After flying the FrSky R9 and Crossfire systems for the past several years, got used to the antennas (both T style and standard).  Received my BetaFPV 915 ELRS Nano today...and the antenna is TINY!  I figure it is likely just me being "set in my ways"...but whoa!  This thing will be perfect for a micro build!







Excited to try this out and see if my old R9 is still relevant

BetaFPV do two sizes of antennas for the 900MHz system. 46mm ones like what you have and 80mm ones which are closer to the Crossfire Immortal T.

The 46mm ones are likely similar to the TBS Minimortal T antennas that you can get for Crossfire in that they don't have particularly great range and TBS actually tell people not to use a Minimortal T unless it is for close proximity flying. So it will be interesting to find out how well those 46mm ones you have perform. If you crank the power right up they might still be usable for longer range flying but I would be a bit cautious until you have tested them. It would probably be sensible to have a GPS module installed with GPS Rescue / Return To Home configured.

Trying to figure out which quad this will get installed on. Guess I could install it on The Bug and get rid of one of the few FrSky RX's I have left. It is a relatively short range affair with the limited pack weight that it has. Was just really surprised, thank you for the info. Thought maybe they packed a 2.4 antenna into the bag on accident.

Wish they had used an IPEX4 like the R9 and Crossfire systems...but nooooooo, they had to be all old fashioned 

https://www.expresslrs.org/1.0/quick-start/tx-r9m/
i dont know if there are a lot benefits, but you could get 900mhz elrs with your actual r9 gear :-)

Successfully installed on the Japalura.  Took a bit to flash it after compiling the firmware.  Slotted it right into where the Crossfire RX was.



So the TX is set at 10mw...was able to get out to about 150 meters and the LQ never dropped below 5:95 and I was happy with that result.  The little antenna holds its own.  With a little more power, I bet this will rival my Crossfire.

(12-Jan-2022, 12:53 AM)hugnosed_bat Wrote: https://www.expresslrs.org/1.0/quick-start/tx-r9m/
i dont know if there are a lot benefits, but you could get 900mhz elrs with your actual r9 gear :-)

This is what I did.  I had my old 2018 R9M collecting dust so I flashed it with ELRS.  When I went to flash my sole remaining R9 Slim+, I found it to be dead so I ordered the BetaFPV 915 for my testing.

A few more flight with TX locked at 10mw, sitting on my patio that is an RF nightmare, 125m had the LQ flashing that the connection was getting low.  It was still flying solid.  This is with the small antenna and is about the same result I get from my Crossfire link at 10mw with the full size ImmortalT.

Funny thing, I can sit on my couch in my living room and get out to nearly 200m before I start to get warnings about link degradation with the same settings.

I would imagine that 250mw is going to be my standard power for most of my flying.  I can fly to the Post Office which is just shy of a kilometer at 250mw and it is locked at 100 for either ELRS or Crossfire.  Doubt I will be leaving my Crossfire behind any time soon, but the results are certainly acceptable for most of my local flying.  When I push out to multiple kilometers using my fixed wings, I usually bump up to 500mw just to be sure the link stays solid and to overcome weak interference signals that may be present.

The Japalura is a thirsty beast regardless of how gentle I fly it, so it is not a good test for range...might pick up another ELRS receiver and mount it on something that gives me 10+ minutes of flight for some further testing.

Ordered a second RX, but this one is the HappyModel ES900RX and I am curious to see how it compares to the BetaFPV RX. The HappyModel is even smaller, not sure which craft gets it.

I have been flying at 115k as the R9 module still needs to be modded...a pack of resistors is due today or tomorrow so I can get the higher baud rate running. Having the un-modded module has not caused any issues other than the script runs a little slow. No lockups or errors.