I spent the 23rd and 24th of September running 7 submarines with 7 different radios.
The venue was the Fly Casting Ponds at the Golden Gate Park in San Francisco CA.
It is a cement "pond", with angled sides, 180' x 120', and about 4' deep.
The radios tested were:
TBS Tango 2
Frsky Tandem XE
The Radiomaster radios were used with ExpressLRS trasmitter modules, either Nano or Micro size, running at 250mw, with dynamic power on, and with 100hz, std telemetry, and wide switch mode. firmware version is 3.3.0. all Radiomaster radios were running EdgeTX version 2.9.0. I used both a Happymodel TX module, and two different BetaFPV (nano and micro) transmitter modules.
The Jumper T-20 was also running the same version of EdgeTX, a branch of OpenTX, and the same version and configuration of ExpressLRS firmware on its internal RF deck.
The TBS Tango 2 is using its own "FreedomTX", a branch of OpenTX, and has its own built-in TBS crossfire RF deck, running at 250mw dynamic on, max power.
The QX7 is running OpenTX version 2.3.15, and was used with ExpressLRS micro tx module, TBS Crossfire micro tx module, and an FrSky access r9m module.
The Tandem XE uses its own Etheos firmware, and has a built-in r9m access rf deck.
The Submarines were as follows:
a 1/8 scale Norbert Bruggen Delta research submersible
a 1/96 scale Skipjack class USN nuclear fast attack submarine
a 1/96 scale Blueback class USN diesel electric submarine
a 1/35 bronco Type XXIII german ww2 u-boat, using an R&R model engineering wtc.
a 1/32 scale "Proteus" 16" long submarine from the movie "Fantastic Voyage"
a 1/32 scale "Nautilus" from the disney movie "20,000 Leagues under the Sea"
a 1/32 scale "Flying Sub" from the movie "Voyage to the Bottom of the Sea"
The receivers used were as follows:
TBS Crossfire 6ch PWM Nano RX
BetaFPV ExpressLRS Nano RX w/ Matek 6 channel PWM adapter
BetaFPV ExpressLRS Nano RX w/ Matek 8 channel PWM adapter
Happymodel ExpressLRS EPW6 PWM RX
Frsky R9 sx six channel PWM RX
There really is nothing odd to report here. Of the 10 gentlemen and 29 submarines that were brought, myself and one other gentleman were using 915mhz. The other 915mhz equipment was an FrSky horus x10s express, with an r9m module, and a r9 sx receiver (identical to what i used in the QX7).
Neither of us had any issues. I tested the ExpressLRS, TBS Crossfire, and R9 systems in the same submarine (The Proteus) because it was easily configurable/modifiable, and could be easily seen anywhere in the pond.
The Testing consisted of running the submarine in a tight figure 8 circle about 20 feet from the northwest corner of the pond, at a depth of 2 feet, with me walking backwards away from the submarine, toward the south end of the pond, until the "Telemetry Lost" notification was emitted by the transmitter (the 180' length of the pond). I had a spotter watching the submarine at the north end of the pond, verifying that it was still under control.
IN ALL CASES, I lost sight of the submarine before i heard any "Telemetry Lost" notifications.
The only difference between configurations was that which differed between protocols.
there is no way to set dynamic power on the FrSky system, so it was set to 250mw.
there is no way to set telemetry packet ration in FrSky or TBS, but i did have telemetry turned on in all cases, and i also had "vbatt" telemetry, and "Cells" telemetry available on the ExperssLRS and R9 receivers.