WattFlyer RC Electric Flight Forums - Discuss radio control eflight

WattFlyer RC Electric Flight Forums - Discuss radio control eflight (https://www.wattflyer.com/forums/index.php)
-   RC Radios, Transmitters, Receivers, Servos, gyros (https://www.wattflyer.com/forums/forumdisplay.php?f=68)
-   -   HELP! Spektrum DX7 radio failure? (https://www.wattflyer.com/forums/showthread.php?t=22015)

Lieutenant Loughead 07-16-2007 02:15 AM

HELP! Spektrum DX7 radio failure?
 
Hi.

I had two lockout radio failures on my Spektrum DX7 radio this afternoon.

Do you know what caused this?

Spektrum DX7, AR6100, Phoenix 25 ESC.

The first lockout radio failure recovered in 10 seconds.

The second lockout radio failure recovered in 25 seconds. The airlpane almost hit the ground!

Please help! :blah:

gfdengine204 07-16-2007 02:50 AM

What do you mean by "radio lockout failure"? Did your voltage to the RX drop below 3.5v? If so, it was probably a reboot.

If that is the case, you may want to use a separate radio battery or employ a UBEC to make sure your radio voltage stays up where it needs to be.

simibill 07-16-2007 03:38 AM


Originally Posted by Lieutenant Loughead (Post 227450)
Hi.

I had two lockout radio failures on my Spektrum DX7 radio this afternoon.

Do you know what caused this?

Spektrum DX7, AR6100, Phoenix 25 ESC.

The first lockout radio failure recovered in 10 seconds.

The second lockout radio failure recovered in 25 seconds. The airlpane almost hit the ground!

Please help! :blah:

Has your AR6100 had the upgrade?

Lieutenant Loughead 07-16-2007 03:48 AM

I don't know what upgrade you are talking about. Maybe not. How can I tell?

After flight battery voltage was 12.02 volts.

"radio lockout failure" means "no control from transmitter" and "airplane was flying level, with a slight left turn". Maybe it was AR6100 failsafe positions?

I can't tell if there was power to the prop or not. Both times, the airplane descended gently. The second time, I lost visual over the trees and thought it landed on the roof of a building. Then I saw it at the far end of the parking lot, about 100 yards away, and regained control about 10 feet off the ground!

Twmaster 07-16-2007 05:04 AM

It's that AR6100 as your culprit.

If it does not have a tiny sticker that reads V1.2 (or maybe V1.5) on the end of the case it has defective software and needs to be returned to Horizon for test and upgrade.

I lost my Simple Stick to this problem.

simibill 07-16-2007 12:36 PM


Originally Posted by Lieutenant Loughead (Post 227512)
I don't know what upgrade you are talking about. Maybe not. How can I tell?

See the Bulletin here" http://www.horizonhobby.com/Products...ProdID=SPM6100

gfdengine204 07-16-2007 02:12 PM

Good catch; I forgot about that software snafu.

Lieutenant Loughead 07-16-2007 09:01 PM

All five of my AR6100's have a little sticker which says "v1.2" on them.

I have had this same issue on three of my aircraft now -- I lost my GWS P-38 this morning; airplane and 4s 3150 mAh LiPo destroyed.

I called customer service. The GWS P-38 used an external BEC, which was a "red flag" for customer service. At their request, I am shipping the transmitter and all receivers back to them for testing.

Looks like I'm not flying for a while... :(

Gotta be honest here --> I'm really not happy with a 10 second "glitch" on this Spektrum radio, when the software decides to "reboot"... When it glitched, my old 72 MHz radio only glitched for a second or two...

simibill 07-16-2007 10:17 PM

[QUOTE I called customer service. The GWS P-38 used an external BEC, which was a "red flag" for customer service. At their request, I am shipping the transmitter and all receivers back to them for testing.[/QUOTE]

I would not be surprised if they had said no external BEC was a red flag for them. I believe Spektrum receivers are sensitive to low voltage which might occur when running without an external BEC.

gfdengine204 07-16-2007 10:47 PM

This doesn't sound like an issue with the external BEC, it sounds like a low voltage issue. Perhaps a servo was binding and dropped your voltage too low?

