[greggold]

This flight log is from the Slick, a 90cm span 3d plane, with a matek R24 P6 rx and a Radiomaster T16 tx with an elrs internal module. All the flight data appears in one plot because I adjust each data item. Measurements are taken every 0.5 sec. The main things of interest are the blue RSS (receiver signal strength), running between -30 and -45 (which means -60 and -90, a normal range), the red receiver quality (RQly) running at 100% except for a few dips below 90%, and the pink receiver signal to noise (RSNR). 

At 50 sec into the flight, multiple events occur:
- a blender manoeuvre enters its vertical dive and spin
- the throttle (THR) at 50 sec went from full throttle (10) to zero (-15) which caused the plane to flip from vertical climb to vertical dive
- the RSNR fell to 0 for less than half a second
- the transmitter power (TPWR) briefly increased from 10 mw to 25 mw
-the RQly fell to 84% and the RSS dipped slightly below -90.

The TPWR increased because the elrs was set to "dynamic power" whereby if the rx perceives a signal problem, it increases the tx signal power from 10 mw to 25 mw as happened here, or 50 mw or 100 mw if 25 does not do the job. The decision to boost tx power is based on the RQly (the same as valid frame rate) which measures the percentage of packets of data that are valid, and also the RSNR.
https://www.expresslrs.org/software/dyna...mit-power/

It appears the main cause of the TPWR jump was the transient drop of RSNR to zero, at a critical point in the blender. The RQly and RSS also fell, but not to an abnormal level.
Why did the RSNR fall? I have several planes using R24 P6 rxs, and I only get significant RSNR falls when doing the blender manoeuvre, and only in around 20% of flights. One theory is my use of a sudden cut from full- to zero throttle to flip the plane (from vertical climb to vertical dive) causes a transient interference. A fall in rx voltage is ruled out as a cause.

The tx power jump demonstrates the elrs doing its job to maintain a safe signal, and no control loss was experienced. Matek rxs require the user to solder the pwm  pins to the rx circuit board, and in future I am likely to move to Radiomaster elrs rxs. I was a bit disappointed with the RM ER5A rx, and I hope the soon-to-arrive RM ER6 series of pwm rxs will be an improvement.

[caffeine]

Again you have some interesting stuff going on!

I read recently that the dynamic power mechanism may not be 'fully enabled' if you don't have channel 5 at 100% (the 'ARM' signal)

Dynamic Power uses the ARM state to determine what to do when telemetry packets are missed. If armed, then each missed telemetry packet after the first raise the power one level. If the connection is lost entirely, it will raise the power all the way up. If CH5 is always high, your TX will always run full power when no receiver is connected (when there is no telemetry received technically). If CH5 is always low, your TX will never raise power due to missing telemetry but will still raise power when the telemetry reports the signal is low.

You could also perhaps try a filter of some sort on the power input to the receiver (using a resistor-capacitor filter for example)

You mention that the Rx voltage telemetry shows no issues, however telemetry is a pretty coarse time base so it might be doing all sorts of transient stuff at a faster speed than telemetry can report.

[greggold]

Again you have some interesting stuff going on!

I read recently that the dynamic power mechanism may not be 'fully enabled' if you don't have channel 5 at 100% (the 'ARM' signal)

Dynamic Power uses the ARM state to determine what to do when telemetry packets are missed. If armed, then each missed telemetry packet after the first raise the power one level. If the connection is lost entirely, it will raise the power all the way up. If CH5 is always high, your TX will always run full power when no receiver is connected (when there is no telemetry received technically). If CH5 is always low, your TX will never raise power due to missing telemetry but will still raise power when the telemetry reports the signal is low.

You could also perhaps try a filter of some sort on the power input to the receiver (using a resistor-capacitor filter for example)

You mention that the Rx voltage telemetry shows no issues, however telemetry is a pretty coarse time base so it might be doing all sorts of transient stuff at a faster speed than telemetry can report.

I have not tried to modify Ch 5 in any way. At the suggestion of Andrew Newton, I know some fliers assign (in mixer) Ch5 to a switch that they use for throttle disarm, with 2 positions 100 and -100 (or 150 and -150). I test my planes have a failsafe by holding them in position, applying 1/3 throttle, and turning off the tx. So I assume that the throttle automatically disarms when signal is lost. I am critical of the documentation which makes a fuss how important it is to use ch 5 for arming and disarming, but not specifying the method to do this. 

