START HERE |
|
Register | FAQ | PM | Events | Groups | Blogs | Calendar | Mark Forums Read |
Unregistered
|
2.4G Spektrum Radios Spektrum 2.4 Gigahertz Radios and Technology |
|
LinkBack | Thread Tools | Display Modes |
08-23-2019, 07:59 PM | #1 (permalink) |
Registered Users
Join Date: Apr 2007
Location: UK, Kent coast
|
Think I have range issues with the DX7S
This is me thinking out loud here and also welcome suggestions / thoughts. I have a DX7S and a DX8 gen1.
I've flown these two for a number of years with pretty much perfect reliability. But recently a new model which I am flying with the DX7s went into failsafe (Spartan VX1) and the logs show multiple signal losses, sat changes etc. I have now concluded that I highly suspect an issue with the DX7s. This is because I swapped the sats - had the same problem - swapped the entire FBL with cables and sats and although it seemed better it STILL had a failsafe event. I then checked the logs of several other helis I fly with this same TX and although none of them failsafed I see loads of signal loss, antenna change etc. I think some helis are a bit more vulnerable due to the amount of potential obstruction from carbon frames etc. which could account for one heli appearing to suffer more than others being flown with the same TX. Reading in an old thread somewhere it was suggested to try re-seating the RF board and antenna connector. So I have done that just now, not yet tested. What I will try next though, is to take the problem heli and bind it to the DX8 and then see how well it range checks etc. Sooooooo, any thoughts on this are welcome. Is there any other behaviour of the TX that is an indicator of a loose RF board or antenna? Could this kind of thing be intermittent? And lastly - it does make me think maybe it's time to think about moving over to the gen 2 Spektrum. Although, until this latest issue I have been totally happy with my TXs and have had no motivation to change.
__________________
HD Cell 750, RJX Vector, TDR, TDSF, Kasama Dune and Faifa, Minicopter Triabolo 700, Beam Avantgarde, JR E8 leggero, Suzi Laos, Shape 9, Shape S8, Rave 450, TRex 500, Raptor E700, Compass Warp, Steam 700, Spirit, Spartan, Jeti. |
Sponsored Links | |||
Advertisement |
|
08-24-2019, 08:09 AM | #2 (permalink) |
Registered Users
Join Date: Sep 2013
|
There's a range test procedure for the transmitter described in the manual. There's a way to put it in a "low power" mode that limits the range considerably, and then you test to see if you can still control a model from about 30 meters away. If it works, the full range should be OK. If the test fails, there's a problem on one end or the other. You could do that test with a couple of different models without actually flying them to see what happens.
Spektrum support is fantastic here in the U.S., and they'd be willing to check that transmitter for you and fix it if need be. Not sure how they are overseas, though. You'd probably be very happy with a new transmitter. The big plus about them is that you can put any function you like on any switch. On the DX7S every switch has a name - FMode, Hold, etc. - which ends up restricting which features of the transmitter can be assigned to each switch. The new ones simply call the switches A, B, C, etc. and any switch can do anything. Another huge thing is the voice callouts. It sounds like a gimmick, but not only does the TX acknowledge when you flip a switch, but you can also use that function to remind yourself what each switch does. Before powering up a model I haven't flown in a while, I will flip all of the switches to have the TX remind me what they do in each position. While I try to make the switch locations consistent across models, some models have more switches or do slightly different things. Finally, it's great that the model files for the SD card are all compatible across all the Gen2 transmitters. You can make a file with a DX9 and import it in a DX6e. The DX7S has a unique format, and so did the original DX8. Neither one of those SPM formats will read into a Gen2 transmitter. If you're used to the vibration alert, then you'll miss that unless you move all the way up to a DX9. The DX9 is the lowest model that's physically built very similar to your DX7S. The DX6 and DX8 have a different body, and then the DXe/6e/8e are yet another design. Here's an excellent chart that details the differences between all of the current models. If there's a specific thing that's important to you, this chart should help you choose one that still has that feature. http://www.spektrumrc.com/Content/Me...Comparison.pdf |
08-24-2019, 08:11 AM | #3 (permalink) |
Registered Users
Join Date: Sep 2008
Location: Smyrna, GA
|
Are your models RX antenna mounted in such a way that there are blind spots from the carbon frame, electronics or battery pack in any position if you walk completely around the model? If one shadows, then there has to be another still in sight and also all while looking at the model from the bottom.