Lieutenant Loughead 07-17-2007 03:06 AM

Not on three different aircraft!

gfdengine204 07-17-2007 03:14 AM

Why not? while it may be coincidental, this also is the first time I have ever heard a complain of your kind. Though in your second post, you said you "lost visual over the trees and thought it landed on the roof of a building". If you flew behind a building, you may have lost the link between the TX and RX. 2.4 GHz is LINE-OF-SIGHT and as such, if you have something between you and the plane it can lose signal. (Of course, you should never let your plane leave your sight, because then YOU CAN'T SEE IT. So, maybe that is what caused the problem in at least one instance.

Also, if you flew behind a line of trees, and there was dense foliage, that can block your signal as well.

Lieutenant Loughead 07-17-2007 04:03 PM

1 Attachment(s)
Sigh -- despite what you are suggesting, this was not pilot error. ??

To this point, this radio (Spektrum DX7) has lost radio contact four different times, on three different aircraft. All four times, the aircraft was in plain sight (not behind a building or tree) when radio contact was lost...

It was after radio loss and uncontrolled glide that the aircraft disapeared behind the trees and the building -- all I could do it watch! (See the attached picture, notice how the red line intersects the two trees to the south of the main building.)

The first radio contact loss was at about 50 feet of altitude.

The second radio contact loss was at about 75 feet of altitude.

The third radio contact loss (see attached picture) was at about 100 feet of altitude.

The fourth radio contact loss was at about 100 feet (disaster of a crash -- airplane BOUNCED 5 to 6 feet in the air after ground impact; airplane and battery destroyed).

Again, Spektrum has agreed the transmitter sounds broken, and has asked me to ship it back to them for repair. I shipped it today. I will let you know what happens.

gfdengine204 07-17-2007 06:24 PM

Well, I am sorry for your losses, and look forward to what Spektrum has to say.

The Bandit 07-17-2007 08:26 PM


Originally Posted by Lieutenant Loughead (Post 228265)
Again, Spektrum has agreed the transmitter sounds broken, and has asked me to ship it back to them for repair. I shipped it today. I will let you know what happens.

So, if they find the unit defective, are they going to replace your loss? Most companies have a disclaimer that they will only replace their broken unit. It will be interesting to see how they address this issue. You did perform your radio signal check right?

DIALED/CHUCK 07-17-2007 09:15 PM

Bottom line...Horizon and Hobbico both have millions invested into spread spectrum technology; and both will do whatever it takes to make people happy.

I have witnessed a few 'loss of signal' instances; all of which had their antennas straight and pointing to the gound (I know...I know...we could usually get away with that with 72)....one was low RX pack voltage.

Chris Klick was flying a 180MPH with one at SEFF when he lost link....with the antenna straight out and at the ground....

As soon as he said "I've lost it" and held the antenna skyward, she re-linked. I was standing next to him spotting.

Quique had his Giant scale on Spektrum dump in the weeds....when he got back to the pit, they pulled his RX and found that, mistakenly, a low voltage RX pack was installed.

Personally, I have never had a hiccup on mine and I use 6100's + 7000's....

But yes, it sounds like a TX issue to me; three planes/three different rx's is absurd....If I had a million dollars, I would bet you are right and it is a TX issue. Stinks, nevertheless.....sorry to hear about it brother.

Keep on Horizon, though, they will do you right. Sorry to hear about it man....stay strong.

--C

Lip84 07-17-2007 09:28 PM

This is very curious. I have been doing tons of research on the DX7 as I am looking to purchase the spektrum system in the near future. In all of my searchings I have not seen anything like this. I would have to agree that the Tx is broken somehow. That is the only explanation, even the software reboots shouldnt take 10-25 seconds.

I hope it works out and I am sorry to hear about the loss of your P-38..thats is one expensive loss with the plane, batt, and both engines...ouch :sad:

My Condolences,

Lip84

Lip84 07-17-2007 09:31 PM


Originally Posted by DIALED/CHUCK (Post 228426)
Bottom line...Horizon and Hobbico both have millions invested into spread spectrum technology; and both will do whatever it takes to make people happy.

