

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