Also how is the TX antenna positioned when you are flying. Is it out completely straight? If so, then you may want to try again with the tip bent up or sideways at a 45-90* angle as the signal comes off of the antenna in a large donut shaped ring with the weakest part of the signal right at the tip, so you dont want the tip pointing directly at the model The new gen TX models have the small fixed antenna, however they are dual diversity so there is another one running 90* to the one you see on top through the handle to provide a broader coverage spectrum. Activate the range test function on the TX and go out the proper distance from the model and test the controls while walking completely around the model to see if you hit any RX blind spots. I know you said you can see the RX data in the logs, but you can also physically see if there are any dropouts easily even if you are doing this alone by folding the main blades back together at zero pitch as any collective movement will be greatly exaggerated at the tips and easy to see even from a distance.
__________________
Tony Synergy 516, Gaui R-5 Speed (RIP), Cypher Vtol Jet (RIP), Spirit FBL, Hobbywing and Scorpion Tribunus ESC, Xnova motors. The girl in my DX9 tells them all what to do |
08-24-2019, 08:44 AM | #4 (permalink) | |
Registered Users
Thread Starter
Join Date: Apr 2007
Location: UK, Kent coast
|
Yeah, I did mention range testing the DX8 but I guess I didn't emphasis it.
Back when I was using the original DX7 (which I still have actually). I used to do a range check first thing when I got to the field, every time. And I never ever had a model fail the range check. So, slowly, over time, I got lazy and stopped doing range checks regularly :-( When I built a gasser a few years ago, I got very scientific about sat placement due to the large potential blindspot that could occur with the engine, pipe and carbon frames. So after that I kept the same formula for sat placement on all my helis (avoiding blockage from carbon frames, keeping one at line of sight from any angle, having the two sats on different vertical / horizontal planes etc.). But historically all the Spektrum stuff I have used for the last ten years has been incredibly robust and in general not all that picky about the exact placement of sats. I am well aware of the general best practices regarding sat placement, TX antenna etc. BTW - there was a conversion app that someone made, to transfer SD card data between the 1st gen DX7S and DX8 and the newer DX's. It has been 5 or 6 years ago but I transferred some model settings for a friend and it worked. I'll see if I can find it again. ---- found it: https://spmtool.azurewebsites.net/ But as I'm using the same FBL unit on most of my helis there is actually very little heli-specific settings (just throttle %), so it's really not even an issue moving a model to a new TX. Quote:
__________________
HD Cell 750, RJX Vector, TDR, TDSF, Kasama Dune and Faifa, Minicopter Triabolo 700, Beam Avantgarde, JR E8 leggero, Suzi Laos, Shape 9, Shape S8, Rave 450, TRex 500, Raptor E700, Compass Warp, Steam 700, Spirit, Spartan, Jeti. Last edited by trillian; 08-24-2019 at 10:09 AM.. |
|
08-24-2019, 11:07 AM | #5 (permalink) |
Registered Users
Thread Starter
Join Date: Apr 2007
Location: UK, Kent coast
|
Yep, my 7S has a fault
Quick update: I took out the heli I've had the most recent problems with, took it into the carpark and set it in a fixed position and walked 30 paces. It would not range check properly with the DX7S, movements very jerky if at all. I tried several times with similar results.
So bound it to the DX8 and took it out to the same place in the carpark and walked to the same place as before and it range checks perfectly, movements are instant and smooth. In the past, Spektrum support was incredibly good here as well, but I haven't needed anything from them in a long time so I hope that is still the case. I'll contact them and ask if they can service this TX and what it might cost. I recall someone saying the service centre was moved, but maybe that's my imagination, we shall see.