If I go to Mixer, and select ch 5, and edit, there are many items to adjust:
The second item "source" I leave blank (---)
weight is 100%
I see trim is on
the eighth item is switch.

Do you set the second item "source" to a switch?

[srl]

Hi Greg and members.

To clarify for those new to ELRS.
I believe that Ch5 disarm is for flight controllers in multi rotors and dos-not apply to our fixed wing PWM servo setups.

Our PWM disarm on all transmitters is done direct to the throttle channel , we don't want all channels off!
All members should have the throttle disarmed when connecting a battery.

I haven't touched ch5 on my matek rx’s and looking at the logs dynamic power has been working fine.

srl

[caffeine]

Likewise I don't do anything with Ch5 and my dynamic power appears to work well also.

i may try assigning it to my throttle cut switch (SF) and set it to turn to +100 when I enable the throttle and -100 when I disable it, just as an experiement.

[greggold]

re
"i may try assigning it to my throttle cut switch (SF) and set it to turn to +100 when I enable the throttle and -100 when I disable it, just as an experiement."

I agree this would be interesting. But I am not clear what you plan to do.
Do you mean set mixes/ch5/edit/ the eighth item "switch"/ to your throttle switch. Will you change any other parameter in mixes/ch5/edit/ ? or any other parameter in another model menu?

re "I read recently that the dynamic power mechanism may not be 'fully enabled' if you don't have channel 5 at 100% (the 'ARM' signal)"
Do you recall where you saw this? If true it would certainly be significant.
I am still unclear how "channel 5 at 100% (the 'ARM' signal)" would be set, I am afraid I need directions how to set this, including whether both the tx and rx settings would need adjustment. My problem is there is no "ARM signal" in any menu that I can find.

[caffeine]

re "I read recently that the dynamic power mechanism may not be 'fully enabled' if you don't have channel 5 at 100% (the 'ARM' signal)"
Do you recall where you saw this? If true it would certainly be significant.

This post on RCGroups from one of the developers:

https://www.rcgroups.com/forums/showpost.php?p=51098433&postcount=2005

Regarding the Ch5 setup, I haven't tried it yet. When I do I'll note down how I do it.

[srl]

I've done a range test walk down the street with a RX. The TX log shows that it went from 25mw to 100 before the RX went into fail safe. I was happy that all was working well. It had good range too.

srl

[greggold]

I've done a range test walk down the street with a RX. The TX log shows that it went from 25mw to 100 before the RX went into fail safe. I was happy that all was working well. It had  good range too.

srl

I have done about 90 logs over the last month, and my impression is that dynamic power is working correctly with quite a few examples of its operation.

However in my channel monitor, ch 5 shows nothing.
I have looked at some vids, I think Painless360 has the best account of how you can have arming stay at -100 by default, and when you move your selected arming switch (or switches - 2 switch arming is popular) arming moves to +100. ch 5 is set up so there are only these two positions.

https://www.youtube.com/watch?v=r7GxIlPV1Xc

Is it possible that not setting the arming channel (so for example it shows in channel monitor) causes a problem for dynamic power?  I doubt this as if it did I think a problem would have shown itself in my logs by now. But I  am now clear how I can set the arming correctly and also I can review the arming status of ch5 in the channel monitor.

At the moment I use switch SA to operate a special function that overrides ch3 (throttle) and sets it to zero (-100) to disarm the throttle which I currently use whenever the lipo is plugged in and the model is not in the air.  I can use the Painless vid to set ch 5 to a default  value of zero arming (-100) and use SA to override the default and set arming to +100 (fully armed) when ready to launch.

Liam thanks for the reference on dynamic power, which I have not looked at yet. I know that in the T16 the base tx power is 10 mw, but in the T12 and Boxer it is 25 mw, and I am wondering why this is the case.

[caffeine]

Is it possible that not setting the arming channel (so for example it shows in channel monitor) causes a problem for dynamic power?

From my understanding, it seems that 'arming' through sending channel 5 high allows the dynamic power mode to use more stimuli, so there's no harm in leaving it low, but you can get more responsive dynamic power by setting it high

[caffeine]

I have just configured one of my models to try out the setting of channel 5 based on my SF switch (left shoulder, used for throttle cut on my radio)

I just configured 2 special functions to override the Ch5 value based on the switch position.

'Disarmed' / Throttle Cut

       

'Armed' / Throttle Active

       

[greggold]

that is useful, thanks.

