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May 24, 2018, 18:39:52 PM

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Author Topic: Lost Faith In Spektrum  (Read 2619 times)

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Offline Phil_G

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Re: Lost Faith In Spektrum
« Reply #40 on: May 15, 2018, 01:02:07 AM »
Pah! My 27mhz on blue is untouchable.
Blue was the worst as there were three, and no-one seemed to know which one they were on!
There was 27.225 which was 'blue' in imported american radios, and 27.245 and 27.255 were
both regarded as 'blue'.  When splits arrived this caused mayhem at the top of the band!


« Last Edit: May 15, 2018, 01:06:37 AM by Phil_G »


Offline itsme

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Re: Lost Faith In Spektrum
« Reply #41 on: May 15, 2018, 07:58:20 AM »
Blue was the worst as there were three, and no-one seemed to know which one they were on!
There was 27.225 which was 'blue' in imported american radios, and 27.245 and 27.255 were
both regarded as 'blue'.  When splits arrived this caused mayhem at the top of the band!
I was on blue with my Acoms set. Acoms was definitely the Spekky of the time...and I never had a glitch with that radio,.

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Re: Lost Faith In Spektrum
« Reply #42 on: May 15, 2018, 08:13:25 AM »
Blue was the worst as there were three, and no-one seemed to know which one they were on!
There was 27.225 which was 'blue' in imported american radios, and 27.245 and 27.255 were
both regarded as 'blue'.  When splits arrived this caused mayhem at the top of the band!

Not to mention the practice of reversing Rx/Tx Xtals to get "white"...

PDR
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Offline Phil_G

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Re: Lost Faith In Spektrum
« Reply #43 on: May 15, 2018, 16:48:59 PM »
Not to mention the practice of reversing Rx/Tx Xtals to get "white"...
Its reassuring to see that your memory's as bad as mine Pete  ;D , white was 27.275 and only just within the upper band limit!
Swapping crystals was quite common practise but a bit naughty, any legit receiver crystal in a tx would put it outside the band  :''
One of my Dads homebrew S/C trannies from Practical Wireless didnt have a crystal at all, but instead two beehive trimmers - that one spent most of its time somewhere outside the band so we could fly two superregens at once  :af  Happy daze.

So... Spektrum eh?
Yeah.

Cheers
Phil
« Last Edit: May 15, 2018, 16:52:38 PM by Phil_G »

Offline Bad Raven

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Re: Lost Faith In Spektrum
« Reply #44 on: May 16, 2018, 08:19:42 AM »
In recent years the problem of colour coding 27MHz has got worse as SOME of the Chinese manufacturers have invented their own colour to frequency sequence.

I still use 27MHz extensively for cars with the school club, as I do 40MHz, too. ACOMS and Futaba, both very robust.

Its amusing that the affordable 2.4GHz CAR stuff is coming and going through failures, yet the old 27 and 40 sets carry on and on. Failures on these are usually due to kids dropping them and affecting the crystals, or the inevitable mangled aerials in handling.

The "Code Sport/Etronix" 2.4 car sets were great for turn on and use convenience, but fragile to dropping, prone to suddenly refuse to bind, and now sale is withdrawn. (I assume they got caught on non-LBT format). For a while I used Planet sets and added discs to limit sticks to 2Ch.

You might be amused by the fact that with over 40 2.4Ghz around in a session  I had to colour code the 2.4GHz Tx to each car by two colour taping the handles per make and under labelling the cars !   ::)
The user formerly know as Bravedan........... Well if Prince can do it....................


Offline Phil_G

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Re: Lost Faith In Spektrum
« Reply #45 on: May 19, 2018, 17:47:30 PM »
This is a cracker - read the 8th post down, from 'Percy Verance'   ;D  ;D  ;D
http://www.modelflying.co.uk/forums/postings.asp?th=135840&p=1

Edit: Here's the quote in case it disappears in a PC cleanup:
Quote from: Percy Verance
I'd also recommend Glenn ensures he places his radio gear in the most suitable position. In this particular instance I'd suggest the box it came in.