-Do you know anything about espritmodel? I was looking to get a DX7 from them. The price is the same as Horizon so I might just go with Horizon if they have an excelent reputation for customer service.



Originally Posted by DIALED/CHUCK (Post 228426)
Chris Klick was flying a 180MPH with one at SEFF when he lost link....with the antenna straight out and at the ground....

As soon as he said "I've lost it" and held the antenna skyward, she re-linked. I was standing next to him spotting.
--C

-Is the spektrum similar to the ol 72mhz in that you arent supposed to point the antenna directly at the aircraft for fear of swamping the rx with signal? Why do they recommend pointing the antenna at the ground? Why did the signal reconnect when we pointed the antenna up?

Rabbitcreekok 07-18-2007 12:40 AM


Originally Posted by Lip84 (Post 228434)
-Do you know anything about espritmodel? I was looking to get a DX7 from them. The price is the same as Horizon so I might just go with Horizon if they have an excelent reputation for customer service.

I purchased my DX-7 from Esprit and they gave great service. If your transmitter fails while under warranty, Horizon will service it under warranty, no matter where you purchase the equipment.

I purchased mine from Esprit because they offer different packages than those offered by Horizon. They rearrange the contents to give you more what you want. I did not want a large receiver or servos and that is what I purchased. Good folks.



Originally Posted by Lip84 (Post 228434)
-Is the spektrum similar to the ol 72mhz in that you arent supposed to point the antenna directly at the aircraft for fear of swamping the rx with signal? Why do they recommend pointing the antenna at the ground? Why did the signal reconnect when we pointed the antenna up?

Don't know the answer to that question. This is the first I have heard about a problem with the antenna pointing at the ground. Looking forward to someones response.

gfdengine204 07-18-2007 12:45 AM

The only time I have heard of a problem with antenna orientation is when the antenna is pointed DIRECTLY at the aircraft. The radio waves eminate out from the antenna shaft, so pointing the tip of the antenna at the receiver exposes it to the weakest signal.

I always have my TX antenna angled so it is exposing the side of the antenna shaft to the aircraft, exposing it to the strongest radio wave eminations.

DIALED/CHUCK 07-18-2007 01:19 AM


Originally Posted by Lip84 (Post 228434)
-Do you know anything about espritmodel? I was looking to get a DX7 from them. The price is the same as Horizon so I might just go with Horizon if they have an excelent reputation for customer service.

What Jim said...;-)



-Is the spektrum similar to the ol 72mhz in that you arent supposed to point the antenna directly at the aircraft for fear of swamping the rx with signal? Why do they recommend pointing the antenna at the ground? Why did the signal reconnect when we pointed the antenna up?
Only time I saw issues is when people DID point their ant at the ground with the 90 degree swivel not bent to 90 degrees. (making the ant less efficient). The tip of their antenna was pointing at the grass.

--C

Lieutenant Loughead 07-18-2007 03:27 AM

Okay -- I'm hearing different things here...

1) The radio will fail if the antenna points at the ground. (I'm sure I did not do this.)

2) The radio will fail if the antenna points directly at the aircraft. (It IS posible I did this.)

So -- what's the deal? Maybe both statements are true? I know you're not supposed to point the antenna at your head -- the way I fly, if i bent the antenna 90-degrees, that's exactly what I would be doing...

What's the best way to orient the antenna? ??

simibill 07-18-2007 04:07 AM

[QUOTE

What's the best way to orient the antenna? ??[/QUOTE]

I don't believe it makes much difference. I personally fly with the antenna at a 45 degree angle pointing towards me.

Twmaster 07-18-2007 04:31 AM


Originally Posted by Lieutenant Loughead (Post 228714)
2) The radio will fail if the antenna points directly at the aircraft. (It IS posible I did this.)

This is called the 'cone of silence' picture your antenna mast sticking up vertical. The radio waves come off of it in well, waves which are emanating out away from the mast. If you were able to see the waves and looked down from the top of the antenna the waves would spread out like ripples in water. since they spread out -sideways- when you point the antenna at the plane it sees no signal.