__________________
HD Cell 750, RJX Vector, TDR, TDSF, Kasama Dune and Faifa, Minicopter Triabolo 700, Beam Avantgarde, JR E8 leggero, Suzi Laos, Shape 9, Shape S8, Rave 450, TRex 500, Raptor E700, Compass Warp, Steam 700, Spirit, Spartan, Jeti. |
09-07-2019, 10:33 PM | #6 (permalink) |
Registered Users
Join Date: Sep 2011
Location: Dallas
|
Inspect and Repair Antenna Connectors
Inspect the 7s before shipping Tx for inspection/repair.
Open the Tx Find the small antenna connector attached to the RF module. R&R the connector to insure a good connection. Look for any debris or corrosion clean with IPA On thing to look for is the small pin to see if anything is bent. If you find a bend or any damage to the connector I would replace the antenna. Also While your in there you may want to just replace the antenna. Not that it will fix the problem but $12 is cheep test than shipping the Tx in for inspection / repair.
__________________
Align450L / 470/150 DFC/Blade stuff DJI/AR Drone |
09-09-2019, 05:55 AM | #7 (permalink) |
Registered Users
Thread Starter
Join Date: Apr 2007
Location: UK, Kent coast
|
I did have a look inside before I did my range check comparison. I checked that the RF board was seated properly and the antenna was connected as it should be and it appeared to be OK.
I described the problem to the UK service centre and they said it sounds like it might need a new RF board which would be £49.95. So at the moment I haven't done anything with it. I moved all my helis to the DX8. I kinda think at 55 ish quid (adding in the postage to them), it's really a large paperweight. I have to think about it. I might revive my old DX7 as an emergency backup TX, it just needs a new plastic antenna end section and it always worked perfectly.
__________________
HD Cell 750, RJX Vector, TDR, TDSF, Kasama Dune and Faifa, Minicopter Triabolo 700, Beam Avantgarde, JR E8 leggero, Suzi Laos, Shape 9, Shape S8, Rave 450, TRex 500, Raptor E700, Compass Warp, Steam 700, Spirit, Spartan, Jeti. Last edited by trillian; 09-09-2019 at 05:55 PM.. |
09-11-2019, 06:01 AM | #8 (permalink) |
Registered Users
Join Date: Mar 2015
Location: Germany / Nuremberg
|
Hi,
I had a silver DX8G1 for a while. The plastic antenna easily can get corrupted in the middle where you fold it 90 degree to its side. If an antenna replacement (and internal checking if the HF plug directly sits on top of the board or got loose) does not fix your problem permanently, you might want to check the telemetry flightlog with an all-in telemetry (T) receiver or external TM1000 module: - Are antenna fades A / B at the 0xFF (=255) maximum on older receivers? What are your numbers on newer (e.g T) receivers? - Do you usually get higher (more than >40) FrameLosses (e.g 40-90) more than once? - Do you have a bad signal quality even with reduced range power 30-35m (manual says 30 feet): My AR6210+TM1000 got to ~62m without any Holds before the FrameLosses increased dramatically! A hold will only occur if the FrameLosses are several in a row (consecutive order). But HH support suggested to me (with constant >40F, different planes, whole season) speaking to several people to send the Dx8G1 in and they replaced the HF module for free (end of 2012). You may want to try another (good) ESC. Some (two) ESCs with SBECs did not behave too well in my test ground setup either; one ESC was from a vendor of EPP planes where I got my ARF glider from so I did not really expect that...the other one was a cheaper V1 version (now superseeded by V2 / V2.1). What I also could see: If the lipo power cable or receiver (might affect all electronics like servos, motor, etc.) are in the near (or on top of) the Spektrum receiver antennas (e.g AR6210) I could clearly see that the FlightLog Fades got affected. One of many reasons why I finally got the satellite extender cable and mounted the Spektrum satellite vertical (for 360 degree possible receiving) on the back of the horizontal stabilizer (end of the fuselage before the rudder). I had more success when I was switching to a better L-BEC ESC (even when the DX8G1 HF module was not yet exchanged), even with the PZ P51D or PZ F4F warbirds in nearer distance flight. With the receiver in the middle of the fuselage the P51D was better on the Fades whereas the F4F required that you put everything (lipo, motor, ESC, receiver servos) in the front which affected my tested numbers. My FrameLoss / noise problems clearly did not only have something to do with flying higher / more far away from me.