 

 



« Last Edit: May 19, 2018, 22:16:31 PM by Phil_G »

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Re: Lost Faith In Spektrum
« Reply #46 on: May 19, 2018, 18:25:02 PM »
This is a cracker - read the 8th post down, from 'Percy Verance'   ;D  ;D  ;D
http://www.modelflying.co.uk/forums/postings.asp?th=135840&p=1


Absolutely love it! I'm nicking that one!

PDR

« Last Edit: May 20, 2018, 08:20:03 AM by PDR »
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Offline paulinfrance

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Re: Lost Faith In Spektrum
« Reply #47 on: May 20, 2018, 06:08:01 AM »
Well one of our last Spectrum lovers had another lock out yesterday flying his electric heli, it locked out
when hovering at 10 meters, it went sideways, then nose dived into the ground, he was 10 seconds from throwing the radio to the ground and 'recycling' it with his boots,,,
Mode 2 THE only way to fly

Offline Brian Cooper

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Re: Lost Faith In Spektrum
« Reply #48 on: May 20, 2018, 08:12:51 AM »
Well one of our last Spectrum lovers had another lock out yesterday flying his electric heli, it locked out
when hovering at 10 meters, it went sideways, then nose dived into the ground, he was 10 seconds from throwing the radio to the ground and 'recycling' it with his boots,,,

Well, don't get too smug.  I have seen two cases of radio failure with MULTIPLEX radio in the last couple of weeks. Different sets, different people and different locations.
One locked out and smashed into the ground.  The other one flew away and was last seen heading towards Norway. 
I have every confidence there are many other cases of failures of this brand, but the owners would never dare to make it common knowledge for fear of a knock on the door at midnight followed by being arrested by Multiplex disciples and subsequently publicly burnt at the stake in the morning.  ;)

B.C.
« Last Edit: May 20, 2018, 09:28:28 AM by Brian Cooper »


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Re: Lost Faith In Spektrum
« Reply #49 on: May 20, 2018, 08:31:27 AM »
  I have seen two cases of radio failure with MULTIPLEX radio in the last couple of weeks.
One locked out and smashed into the ground.  The other one flew away and was last seen heading towards Norway. 

You have thought he'd have learnt after the first time...............   :nananana:

Bring back Frightlink Flightlink, all is forgiven.......................maybe.................
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Offline itsme

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Re: Lost Faith In Spektrum
« Reply #50 on: May 20, 2018, 08:51:40 AM »
Well one of our last Spectrum lovers had another lock out yesterday flying his electric heli, it locked out
when hovering at 10 meters, it went sideways, then nose dived into the ground, he was 10 seconds from throwing the radio to the ground and 'recycling' it with his boots,,,
So, I keep beating on about this, but did it failsafe the motor? Its easy to blame the radio, but there may be another cause.

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Re: Lost Faith In Spektrum
« Reply #51 on: May 20, 2018, 09:51:48 AM »
...for fear of a knock on the door at midnight followed by being arrested by Multiplex disciples and subsequently publicly burnt at the stake in the morning.  ;)

The thing is Brian - almost all of the contributions to this thread have been unemotive, objective and evidence-based reportage. The only ones with seemingly religious conviction on the righteousness of their own brand and the apostatic nature of all others are those relating to the Specky stuff. So if indeed there is a radio-brand KGB who knock on doors in the wee hours and drag people off to the gulag for their heretical choices it would seem far more likely that these thugs would have Specky collar studs than any other brand.

It's worth remembering that in the popular literary meme where pitchfork-wielding village folk burn people at the stake the point being made is that the village folk are invariably (a) pig-ignorant and thick as pig-excrement, (b) factually incorrect and (c) usually cynically misled by someone with an axe to grind.

As I said previously - you only need faith where there is doubt, and that's why I don't have any faith in my current or former radio gear.

PDR
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Offline paulinfrance

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Re: Lost Faith In Spektrum
« Reply #52 on: May 20, 2018, 12:55:27 PM »
Well, don't get too smug.  I have seen two cases of radio failure with MULTIPLEX radio in the last couple of weeks. Different sets, different people and different locations.
One locked out and smashed into the ground.  The other one flew away and was last seen heading towards Norway. 
I have every confidence there are many other cases of failures of this brand, but the owners would never dare to make it common knowledge for fear of a knock on the door at midnight followed by being arrested by Multiplex disciples and subsequently publicly burnt at the stake in the morning.  ;)

B.C.