I have done a post in RCG this morning (in "Official EdgeTX Discussion Thread") to ask about whether using a switch for ch 5 arming can influence the dynamic power function. I got a very useful reply from an expert Mike Shellim, who has written extensively on setting up complex models, and who referred me to this site

https://rc-soar.blogspot.com/2023/06/rev...-er6g.html

scroll down to the "The Channel 5 conundrum”, it is well worth a look.

There is a detailed description of options for dealing with ch 5 arming, and he agrees with those who say you should set ch5 yourself with a switch and not leave its values to chance.

In my T16 logs, I find the base TPWR is 10 mw, and occasionally I see jumps to 25, or to 50, or to 100 mw which I interpret as dyn pwr working as expected.
In my T12 logs I find the base TPWR is 25 mw, and very occasionally I see jumps to 50, or to 100 mw but they occur more rarely.
I would like to be able to set the base TPWR to 25 mw on the T16 while leaving dyn pwr on, but I cannot see how that is possible. I plan to study my logs collection to see whether 25 mw base TPWR is associated with a higher overall value of RSNR, compared to 10 mw.

[Florian]

I use EdgeTX special functions channel override set on a 2 way switch to arm/ disarm channel 5. See included attachment. 

When plugging in the lipo the ESC chime does not complete its usual beep routine until channel 5 is set to "armed". Note the throttle cut is also setup the same way on the same switch

Florian

[greggold]

More dyn power in action. As a sequel to the above data log, here is an earlier flight of the slick plane where dyn power jumps from 10 mw, to 25, to 50, and to 100, all in the period of 20 seconds. A blender appears to have triggered the 100 jump, indicated by the throttle cut at 40 sec. The initial jump around 32 sec occurred during full throttle on a vertical climb. A zoom picture is also attached.

[srl]

Hi Greg

A few times I remember my FRsky X6R with Horus10x having a very brief LOS at the recovery of a inverted spin.
All fine now since changing to PCB RX antennas and a Taranis 2019.
srl

[greggold]

Hi Greg
A few times I remember my FRsky X6R with Horus10x having a very brief LOS at the recovery of a inverted spin. 
All fine now since changing to PCB RX antennas and a Taranis 2019.
srl

I was thinking spinning was somehow causing a signal problem, but the more logs I look at seem to make full throttle look a more likely culprit. Note in my Slick logs there is no suggestion of loss of signal, just the tx power jumps, and an indication that there was reduced signal to noise. In the Jun 6 log at 153 sec there is a reduction in RSNR to 6 (from 10), and this corresponds with use of high throttle at that point.  But the esc is nowhere near the rx, so could the esc generate some interference?  I am confident the slick has no radio signal problem, the radio performance is nominal.

The other point is that the dyn pwr jumps are infrequent, and only occur when I am performing blenders or similar. I am continuing to collect and review logs and will try to define the frequency of dyn pwr jumps. I know they are rarer in my T12 tx (which has a base power of 25 mw) than in my T16 tx (base power 10). I would like to set the T16 base power to 25, but that would mean turning dyn power off (AFAIK). In some of his gliders Mike Shellim turns off dyn pwr and sets tx pwr to 50 mw.

However my T16 (with dyn pwr on and base power 10mw) has not lost signal in any (of the some 90) recent log flights.

I had a signal loss in my Frsky Tandem and an R10 rx, which I  discussed on RCG in the "FrSky - X20, X20S, X20HD, X20 Pro Tandem - 24 Channels with ETHOS"  thread in posts (#24717, #24738, #24760) about a data log in my CrackYak plane, and subsequent responses by Landru (#24746) and some others. I only discovered the signal loss when I studied the logs, but subsequently I experienced a transient loss in a blender. Any signal loss shows clearly on the logs. The cause here was bad orientation of the two 2.4ghz antennas (which I learned are sleeve dipole antennas; I clearly do not understand antennas well) and one 900mhz antenna on the R10 rx. After adjusting the antennas - in line with some good advice - there has been no problem and the logs are now clear. This example shows how logging can help model setup and antenna installation.

[url=https://www.rcgroups.com/forums/showthread.php?3703807-FrSky-X20-X20S-X20HD-X20-Pro-Tandem-24-Channels-with-ETHOS][/url]

btw I do not know the story on PCB antennas. The single antenna and dual antenna matek elrs rxs I mostly use have sleeve dipole antennas.