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Over the last mounth we have had three crashes two with the old 8 channel rx with the hard plastic antenna and on the sailplane rx. So far the nano's and the rfu's are good. Is there a way to set the telemetry station to read the rssi that the reciever is see? Maybe missed frames all three were complete lockout 2 to 3 seconds to impact with terrafirma. Up untill this year we have never had a problem while the spektrum guys droping airplane frequently due to lockout. I have a RF Explrer hand held spectrum analyser most of the the time we see -90 to - 70 dbm in signal strength with frequent spikes into the -30 dbm range.
thanks for your time.
don king
i did look to find instructions for the telemetry station but could not locate them.
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Here is the original info:
https://www.xtremepowersystems.net/Old/ts.php
Are you talking about measuring the ambient signal levels in your flying environment? The lower the value, the higher the level of interference. If you ever see anything in the -40 dBm and lower range (like -30 dBm) then you should NOT fly! THAT is an unusable environment! Really anything in the -50 dBm range is questionable.
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yes i was speaking of the -dbm. the ambient level is around -80 with spikes in the -70 dbm range and occasional ones in the -30 dbm range.
so is there a reason that the double antenna rxs are not having a problem? Just lucky so far?
thanks don
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-30dBm across the entire band would be wiping out everything from operating during the period that signal was present. If that signal was only on part of the band (there would have to be some substantial bleed-over at that power level) then you could still fly when using a system that uses frequency hopping. The amount of power to reach -30dBm is staggering. Consider this: it takes 4 times the amount of power to double the effective range. So, if you can reach 1000 feet at 100mw it takes 400mw to reach 2000 feet. 6dBm doubles the range in receiver sensitivity. This is why it's always better to have higher sensitivity than output power with any radio system. The signal strength at 1000 feet with a 100mw system (like our XtremeLink system) should be in the -55dBm range. It can take hundreds of watts of power to get into the -30dBm range from any long distance. This is entirely possible if you are nearby a Nexrad weather station "ball". You need be at least 1.2 miles away from a Nexrad facility to even be able to turn on and connect your R/C system, and you shouldn't fly within 5 miles of one because of the very issue you are talking about. You might check the Nexrad installation map to see if you are affected:
https://www.ncei.noaa.gov/maps/radar/
Here is some info on them:
https://en.wikipedia.org/wiki/NEXRAD
This is the coverage map at 3000' AGL. These things have 750KW of power at 2.7GHz-3.0GHz (which bleeds into the 2.4GHz band).
Other possible sources for interference are TV repeater stations, directed WiFi towers, and even neighborhood or public WiFi towers.
The Nano receivers have a single antenna... the two pieces of wire are not two antennas.. that is actually just one antenna. The RFU has two independent antennas.