 Smug ? :-\ why ?, it cost my friend a helicopter, and I don't fly Multiplex, and he said after that he shut down the Throttle
 but nothing happened and hitting the deck the battery went it's own way,,  :''
Mode 2 THE only way to fly

Offline Brian Cooper

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Re: Lost Faith In Spektrum
« Reply #53 on: May 20, 2018, 14:34:40 PM »

As I said previously - you only need faith where there is doubt, and that's why I don't have any faith in my current or former radio gear.

PDR

Sounds like both of us have no doubts about our radios,  then.    :af :af
Splendid.

B.C.

Offline Phil_G

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Re: Lost Faith In Spektrum
« Reply #54 on: May 20, 2018, 16:31:54 PM »
I'm not a massive fan though I do frequently use some Spekky stuff in projects (amongst many other brands).
FWIW heres my perspective and the reasons behind it as an electronics & RF engineer primarily interested in the equipment itself.  I dont really do faith, doubt or any particular belief system. I do thoroughly bench test stuff and what I found years ago (dsm2 era) formed an opinion of Spektrum that (perhaps unfairly) has stuck.

Firstly, under test conditions the 3v3 regulator in a typical Spekky receiver showed a substantially high dropout compared to the competition. From this and a widespread misunderstanding of power systems spawned the whole ridiculous 5-cell thing. If a power supply is sagging under load, then a lower ESR supply is the correct approach, not raising the voltage it sags from.

Secondly DSM2 was not strictly a legal protocol, it sidestepped the regulations of the time by claiming that its two parallel frequencies constituted frequency 'hopping', which they clearly dont.   

Third, the two frequencies were chosen at the moment of switch-on, based on what the transmitter, not the receiver, could hear. At ground level, this meant that a potentially problematic distant transmission would not be heard, and a poor choice of frequencies made, which remained fixed throughout the flight - no real-time adaption to conditions.

Fourth, the gap between two chosen frequencies might be widely spaced, which was good - but often adjacent, so one video transmission could trample both.

A couple of more subjective observations -  the number of RF boards replaced by HH.   This simply doesnt happen elsewhere, and, whilst this isnt a problem as such, the reliance on satellite receivers, which makes for an untidy installation which most other manufacturers have managed to avoid.  In theory the extra physical separation is good, but it raises the complexity and volume of the processors workload, where others achieve diversity by simply switching antennas - a physically low-overhead, fast, cheap and perfectly effective method, making Spektrums choice of diversity by having many completely separate receivers look clumsy.
Then the non-standard PPM implementation used by their modules means that to encoder makers, pulse-widths either have to be made adjustable or a Spekky-specific version made. Its just awkward for no reason.

I dont foist these views on anybody, its just what I've found. Things have improved, for example DSMX is one of the (if not the) best implementations yet, combining DSM with FH.  I've a genuine interest in systems but when this 'market leader' was compared with Frsky, a very cheap module-based setup from China, the choice was easy to make.  As I said I do use Spekky, Flysky, Frsky, FASST, Hitec, Corona, even Assan & Flydream in various projects - but, based on functionality, reliability and flexibility, Spekky doesnt do it for me.
 
/2p
Cheers
Phil
« Last Edit: May 20, 2018, 16:33:40 PM by Phil_G »

Offline Steve J

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Re: Lost Faith In Spektrum
« Reply #55 on: May 20, 2018, 17:13:27 PM »
Secondly DSM2 was not strictly a legal protocol, it sidestepped the regulations of the time by claiming that its two parallel frequencies constituted frequency 'hopping', which they clearly don't.   

DSM2 was EN 300 328 1.7.1 compliant. It is not EN 300 328 1.8.1 compliant.

Fourth, the gap between two chosen frequencies might be widely spaced, which was good - but often adjacent, so one video transmission could trample both.