It's best to have your antenna on the TX bent at 45 deg or 90 deg depending on how you typically hold your TX. The idea is to try keep the TX mast vertical.

Rabbitcreekok 07-18-2007 05:28 AM


Originally Posted by Lieutenant Loughead (Post 228714)
Okay -- I'm hearing different things here...

1) The radio will fail if the antenna points at the ground. (I'm sure I did not do this.)

2) The radio will fail if the antenna points directly at the aircraft. (It IS posible I did this.)

So -- what's the deal? Maybe both statements are true? I know you're not supposed to point the antenna at your head -- the way I fly, if i bent the antenna 90-degrees, that's exactly what I would be doing...

What's the best way to orient the antenna? ??

Just to clarify one thing, the radio will not fail due to the antenna pointing any direction. The receiver may not see an adequate signal and go to a failsafe mode. The DX radios failsafe modes are determined when you bind the receiver to the transmitter. Or there is a factory default if you don't rebind the receiver after it is installed in the airplane.

I don't think you are going to get brain damage by pointing the antenna at your head. Makes no difference. Your head is already surrounded by the radio waves coming off the antenna, as well as about a million or a billion or so other radio waves.

Now if you make a hat out of tinfoil, preferable heavy duty Reynolds Wrap, the radio waves will bounce off the hat and be directed to the receiver in your airplane and reception will be improved. Also your status at the flying field will definitely change.;-):tc:

gfdengine204 07-18-2007 05:34 AM


Originally Posted by Rabbitcreekok (Post 228809)
Now if you make a hat out of tinfoil, preferable heavy duty Reynolds Wrap, the radio waves will bounce off the hat and be directed to the receiver in your airplane and reception will be improved. Also your status at the flying field will definitely change.;-):tc:

Now that has got to be the best advice in this thread so far. ;-)

Prof100 07-18-2007 06:08 AM

Having read this thread and its reiteration of the need to point the antenna in a correct orientation leads me to believe the design is inherently flawed because with one and only one transmitter antenna the possibility exists that it will fail to send a signal that the plane can receive. Therefore, the design needs to be revised to provide two antennas oriented 90 degrees from one another. With two antennas it should cover a broad spectrum of transmission that will not be missed by the airplane receiver.

Just my two cents. I sure wouldn't by one of these radios if the antenna position / orientation is that critical. The failure mode effects are extremely expensive!!!

Lieutenant Loughead 07-18-2007 03:21 PM


Originally Posted by Rabbitcreekok (Post 228809)
Now if you make a hat out of tinfoil, preferable heavy duty Reynolds Wrap, the radio waves will bounce off the hat and be directed to the receiver in your airplane and reception will be improved. Also your status at the flying field will definitely change.;-):tc:

LOL -- okay... I'm going to do this, and take a picture, and post it here! :ws:

I looked through my Spektrum DX7 instruction manual, and DID manage to find a statement about not pointing the antenna directly at your aircraft. It's on one of the last few pages of the manual... Again, it IS possible this was my problem... When I regained control of the P-51 (about 100 yards away, 10 feet off the ground, on the other side of the parking lot), I had lost sight of the airplane and thought I crashed it -- I hung my head low, and dropped the transmitter (the lanyard held it to my neck) -- THAT's when I saw the P-51, tried again, and saw that I had control of the aircraft!

Also, I'm wondering something -- does any RF radiate from the BASE of the antenna? What I mean to say is this -- if you bend the antenna 90 degrees, is your Spektrum radio effectively transmitting on two different antennas (90 degrees to eachother)?

Lieutenant Loughead 07-18-2007 03:27 PM

3 Attachment(s)
A few pictures of the carnage...

Here's the information I included with the Spektrum DX7 I shipped back for repair:

Rest In Pieces!!!

Spektrum DX7 radio lockout on July 16, 2007. First flight was at 7:10, with a duration of 15.6 minutes no problems. Second flight (with fresh battery) was at 7:30, with a duration of 2.1 minutes radio lockout for 10 seconds. Airplane nosed over from approximately 100 feet, and hit ground so hard it BOUNCED five to six feet in the air. After flight battery voltage was 16.52 volts. Battery was a CommonSenseRC 4s 3150 mAh LiPo. Speed controls were twin Castle Creations Phoenix 25s. This airplane used a Dimension Engineering SmartBEC.

