Spektrum debuts Quick Connect to address voltage drop concerns

[Boggy]

That problem I believe was resolved on all spektrum rx after July 2007. I know on my latest rx that doesn't happen as we tested it when I did all the tests on the Align BEC a week or so back.

this is from page 22 of the dx6i manual. paragraph 3 is most relavent

Following are a few common questions from customers:
1. Q: Which do I turn on first, the transmitter or the receiver?
A: It doesn’t matter, if the receiver is turned on first-the throttle channel doesn’t put out a pulse position
at this time, preventing the arming of electronic speed controllers, or in the case of an engine powered
aircraft, the throttle servo remains in its current position. When the transmitter is then turned on
the transmitter scans the 2.4GHz band and acquires two open channels. Then the receiver that was
previously bound to the transmitter scans the band and finds the GUID (Globally Unique Identifier code)
stored during binding. The system then connects and operates normally. If the transmitter is turned
on first, the transmitter scans the 2.4GHz band and acquires two open channels. When the receiver
is turned on, the receiver scans the 2.4GHz band looking for the previously stored GUID, and when it
locates the specific GUID code and confirms uncorrupted repeatable packet information, the system
connects and normal operation takes place. Typically this takes 2 to 6 seconds.
2. Q: Sometimes the system takes longer to connect and sometimes it doesn’t connect at all. Why?
A In order for the system to connect (after the receiver is bound) the receiver must receive a large number
of continuous (one after the other) uninterrupted perfect packets from the transmitter in order to connect.
This process is purposely critical of the environment ensuring that it’s safe to fly when the system does
connect. If the transmitter is too close to the receiver (less that 4 feet) or if the transmitter is located near
metal objects (metal transmitter case, the bed of a truck, the top of a metal work bench, etc.) connection
will take longer and in some cases connection will not occur as the system is receiving reflected 2.4GHz
energy from itself and is interpreting this as unfriendly noise. Moving the system away from metal
objects or moving the transmitter away from the receiver and powering the system up again will cause
a connection to occur. This only happens during the initial connection. Once connected the system
is locked, and should a loss of signal occur (fail-safe), the system connects immediately (4ms) when
signal is regained.
3. Q: I’ve heard that the DSM system is less tolerant of low voltage. Is this correct?
A: All DSM receivers have an operational voltage range of 3.5 to 9 volts. With most systems this is not a
problem as in fact most servos cease to operate at around 3.8 volts. When using multiply high current
draw servos with a single or inadequate battery/ power source, heavy momentary loads can cause the
voltage to dip below this 3.5 volt threshold thus causing the entire system (servos and receiver) to
brown out. When the voltage drops below the low voltage threshold (3.5 volts), the DSM receiver must
reboot (go through the start up process of scanning the band and finding the transmitter) and this can
take several seconds.

��������

: Receivers manufactured after July of 2007 offer a quick connect feature that reconnect

immediately when recovering from a low voltage “brown out.”
Please read the receiver power requirement on page 21 as this explains how to test for and prevent
this occurrence.

[Boggy]

here is page 21 how to prevent it!



20

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The AR6200 features the SmartSafe™ fail-safe system.
SMARTSAFE:
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��������

: Fail-safe positions are stored via the stick and switch positions on the transmitter

during binding.
��������������������������������������
Smartsafe is ideal for most types of electric aircraft and is also recommended for most types of gas- and glowpowered
airplanes and helicopters. Here’s how SmartSafe works.
��������������������������������������
When the receiver only is turned on (no transmitter signal is present), the throttle channel has no output, to avoid
operating or arming the electronic speed control. In glow-powered models, the throttle servo has no input so it
remains in its current position.
��������������������������������
When the transmitter is turned on, and after the receiver connects to the transmitter, normal control of all channels
occurs. After the system makes a connection, if loss of signal occurs, SmartSafe drives the throttle servo only to its
preset fail-safe position (low throttle) that was set during binding. All other channels hold their last position. When
the signal is regained, the system immediately (less than 4 ms) regains control.
�������������������������������������������������� ����������������������������

