SP-FLVS causing radio interference?

Hardware help and support for the FrSky Taranis
Post Reply
pmullen503
Posts: 232
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

SP-FLVS causing radio interference?

Post by pmullen503 » Tue Aug 14, 2018 3:46 pm

I added a SP-FLVS lipo sensor to a plane and got several "RSSI Low" and "RSSI Critical" warnings during a flight. Since this plane has been flying for two years without problems and the only thing that changed was the addition of SP-FLVS I removed it and flew it again with no problems. Checking the logs I found that with the SP-FLVS my RSSI was 10-15 db lower than the flight immediately after without it.

This is the first time I've used a SP-FLVS sensor. Has anyone seen this behavior before?

Rec. is a two year old X8R. I running opentx 2.0.20 on original Taranis X9D (not a plus).

I noticed my RTC would reset to 2010-01-01 whenever I turned the TX off. I replaced the battery and it seems to be working properly now but I haven't flown it yet.

Richard
Posts: 169
Joined: Sat Mar 29, 2014 10:44 pm
Country: United States
Location: Coral Springs, FL

Re: SP-FLVS causing radio interference?

Post by Richard » Sat Aug 25, 2018 2:14 pm

I have been using your config, including the X8R 5 years old, and V 2.0.0 and never had that kind of problem, but I did experience low RSSI, and re-charging the TX batt solved the problem. (I use a LiFe 3S for the X9D TX).
However, keep an eye on the sensor, and install it not too close to the RX. Any electronic device causes EMI. However the RX signal, can be garbled, but not lowered, unless the sensor takes too much current that your BEC cannot deliver (Faulty sensor, in this case)
Richard

User avatar
bob195558
Posts: 1901
Joined: Sun Dec 16, 2012 7:24 pm
Country: United States
Location: New England, Vermont
Contact:

Re: SP-FLVS causing radio interference?

Post by bob195558 » Sat Aug 25, 2018 3:37 pm

Are you using a 5A BEC ?
ErSky9x on Taranis, Sky9x, 9Xtreme, Er9x on 9x with Smartieparts Programmer with TelemetrEZ Board
3D Printing: (http://openrcforums.com/forum/viewforum.php?f=85)

pmullen503
Posts: 232
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

Re: SP-FLVS causing radio interference?

Post by pmullen503 » Sun Aug 26, 2018 12:49 pm

The BEC is rated at 7A and the telemetry logs show 5.83V.

Richard
Posts: 169
Joined: Sat Mar 29, 2014 10:44 pm
Country: United States
Location: Coral Springs, FL

Re: SP-FLVS causing radio interference?

Post by Richard » Sun Aug 26, 2018 1:54 pm

Just for curiosity, check in the telemetry log RSSI vs RX voltage. I guess you have the antennas at 90 degrees from each other. Anyway, I think the "bad guy" is the TX battery.
Richard


User avatar
bob195558
Posts: 1901
Joined: Sun Dec 16, 2012 7:24 pm
Country: United States
Location: New England, Vermont
Contact:

Re: SP-FLVS causing radio interference?

Post by bob195558 » Sun Aug 26, 2018 10:21 pm

I can not remember, but does the Taranis also have a Watch Battery in it (to keep date and time), like the 9XTreme board does ?
ErSky9x on Taranis, Sky9x, 9Xtreme, Er9x on 9x with Smartieparts Programmer with TelemetrEZ Board
3D Printing: (http://openrcforums.com/forum/viewforum.php?f=85)

pmullen503
Posts: 232
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

Re: SP-FLVS causing radio interference?

Post by pmullen503 » Sun Aug 26, 2018 10:49 pm

The telemetry logs show a rock solid rx voltage of 5.83V. The antennas are at 90 degrees and receiver and antenna mounted mid plane about 8" behind the battery and voltage sensor. I removed the sensor and got about a 15db improvement on the next flight.

What about the S-port lead itself? It's flat servo wire.

The RTC battery had in fact died 6 weeks before. You can tell because the log file becomes huge as all those flights get added to the 01/01/2010 file. The battery has been replaced but I have not tried to recreate the low RSSI condition with the sensor.

Richard
Posts: 169
Joined: Sat Mar 29, 2014 10:44 pm
Country: United States
Location: Coral Springs, FL

Re: SP-FLVS causing radio interference?

Post by Richard » Mon Aug 27, 2018 12:36 am

Well, honestly, I cannot give a reasonable answer to how the Sensor can affect the RSSI. Tomorrow, I will make a quick test in the field, by disconnecting the sensor in my plane and then will check RSSI straight in the Telemetry screen. May be that have always happened and I didn't realize, given that I have been using the sensor from day 1.
About the RTC, after 8 years and didn't even know that there was one inside the TX, and therefore I cannot imagine how can that affect the TX power.
On other hand, its a pity that with all the power OpenTX has, there is not a report on emitted signal power.
Richard

pmullen503
Posts: 232
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

Re: SP-FLVS causing radio interference?

Post by pmullen503 » Mon Aug 27, 2018 1:40 am

I appearantly flew for six weeks trouble free with a dead RTC battery.

I'll have to come up with a more controlled scenario for testing and documenting any effect of using the sensor.

User avatar
Kilrah
Posts: 9660
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: SP-FLVS causing radio interference?

Post by Kilrah » Mon Aug 27, 2018 5:39 am

RTC battery has no effect on transmission or operation besides keeping the time.
Richard wrote:
Mon Aug 27, 2018 12:36 am
On other hand, its a pity that with all the power OpenTX has, there is not a report on emitted signal power.
OpenTX can't report on something the hardware doesn't provide...

Richard
Posts: 169
Joined: Sat Mar 29, 2014 10:44 pm
Country: United States
Location: Coral Springs, FL

Re: SP-FLVS causing radio interference?

Post by Richard » Mon Aug 27, 2018 6:54 pm

You have point Kilrah.
By the way, is there any doc showing the warning icons in the top line of the main screen? (Where the SD card icon shows). And what those icons are trying to tell us? I remember seeing a couple of other icons there but I was not able to force them up to take a picture and be more specific.
Thanks a lot.
Richard

User avatar
Kilrah
Posts: 9660
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: SP-FLVS causing radio interference?

Post by Kilrah » Mon Aug 27, 2018 7:01 pm

Believe the only ones are trainer cable connected (either master or slave) and logs recording in progress.

Richard
Posts: 169
Joined: Sat Mar 29, 2014 10:44 pm
Country: United States
Location: Coral Springs, FL

Re: SP-FLVS causing radio interference?

Post by Richard » Mon Aug 27, 2018 7:25 pm

I guess the one looking like a snake should be the USB cable. I can check the log recording in the companion simulator.
Richard

User avatar
Kilrah
Posts: 9660
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: SP-FLVS causing radio interference?

Post by Kilrah » Mon Aug 27, 2018 7:26 pm

The "snake" with a jack at the end is a cable that makes either an M or an S and that's the trainer connection. USB is the obvious USB symbol. Recording is the usual big dot.

Richard
Posts: 169
Joined: Sat Mar 29, 2014 10:44 pm
Country: United States
Location: Coral Springs, FL

Re: SP-FLVS causing radio interference?

Post by Richard » Mon Aug 27, 2018 7:44 pm

Ok. Got it thank you. Will copy your message in my OpenTX "folder".
Richard

Post Reply

Return to “FrSky Taranis radio”