Lip84 07-18-2007 03:40 PM


Originally Posted by Prof100 (Post 228838)
Having read this thread and its reiteration of the need to point the antenna in a correct orientation leads me to believe the design is inherently flawed because with one and only one transmitter antenna the possibility exists that it will fail to send a signal that the plane can receive. Therefore, the design needs to be revised to provide two antennas oriented 90 degrees from one another. With two antennas it should cover a broad spectrum of transmission that will not be missed by the airplane receiver.

Just my two cents. I sure wouldn't by one of these radios if the antenna position / orientation is that critical. The failure mode effects are extremely expensive!!!

By this logic you shouldnt be flying ANY rc aircraft. The same rules apply to 27, 72, and 2.4 ghz radio waves. So be careful where you point your Tx no matter what the frequency. Just thought I would let you know ;-)

Prof100 07-18-2007 06:54 PM

:red:

Originally Posted by Lip84 (Post 228972)
By this logic you shouldnt be flying ANY rc aircraft. The same rules apply to 27, 72, and 2.4 ghz radio waves. So be careful where you point your Tx no matter what the frequency. Just thought I would let you know

From what I am reading the Spektrum 2.4 ghz is much more sensitive to antenna orientation. If it is not, then I am wrong and better fly control line.:red:

Lip84 07-18-2007 07:20 PM

Haha, yea...control line FTW :Q

Do you have a link to a source on that Prof? I dont doubt you but am curious since I have not seen this and have been doing research on the DX7 system recently.

lip84

Prof100 07-18-2007 07:48 PM


Originally Posted by Lip84 (Post 229078)
Haha, yea...control line FTW :Q

Do you have a link to a source on that Prof? I dont doubt you but am curious since I have not seen this and have been doing research on the DX7 system recently.

lip84

lip84,

I don't have an annotated bibliography of my conclusions since I feel like I am being cross-examined in a product liability case by the defendant, Spektrum radios. Seriously, I just recall in several reviews I have read the authors dwelled on the importance of proper antenna orientation. Even Horizon's (they market them) writeup devotes 5 paragraphs to signal fade and how the "dual link" featue counters any fade (a euphemism for losing contact) problems. See below:

http://www.horizonhobby.com/Articles...ID=1535&Page=2

My thoughts are the addition of the dual link feature is a counter measure for potential or probable signal losses.

gfdengine204 07-18-2007 07:49 PM


Originally Posted by Prof100 (Post 228838)
Having read this thread and its reiteration of the need to point the antenna in a correct orientation leads me to believe the design is inherently flawed because with one and only one transmitter antenna the possibility exists that it will fail to send a signal that the plane can receive. Therefore, the design needs to be revised to provide two antennas oriented 90 degrees from one another. With two antennas it should cover a broad spectrum of transmission that will not be missed by the airplane receiver.

Just my two cents. I sure wouldn't by one of these radios if the antenna position / orientation is that critical. The failure mode effects are extremely expensive!!!

I agree with Lip; your logic is flawed. It's simple; do NOT point the tip of the antenna at your rx. But then, you shouldn't do that with ANY transmitter like these.

Lip84 07-18-2007 08:23 PM

Prof,
I meant no disrespect and did not want to make you feel like you were being cross examined in a court case. You simply made me aware of information that I had not been aware of prior to your input and wanted to see it first hand. that is all. I am sorry if you felt that I was attacking you, that was not my intent at all.

Lip84

gfdengine204 07-18-2007 08:25 PM


Originally Posted by Prof100 (Post 229094)
lip84,

I don't have an annotated bibliography of my conclusions since I feel like I am being cross-examined in a product liability case by the defendant, Spektrum radios. Seriously, I just recall in several reviews I have read the authors dwelled on the importance of proper antenna orientation. Even Horizon's (they market them) writeup devotes 5 paragraphs to signal fade and how the "dual link" featue counters any fade (a euphemism for losing contact) problems. See below:

http://www.horizonhobby.com/Articles...ID=1535&Page=2

My thoughts are the addition of the dual link feature is a counter measure for potential or probable signal losses.