21

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With all radio installations, it is vital the onboard power system provides adequate power without interruption
to the receiver even when the system is fully loaded (servos at maximum flight loads). This becomes especially
critical with giant-scale models that utilize multiple high torque/ high current servos. Inadequate power systems
that are unable to provide the necessary minimum voltage to the receiver during flight loads have become the
number-one cause of in-flight failures. Some of the power system components that affect the ability to properly
deliver adequate power include: the selected receiver battery pack (number of cells, capacity, cell type, state of
charge), switch harness, battery leads, regulator (if used), power bus (if used).
While Spektrum’s receivers’ minimum operational voltage is 3.5 volts, it is highly recommended the system
be tested per the guidelines below to a minimum acceptable voltage of 4.8 volts during ground testing. This
will provide head room to compensate for battery discharging or if the actual flight loads are greater than the
ground test loads.
�������������������������������������������������� ��������������������
1. When setting up large or complex aircraft with multiple high torque servos, it’s highly recommend that
a current and volt-meter (Hangar 9 HAN172) be used. Plug the volt-meter in an open channel port in
the receiver and, with the system on, load the control surfaces (apply pressure with your hand) while
monitoring the voltage at the receiver. The voltage should remain above 4.8 volts even when all servos
are heavily loaded.
��������

: The optional Flight Log has a built-in volt meter and it can be used to perform this test.

2. With the current meter in line with the receiver battery lead, load the control surfaces (apply pressure
with your hand) while monitoring the current. The maximum continuous recommended current for a
single heavy-duty servo/battery lead is three amps while short-duration current spikes of up to five
amps are acceptable. Consequently, if your system draws more than three amps continuous or five
amps for short durations, a single battery pack with a single switch harness plugged into the receiver for
power will be inadequate. It will be necessary to use multiple packs with multiple switches and multiple
leads plugged into the receiver.
��������

: The Flight log can not measure current draw. Please note that if the flight log is used to

measure voltage, the HAN172 current meter still must be used to measure the draw of the servos.
3. If using a regulator, it’s important the above tests are done for an extended period of 5 minutes. When
current passes through a regulator, heat is generated. This heat causes the regulator to increase
resistance, which in turn causes even more heat to build up (thermal runaway). While a regulator may
provide adequate power for a short duration, it’s important to test its ability over time as the regulator
may not be able to maintain voltage at significant power levels.
4. For really large aircraft or complex models (for example 35% and larger or jets) multiple battery packs
with multiple switch harnesses are necessary or in many cases one of the commercially available power
boxes/ busses is recommended. No matter what power systems you choose, always carry out test #1
above making sure that the receiver is constantly provided with 4.8 volts or more under all conditions.
5. The latest generation of Nickel Metal Hydride batteries incorporate a new chemistry mandated to be
more environmentally friendly. These batteries, when charged with peak detection fast chargers, have
tendencies to false peak (not fully charge) repeatedly. These include all brands of NiMH batteries. If
using NiMH packs be especially cautious when charging making absolutely sure that the battery is fully
charged. It is recommended to use a charger that can display total charge capacity. Note the number of
mAh put into a discharged pack to verify it has been charged to full capacity.

[Hexagon]

: Receivers manufactured after July of 2007 offer a quick connect feature that reconnect

That explains why when I have try to test the re-start time on my AR6200, AR6100 and AR7000. They all re-start in much less than 1 sec it is only if they are with out power for some time that they take a bit longer to re-boot.

I would suggest that a lot of users will have this feature, but just not know it.


Rob

[moyesboy]

It took me a couple of evenings to separate the power to my rx from the align 2in1 power to my servos. cost 7 servo plug housings, (no crimps needed) and a 2row10 way 0.1" pitch header (found lying about at work). I stuck a 4700uf capacitor on the servo power as well to help the sudden start stops.

however the Quark 33A BEC on my trex seems to be working fine, and I do thrash the little thing. but they are analogue servos on the swash.

[jamiem]

i have considered separating all the power leads out of the servos asnd running them straight from the reg output, but im lazy and dont relish making my wiring even more messy, so for now it stays as is.

[pxr5]

maybe they should be selling the current DX7 as "still in testing stage" since theres issues with quick battery drainage, lockouts and even a badly placed strap hook. it. a blind man could have done a better job. you shouldnt have to go buying diodes and mods when you spend so much on a TX

[jamiem]

mine is all as per it came out of the box, and not one problem to date. surely you could say the same about both 35mhz (glitches should have been ironed out with error checking surely?) and the futaba 2.4 modules and tx's (with reseting GUID's), so i think what you are saying is very very naive. What are these supposed issues with quick battery drainage then? my tx battery lasts an age on a single charge, and the rx reg is nowt to do with the rx power requirements (which are miniscule compared to that of the entire system).

[Ashley Davis]

jesus, how many times do we have to repeat that the lockouts are due to low voltage????? ie. NOT SPEKTRUMS FAULT!!!!
I wish people would read the info instead of perpetuating this blame it all on the tx/rx attitude.

