Someone with deeper tech knowledge needs to help us out with what happens if DSM2 signal is lost, or signal is lost on the park-flyer versions of receivers.
Some reading I have done have had people getting away - fast - from the OrangeRX park-flyer receivers to at least the R620x with satellites for diversity.
The fundamental change between DSM2 and DSMX is a DSMX RX/TX pair will roll to another channel if the link goes down. DSM2 picks a pair of links at power-up and stays with them. This would only affect it's resistance, but at an event with pilot registrations in the hundreds, that does become significant.
Diversity on the RX side will only help you if there's shadowing in your airframe -- if you can get the parts positioned such that a large RF-opaque part (battery, motor, carbon framing) can get between your RX antennas and TX for more than a split second, a satellite is a good thing to have regardless of the signal density. Noise on the band will make this worse, but burying your RX in a carbon frame or strapping it to the side of your monster-sized battery will limit your range at specific attitudes in an empty field.
Seems major events may need a spectrum analyzer to detect radio transmitter/receiver frequency interference, and FPV, as well.
I'd partially agree with this, but a good spectrum analyzer is a pricey piece of equipment. Add to that the sampling may need to be made at many points at both polarization (in fairness, this means setting the antenna on it's side and re-running the measurement) . . . and if the offending noise source is intermittent in nature, there's a GREAT chance you'll miss it, but the pilots won't.
There's also the issue of fixing the offender -- if they're over the line, the next step is to either ask nicely (if you lived next to an empty field that a large noisy crowd is gathering in and one of the trouble making organizers came to your home and asked you to turn off your internet for a few days, would you be accommodating?) or call the FCC (the correct solution, but the chance they'd not get to it in time, not find the problem, or make the situation worse is very probable).
I noticed some are proposing banning older gear outright on the flightline. Some shows like Nall have done something similar, but in a specifically identifiable way -- 2.4GHz only. Picking and choosing among the 2.4GHz protocols as approved or not approved (particularly using an EU standard in the US) is a non-starter.
Doing so would require the flightline approval of every RX/TX pair -- it's easy to spot a 72MHz radio and say "no", but inspections would require not only examining the TX *AND* RX, but also checking the bind was in the correct mode. It would also require banning gear lacking proper marking that might be good, might not -- hard to say what goes in some of those cheaper Chinese radios. On top of it all, it would still allow low power versions of radios with good protocols that might be resilient to the noise, but would be inappropriate to the pattern.
Frequency control boards were a way of life at any event because of the certainty of lock-out that came with the 72 MHz radios on overlapping channels. We're seeing it now on FPV-friendly events, for the same reason -- the guy playing with his VTX in his tent can shoot down a pilot in the field. They also don't prevent the use of certain gear, only time limited it to de-conflict -- there's a big difference between telling someone they can't fly until Joe has returned the peg and telling them they can't fly at all.
Old and lower standard 2.4 radio pairs do carry a higher risk of loosing control in denser environments, but the chance is far enough from certain to warrant the intrusive inspections required by such an outright ban.
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