Whenever I have used a scanner when DSM2 transmitters have been in use, the two chosen frequencies have been 40 MHz apart.

I still use DSM2. Three of my biggest models are on DSM2 using the excellent AR9100 receiver and will be for the foreseeable future.

Steve

Offline Steve J

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Re: Lost Faith In Spektrum
« Reply #56 on: May 20, 2018, 17:18:52 PM »
You only need faith where there is the possibility of doubt. The more faith, the greater the doubt. I know pwople wjho have a LOT of faith in Specky stuff...

I suspect that the OP was using faith to mean "complete trust or confidence in someone or something" rather than "strong belief in the doctrines of a religion, based on spiritual conviction rather than proof". I also suspect that you knew this, but felt like making a clever comment for the gallery.

Steve


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Re: Lost Faith In Spektrum
« Reply #57 on: May 20, 2018, 17:25:13 PM »
Fourth, the gap between two chosen frequencies might be widely spaced, which was good - but often adjacent, so one video transmission could trample both.

That's interesting. When we set the analyser to view the band as 80 spot "channels" we foun d that the DSM2 dozen or so transmitters present that evening all always selected a pair of frequencies that were 40 channels apart.

PDR
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Re: Lost Faith In Spektrum
« Reply #58 on: May 20, 2018, 17:27:34 PM »
I also suspect that you knew this, but felt like making a clever comment for the gallery.

Would I do a thing like that? Surely not!

PDR

PS - FWIW I believe you may be confusing the word "faith" with the word "confidence".
« Last Edit: May 20, 2018, 18:11:53 PM by PDR »
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Offline itsme

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Re: Lost Faith In Spektrum
« Reply #59 on: May 20, 2018, 17:48:01 PM »
As for trusting radios, I am guilty of that. I was flying the converted slope soarer I showed on here at our site and took it to a tiny dot in the sky, as it has waaay too much power (we have a notam on the airfield as we share with a skydive school, before anyone shouts about 400'...) then looked down at my Tx - a humble Aurora- and the short stubby aerial, and the tiny dot above me still under perfect control, and you realise just how good stuff is these days.

Sent from my SM-A300FU using Tapatalk


Offline Phil_G

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Re: Lost Faith In Spektrum
« Reply #60 on: May 20, 2018, 18:29:56 PM »
DSM2 was EN 300 328 1.7.1 compliant. It is not EN 300 328 1.8.1 compliant.
What I'm saying Steve is that it was granted a 'pass' on the basis that Spektrum described their two-channel approach as an FHSS system, which strictly it wasnt. But I think you're aware of that  ;)
As DSSS it would under 1.7.1 have been limited to 10mw/mhz had the rules been applied literally.
Its not quite right to say that DSM2 is no longer legal or that its non 1.8.1 compliant. It depends on the erp, at 10mw/mhz it would be perfectly legal today.
Cheers
Phil
« Last Edit: May 20, 2018, 18:35:44 PM by Phil_G »

Offline Steve J

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Re: Lost Faith In Spektrum
« Reply #61 on: May 20, 2018, 18:49:13 PM »
What I'm saying Steve is that it was granted a 'pass' on the basis that Spektrum described their two-channel approach as an FHSS system, which strictly it wasnt.

DSM2 exploited the fact that 1.7.1 wasn't particularly well written. DSM2 is a hybrid FHSS/DSSS in that it hops between two channels. DSMX hops between 23 (?) channels.

In theory the extra physical separation is good, but it raises the complexity and volume of the processors workload, where others achieve diversity by simply switching antennas - a physically low-overhead, fast, cheap and perfectly effective method, making Spektrums choice of diversity by having many completely separate receivers look clumsy.

There are Spektrum receivers that have dual antenna diversity in a single case, e.g. the AR600 and AR6255. There has been at least one Spektrum receiver that has two circuits in a single case, the AR6260. The AR6600T has antenna diversity in the main unit and a remote.

