sudden dive

[erhard52]

Let's say you are using the same transmitter that has an output power of 100mw EIRP with 2 different receivers - one has a sensitivity of  -92dBi and the other receiver has -98dBi of sensitivity.  If you get 1000 feet of range out of the receiver with -92dBi of sensitivity you will get 2000 feet of range out of the receiver with -98dBi of sensitivity.  You can also get 2000 feet of range with the receiver having -92dBi of sensitivity if you make the transmitter's output power 400mw (4x the power).  The FCC does not allow that high of power though because there is no way possible to pass spurious emissions and peak power limits.  The only way to increase range is to have very sensitive receivers.

You are using a different transmitter with the Spektrum setup. This could be something as simple as a pot that is dirty, which can cause exactly what you describe.

by "pot" you mean the pot in the servo?. if that were the case it should be RC system independent right? which it is not.
i understand your above description. RF power ideally drops of with 1/distance^2

here one more set of data.

i compare evo and dx6i transmitter at same distance (1m) from tinySA.
the lower trace is the background  ii captured with transmitters OFF over 5min in peak hold mode
1. this picture is evo turned on . we see hop interval is 5 MHz
average peak about -30dBm
https://photos.app.goo.gl/xdMemtz2HTrYksWEA

2. this is DX6i
hop interval about 2.5MHz and average peak about -22dBm, so a 8 dBm difference which is 6.3x in output power. DX6i has 200mW in the US that would mean evo is only outputting 31mW.

what is the output power of the module at level 5? 
can i use the XDP to program the XPS transmitter module? 

do you agree with my conclusions?

i will get an XDP in a few days - found one on RCGROUPS

thanks
erhard

thanks
erhard
https://photos.app.goo.gl/otwd6SNsEw9RN6jJ6


AI says (which then could only come from higher receiver sensitivity, right)

The XtremeLink® system stands out among RF systems in terms of range and reliability due to several key features:

Comparison of Range
XtremeLink®: Offers a range of up to 5 miles in line-of-sight conditions, significantly outperforming other systems like Spektrum DSM (~1000 feet) and Futaba FASST (line-of-sight range unspecified).

The extended range is achieved through advanced frequency-hopping technology and optimized RF design, ensuring robust communication even in challenging environments