I clipped the tip off of one of the two diversity ELRS antennas on my 6" freestyle rig. It happens to be off the Mateksys R24-D, which is shipped with antennas that have a chunky thing at the end of the antenna. Hard to find replacements for those if I want the exact one. Can I just use one of my old FrSky 2.4gHz antennas I have laying around? It doesn't have the awkward chunky thing on the end and the length of the exposed wire is different.

Also, how important is it for the 2 diversity antennas to match?

When I was replacing the rxsr / xm+ antennas they came in different length exposed elements. I was also playing with a Emax d-8 rx.. I read research on %s, wave lengths ect.. and got lots of “opinions”.
PropsOFF FPV suggested I tried 32.8mm(if I remember correctly)..stated .”guys flying “other lengths” were dropping out, and we (32.8mm) were still going”…
Not sure if it was just a Frsky d8 thing or if it was a 2.4ghz thing.. but I have a ELRS antenna needing replacement .. I’m starting at 32.8 mm. (If that is the length )
And YES! My d8 rx out flew the 400mw vtx In clear line of site..

Any 2.4GHz antenna will work fine as long as the connector is correct. I believe the XM+ receivers used non-standard IPEX4 connectors, but other FrSky receivers used IPEX1/u.fl antennas which should be compatible.

The antennas included with the Matek R24D are called sleeved dipoles. We did some antenna testing here: https://docs.google.com/spreadsheets/d/1...edit#gid=0

Regarding the optimal length, an ideal 1/4-wavelength 2.4GHz antenna should be ~31.2mm. In practice, however, this needs to be adjusted based on the velocity factor of the wire/coax being used which makes the actual length a bit shorter. Most 2.4GHz FPV antennas will have an active element ~28-30mm. Without a VNA you're not going to be able to tune it exactly, so I would just stick with that approximation.

Awesome data! Thanks!

Looks like the best antennas have to be ordered from Poland??

The prodrone.pl antennas are excellent, but the takeaway should be that almost all of the tested antennas are plenty good enough.