Steve

Offline Phil_G

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Re: Lost Faith In Spektrum
« Reply #62 on: May 20, 2018, 20:29:00 PM »
DSM2 is a hybrid FHSS/DSSS in that it hops between two channels. DSMX hops between 23 (?) channels.
I'm familiar with the protocols Steve and 1.7.1 specified a minimum of 15 hopping channels for FHSS.
As you're well aware DSM2 simply selects two channels which remain fixed and it alternates packets between them.
Its far-fetched in the extreme to compare this to a true FHSS system, but it is how DSM2 was argued through the regs.
Hence my observation in the previous post, above 10mW/M DSM2, whilst actually approved, never truly conformed to the regulatory requirements.
Cheers
Phil
« Last Edit: May 20, 2018, 20:40:22 PM by Phil_G »

Offline Bad Raven

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Re: Lost Faith In Spektrum
« Reply #63 on: May 20, 2018, 20:46:47 PM »
There are Spektrum receivers that have dual antenna diversity in a single case, e.g. the AR600 and AR6255. There has been at least one Spektrum receiver that has two circuits in a single case, the AR6260. The AR6600T has antenna diversity in the main unit and a remote.

And the average modeller likely to buy Spektrum would know and understand all the implications of those and other variants? Spektrum are not alone here, but the confusing coding and sheer number of constantly changing variants is IMO very counterproductive to ensure an overall safe, reliable, easy to understand and use global system.

Are people presented with clear, concise information to be able to correctly choose the right combination to purchase and correctly set up these systems?

The user formerly know as Bravedan........... Well if Prince can do it....................

Offline Steve J

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Re: Lost Faith In Spektrum
« Reply #64 on: May 21, 2018, 07:28:01 AM »
And the average modeller likely to buy Spektrum would know and understand all the implications of those and other variants?

IMHO, the quality of install is much more important than whether the radio gear is Spektrum, Futaba, FrSky etc, so yes, I think that the average modeller should take the time to develop a basic understanding of the RF equipment that they are using and how to install it.

Steve

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Re: Lost Faith In Spektrum
« Reply #65 on: May 21, 2018, 08:13:39 AM »
In the bad old days of 35, it was pretty simple. A new model flyer had a choice of mostly Futaba or JR. Instructions were pretty much the same for all, aerial out of the fuselage etc and do a range check and go flying. Nowadays a degree in computer science is advantageous and there is a bewildering choice of radio gear. Most of which works fine, provided it is installed correctly, thats if you can understand the Chinglese manual. A new flyer does not want to know about protocols and DS whatever. Sometimes I long for the days back of my Challenger 5 when the world was a simpler place! I am now going to go and read the manual for my Aurora in order to understand why my throttle cut is not working....

Offline paulinfrance

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Re: Lost Faith In Spektrum
« Reply #66 on: May 21, 2018, 08:39:44 AM »
In the bad old days of 35, it was pretty simple. A new model flyer had a choice of mostly Futaba or JR. Instructions were pretty much the same for all, aerial out of the fuselage etc and do a range check and go flying. Nowadays a degree in computer science is advantageous and there is a bewildering choice of radio gear. Most of which works fine, provided it is installed correctly, thats if you can understand the Chinglese manual. A new flyer does not want to know about protocols and DS whatever. Sometimes I long for the days back of my Challenger 5 when the world was a simpler place! I am now going to go and read the manual for my Aurora in order to understand why my throttle cut is not working....

 Yes it was simple then, if it crashed it was the radio, :'' if you piled it in on landing it was a radio glitch, $%& the rest was battery failure,  :study:


I gave up petrol completely with all the glitches in my helicopters on FM radios  :-\

But with 2.4 it all works 'except' turbines, crashes are now blamed on 'static eletrickery'  :D
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Offline itsme

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Re: Lost Faith In Spektrum
« Reply #67 on: May 21, 2018, 10:09:39 AM »
Yes it was simple then, if it crashed it was the radio, :'' if you piled it in on landing it was a radio glitch, $%& the rest was battery failure,  :study:


I gave up petrol completely with all the glitches in my helicopters on FM radios  :-\

But with 2.4 it all works 'except' turbines, crashes are now blamed on 'static eletrickery'  :D
Never had problems on PCM. As you say, these days it's not "interference!" It's "brown out! "