[Boggy]

spot on ashley

[Ade_Law]

jesus, how many times do we have to repeat that the lockouts are due to low voltage????? ie. NOT SPEKTRUMS FAULT!!!!
I wish people would read the info instead of perpetuating this blame it all on the tx/rx attitude.

so why these new RX's then?

Ade

[jamiem]

Totally agree with ashley, and thats hopefully what i was trying to get at in my post....

[Goto10]

jesus, how many times do we have to repeat that the lockouts are due to low voltage????? ie. NOT SPEKTRUMS FAULT!!!!

Well - thankfully no more times according to your previous post earlier in this thread

...I'll only state this one more time...

[ChrisB]

There is nothing wrong with the Spektrum system as a whole,the voltage dropping that low is due to supply issues,all Spektrum have done is to try and address this issue in their products for future safeguards which is good news but the idea is to keep a healthy input voltage.If you had a dodgy fusebox at home that was causing power interruptions and say peeing off your 42inch plasma,you wouldnt blame the TV manufacturers would you..

Also battery duration on the DX7 is exceptional from my experience

[moyesboy]

What are the fast battery drain issues?
Never heard of them!

Tx lasts ages


Problems with supply voltage have crashed many a model, both on 35mhz and on 2.4.
I'm interested to read that servos might stop at 3.8v, I imagine that is digiatl servos, anologue ones might keep going on lower volts than that.

In helis we are using high power servos and in CCPM doing 3D they move suddenly together. We do manoevres that put simulateous high loads through the servos. Yet in most cases the power supply system is very much a standard one, one connecter into the rx, one weedy wire and one on off switch and sometimes a 4xAA nicad rather than a subC. Folks flying large planks have often beefed up the power supply with dual batteries and the like.

I think it would be better is all 6+ channel rxs had at least two inputs for power becuase the std rx plugs are only rated for 3A. I'd also like to see a separate rx power input and servo power input on the rx, which could be joined with a jumper for a std installation or separated for a high power installation.

Note that the spectrum rx's are good for 9v - they are clearly thinking to the future when servos that run directly off a 2 cell lipo are available.

I think a bit of background reading about the unique features of the spectrum system is in order before anyone considers jumping ship to Futaba. Personally I think the Spectrum system has a lot of advantages compared to a channel hopping system. Its the spectrum that is the newer and patented technology - don't be confused by the order that they came to market - futaba just had to go with what they had or see spectrum and JR take a bigger market share.

Of course the security of the RF link is not the only thing, the spectrum Tx programming has some features that could be better. Probably the 9 channel under the JR badge will be better. People might have a tx functionality reason to change. with securty of RX power supply, and avoidence of duplicated Tx ids, both systems should be secure enough to fly without ever encountering any Rf link issues.

By all means stay on 35Mhz - more 2.4Ghz makes 35Mhz safer - but if you are flying a trex450 I'll be standing well back.

[ChrisB]

maybe they should be selling the current DX7 as "still in testing stage" since theres issues with quick battery drainage, lockouts and even a badly placed strap hook. it. a blind man could have done a better job. you shouldnt have to go buying diodes and mods when you spend so much on a TX

here and its incorrect

And i read that Spektrum rejected the channel hopping idea early on,patented their system so Futaba are left with the dregs..

Just read this on Spektrums website.....

There are two main broadcast methods that spread spectrum manufacturers can utilize. One format is called Frequency Hopping Spread Spectrum (FHSS). With an FHSS system, the transmitter transmits a narrow band signal and rapidly jumps from one frequency to the next, spending a few milliseconds on each frequency. Originally, Spektrum engineers started their development with FHSS-based systems because they were relatively easy and inexpensive to develop. However, they soon discovered that FHSS had several limitations that would prevent it from being the optimal solution for RC. While more difficult and costly to develop, our engineers began experimenting with Direct Sequence Spread Spectrum (DSSS) and optimized the modulation scheme to overcome critical response and re-link issues. DSSS systems transmit on a single selected frequency but on a very wide band. Only a small portion of that band is used for specially encoded information. In addition, DSSS offers an increase of processing gain for significant improvements in range. With years of development and testing, the DSSS modulation scheme was optimized for RC car and airplane use, and Spektrum´s DSM 2.4GHz Spread Spectrum Technology was born. DSSS provided engineers and hobbyists with the safety, security, and locked-in feeling that is necessary to maintain total and complete control in any vehicle or aircraft.

..............

And here is the link to their site with more info

http://www.spektrumrc.com/DSM/Technology.aspx#whyDsss