__________________
Walkera Devo 10/DeviationTX (12CH DSMx & telemetry)...Ex-DX8...Blade 4503D...Walkera V120D02s...XK K110...Blade 200QX quad...Ex-NanoCPX...Ex-120SR...StrykerQ (LEDs, M2 tuning)...Ex-MPX EGP...PPZ P51-D...PZ Wildcat (searching fuselage-firewall) |
09-11-2019, 09:35 AM | #9 (permalink) | |
Registered Users
Thread Starter
Join Date: Apr 2007
Location: UK, Kent coast
|
Thanks. This is a DX7S, it has no facility to log this kind of signal data. All the FBL unit logs is loss of signal.
It has nothing to do with the ESCs, is not an RX power issue, my range tests prove that. I did think about the potential for fatigue in the antenna at the bend. I think this is unlikely but I will ask the service centre about the probability of it. In any case, I think at this point any repairs, even just the antenna, would need to be carried out and verified by a Spektrum service centre in order to remain covered by my liability insurance. Quote:
__________________
HD Cell 750, RJX Vector, TDR, TDSF, Kasama Dune and Faifa, Minicopter Triabolo 700, Beam Avantgarde, JR E8 leggero, Suzi Laos, Shape 9, Shape S8, Rave 450, TRex 500, Raptor E700, Compass Warp, Steam 700, Spirit, Spartan, Jeti. |
|
09-11-2019, 10:07 AM | #10 (permalink) |
Registered Users
Join Date: Aug 2019
Location: Germany, Bavaria
|
I fully agree. I would refuse to the DX7S, and just keep the DX8.
You might use the DX7 for Sim... |
09-12-2019, 03:36 PM | #11 (permalink) | |
Registered Users
Join Date: Mar 2015
Location: Germany / Nuremberg
|
Quote:
When you do a real flight, you can scroll to the telemetry / flightlog menu. After you plug the flightpack in, you first have to reset the values (e.g max/min receiver voltage). And after you have landed your heli, BEFORE you unplug the lipo flightpack, you can scroll to the telemetry FlightLog menu and take a look on those A/B/L/R + FrameLosses numbers. Of course this only makes sense if you do not expect any problems. Obviously this will not work if your FBL only uses Spektrum satellites connected to it. Check. Theoretically, receiver could have meant BEC (if there are several FlightLog holds). But I meant the power output of the internal HF modul in the DX7s. If the power is not full ~18dbm + antenna gain (~20dbm = 100mw for Europa, 200mw for US) than you might notice a decrease in range. Yes, with the ground range test (reduced transmit power) you can display those telemetry Flightlog Fades A/B/L/R + F + H values as I showed in my previous comment. But you need a T receiver (all-in telemetry) or a TM1000. If your plane or heli uses only Spektrum satellites or a Non-T receiver without any TM1000/TM1100 (for 300/450 size parkflyer helis) the DX7s can't show those FlightLog values directly on the transmitter display while you are doing the (ground) range test. A ground range test with reduced output power (trainer button pressed) - without telemetry - can't show any FlightLog menu!
__________________
Walkera Devo 10/DeviationTX (12CH DSMx & telemetry)...Ex-DX8...Blade 4503D...Walkera V120D02s...XK K110...Blade 200QX quad...Ex-NanoCPX...Ex-120SR...StrykerQ (LEDs, M2 tuning)...Ex-MPX EGP...PPZ P51-D...PZ Wildcat (searching fuselage-firewall) |
|
Thread Tools | |
Display Modes | |
|
|