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Re: Lost Faith In Spektrum
« Reply #68 on: May 21, 2018, 12:34:28 PM »
As you say, these days it's not "interference!" It's "brown out! "
Only one system I've tested had the significantly higher dropout voltage though Bob.  They may have improved since then but its too late, the completely unnecessary 5-cell 'solution' is now well established  ;D
With a properly specced (sic) power supply, brownouts shouldnt ever happen in R/C systems  :af
« Last Edit: May 21, 2018, 14:56:27 PM by Phil_G »

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Re: Lost Faith In Spektrum
« Reply #69 on: May 21, 2018, 12:38:01 PM »
I've always been amused at the "official" solution to this - putting an additional external electrolytic capacitor across the rails. Whoever believed in that one has clearly never done any sums on the stored charge and the currents involved...

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Re: Lost Faith In Spektrum
« Reply #70 on: May 21, 2018, 18:30:15 PM »
Only one system I've tested had the significantly higher dropout voltage though Bob.  They may have improved since then but its too late, the completely unnecessary 5-cell 'solution' is now well established  ;D
With a properly specced (sic) power supply, brownouts shouldnt ever happen in R/C systems  :af
Still feel safer.....lol

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Re: Lost Faith In Spektrum
« Reply #71 on: May 21, 2018, 18:58:20 PM »
I've always been amused at the "official" solution to this - putting an additional external electrolytic capacitor across the rails. Whoever believed in that one has clearly never done any sums on the stored charge and the currents involved...

PDR
I did see someone recommending using supercapacitors for this on another forum. He did the calculations and used 3 in series to get a suitable voltage and needed around 5F capacitors to store enough charge to cover a low voltage. His system did need an initial connection through a resistor to reduce the charging current to a safe value similar to that used in high voltage ESCs.

Jim
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Re: Lost Faith In Spektrum
« Reply #72 on: May 21, 2018, 23:16:28 PM »
Well, don't get too smug.  I have seen two cases of radio failure with MULTIPLEX radio in the last couple of weeks. Different sets, different people and different locations.
One locked out and smashed into the ground.  The other one flew away and was last seen heading towards Norway. 
I have every confidence there are many other cases of failures of this brand, but the owners would never dare to make it common knowledge for fear of a knock on the door at midnight followed by being arrested by Multiplex disciples and subsequently publicly burnt at the stake in the morning.  ;)

B.C.
Was the pilot wearing the correct sandals?

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Re: Lost Faith In Spektrum
« Reply #73 on: May 22, 2018, 08:06:44 AM »
I did see someone recommending using supercapacitors for this on another forum. He did the calculations and used 3 in series to get a suitable voltage and needed around 5F capacitors to store enough charge to cover a low voltage. His system did need an initial connection through a resistor to reduce the charging current to a safe value similar to that used in high voltage ESCs.

The capacity isn't the issue - it's the voltage/charge characteristics of capacitors. Capacitors are not batteries and their voltage is a function of the percentage charge they hold. So if you want a capacitor to hold a voltage above 5v it needs to have been charged to a voltage well above this beforehand. In this case the capacitor is claimed to be holding the voltage above 3.3v plus the drop-out voltage of the regulator which is (as phil pointed out) not a low value in specky receivers. So a capacitor which is only charged to 5v is somehow expected to hold the voltage above ~4v against current demands in whole amps.

The numbers don't add up.

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Re: Lost Faith In Spektrum
« Reply #74 on: May 22, 2018, 10:00:21 AM »
The numbers don't add up.

Phil - I've been mulling this while driving from the hotel, but it's been >35 years since I actually worked as an electronic engineer so I'm not exactly current [sorry!].

But if I WAS looking to use a capacitor to hold the voltage up would I be able to improve the effectiveness by stacking the cap on top of a (say) 3v zener? It would still need to be a 'kin enormous cap to supply more than a few millicoulombs of course, but this is just a thought exercise.

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Re: Lost Faith In Spektrum
« Reply #75 on: May 22, 2018, 11:37:13 AM »
these days it's not "interference!" It's "brown out!"

Brownouts are the fault of the installer not the receiver.