And when I read those statements, I took them to mean the Dual Link feature is not to overcome a TX shortcoming, but the possibility of the rx antenna being shielded by an engine or motor in the aircraft.

Prof100 07-18-2007 08:46 PM


Originally Posted by Lip84 (Post 229120)
Prof,
I meant no disrespect and did not want to make you feel like you were being cross examined in a court case. You simply made me aware of information that I had not been aware of prior to your input and wanted to see it first hand. that is all. I am sorry if you felt that I was attacking you, that was not my intent at all.

Lip84


lip84,

I never felt disrespected nor did I feel I was being attacked. My response was simply a poor attempt at humor.

I would like to have a radio system that doesn't require crystal changes, is bullet proof in terms of interference, and does not fade or lose communication with a plane. The new Spektrum radio systems are extremely appealing because they appear to meet those needs.

However, my experience taught me (albeit scattered over 25 years of RC in both surface and air) was alarmed by the amount of information provided about the veracity of the new Spektrum systems in terms of fade or communication loss. I am always suspicious when I hear a sales pitch that stresses features to counter problems you might have with the product you are considering buying.

Prof100 07-18-2007 08:55 PM


Originally Posted by gfdengine204 (Post 229123)
And when I read those statements, I took them to mean the Dual Link feature is not to overcome a TX shortcoming, but the possibility of the rx antenna being shielded by an engine or motor in the aircraft.

I would think the Dual Link feature is to overcome a shortcoming of the radio system, with system being a key word.

Rabbitcreekok 07-18-2007 09:02 PM


Originally Posted by Prof100 (Post 229159)
lip84,

I never felt disrespected nor did I feel I was being attacked. My response was simply a poor attempt at humor.

I would like to have a radio system that doesn't require crystal changes, is bullet proof in terms of interference, and does not fade or lose communication with a plane. The new Spektrum radio systems are extremely appealing because they appear to meet those needs.

However, my experience taught me (albeit scattered over 25 years of RC in both surface and air) was alarmed by the amount of information provided about the veracity of the new Spektrum systems in terms of fade or communication loss. I am always suspicious when I hear a sales pitch that stresses features to counter problems you might have with the product you are considering buying.


With our our old systems, we has a long antenna trailing behind our models as they flew. Or the antenna was hidden inside the fuselage or wing, but it was long.

The 2.4 Ghz systems use short, 2" or so, antennas, due to the higher frequency. Because these antennas could be blanked out by a large lump of metal in the front, read engine, they use 2 separate links and antennas. This is to assure that they can always receive a signal. Folks are flying 200mph turbine powered jets with the 2.4 Ghz systems.

With anything new there are going to be lots of rumors about the systems, as well as some problems. These problems will be reported with enthusiasm, as they should. The old systems have problems but they aren't reported on forums since it is not news.

I like my DX systems and have had no problems. But then, I did not have problems with the 72 Mhz systems.

Prof100 07-18-2007 09:19 PM


Originally Posted by Rabbitcreekok (Post 229173)
With our our old systems, we has a long antenna trailing behind our models as they flew. Or the antenna was hidden inside the fuselage or wing, but it was long.

The 2.4 Ghz systems use short, 2" or so, antennas, due to the higher frequency. Because these antennas could be blanked out by a large lump of metal in the front, read engine, they use 2 separate links and antennas. This is to assure that they can always receive a signal. Folks are flying 200mph turbine powered jets with the 2.4 Ghz systems.

With anything new there are going to be lots of rumors about the systems, as well as some problems. These problems will be reported with enthusiasm, as they should. The old systems have problems but they aren't reported on forums since it is not news.

I like my DX systems and have had no problems. But then, I did not have problems with the 72 Mhz systems.


Jim,

Great comments, thanks. I, too, have never had any problems with 72 mhz radios.


All times are GMT +1. The time now is 12:19 PM.

Powered by: vBulletin
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.06837 seconds with 7 queries