It must be close to ten years since Spektrum released the QuickConnect firmware for their early DSM2 receivers and people still go on about Spektrum brownouts.

Does anybody know if Futaba ever fixed their zero GUID problem or if Multiplex ever got around to developing a 2.4GHz system or if FrSky ever released any decent 328 1.8.1 compliant firmware?

Steve

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Re: Lost Faith In Spektrum
« Reply #76 on: May 22, 2018, 14:35:21 PM »
Brownouts are the fault of the installer not the receiver.

It must be close to ten years since Spektrum released the QuickConnect firmware for their early DSM2 receivers and people still go on about Spektrum brownouts.

Does anybody know if Futaba ever fixed their zero GUID problem or if Multiplex ever got around to developing a 2.4GHz system or if FrSky ever released any decent 328 1.8.1 compliant firmware?

Steve
More likely the fault of the pilots thumbs...

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Re: Lost Faith In Spektrum
« Reply #77 on: May 22, 2018, 21:05:19 PM »
Brownouts are the fault of the installer not the receiver.
Brownouts are the fault of the installer not installing an adequate power supply, or the system suddenly drawing an unexpectedly high current  :af
It must be close to ten years since Spektrum released the QuickConnect firmware for their early DSM2 receivers and people still go on about Spektrum brownouts.
Quickconnect has nothing to do with it Steve, at the point Quickconnect comes into play you're recovering from a situation that wouldnt have happened with an adequate power supply.  QC comes in after the horse has bolted, the brownout has already happened. Like the 5-cell pack, its not really an answer to the actual problem.  Its a fact that many non-technical people first came across the term 'brownout' when they started to use Spektrum equipment, and consequently they believe its a Spektrum term and are unaware of its general use. Few actually understand the term.
Does anybody know if Futaba ever fixed their zero GUID problem
yes, they fixed it immediately it was discovered, many years ago.
...or if Multiplex ever got around to developing a 2.4GHz system
... not sure what you mean here Steve, all current Multiplex trannies are 2.4g???
...or if FrSky ever released any decent 328 1.8.1 compliant firmware?
what problems are you having Steve?

The capacity isn't the issue - it's the voltage/charge characteristics of capacitors. Capacitors are not batteries and their voltage is a function of the percentage charge they hold.
This is true of course Pete but in the case of Supercaps, the discharge curve is massively flattened when compared to the 4700uF Spektrum capacitor. Whilst the fall in voltage is worst as we're at the steepest part of the curve, the huge capacity significantly extends the graph horizontally so a charged supercap could work - its just the same as any decoupling cap on any circuit board, but on a massively bigger scale.
The problem is that the supercap self-discharge is very high, so it would almost always start out fully discharged. Switching on the rx in this state would effectively short the supply as the capacitors esr is very low, and its voltage zero.  If you tried to avoid this by limiting the charge current, it could take tens of seconds to charge.  If you recall I posted the maths for the 4700uF but a supercap brings a new perspective given proper control circuitry - albeit heavier, larger and more expensive than a decent battery!
Cheers
Phil

PS forget the zener idea  :af
« Last Edit: May 22, 2018, 21:24:57 PM by Phil_G »

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Re: Lost Faith In Spektrum
« Reply #78 on: May 22, 2018, 21:26:35 PM »
Fair enough - we didn't have supercaps the last time I practices as an electronic engineer!

I suppose you'll now tell me that brown-outs are no longer a matter of diode flutter from stray resonances in the IF fructode descramulators? I'm sure that the problem would go away if they just used the traditional approach using mudulition across a marycap with daractor clamping, but what would I know...

 ::)

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Re: Lost Faith In Spektrum
« Reply #79 on: May 22, 2018, 21:49:43 PM »
Quickconnect has nothing to do with it

QuickConnect has everything to do with the Spektrum brownout myth. The problem was not that pre-QuickConnect Spektrum receivers reset at 3.5V, it was that they could take seconds to reacquire the signal after rebooting.

yes, they fixed it immediately it was discovered, many years ago....

not sure what you mean here Steve, all current Multiplex trannies are 2.4g???

what problems are you having Steve?

Whoosh.

Steve


 

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