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Disabled/Veterans Radio Control system

JasonK

Master member
#21
I was just reading a spectrum manual and it specifically calls out setting up and _testing_ the loss of signal behavior of the receiver as part of proper setup/testing.

I don't know what radio system the confused person was using, but it it is spectrum, they are specifically violating the best practices set out by the manufacturer of their radio system.
 

Hai-Lee

Old and Bold RC PILOT
#22
I was just reading a spectrum manual and it specifically calls out setting up and _testing_ the loss of signal behavior of the receiver as part of proper setup/testing.

I don't know what radio system the confused person was using, but it it is spectrum, they are specifically violating the best practices set out by the manufacturer of their radio system.
His comprehension seems to be suspect because he has stated that in all the manuals that he has read he has never read where powering up a receiver first is safe. He is a devoted Spektrum user. He obviously must not have read a manual, (if his statement is true), since 2007 which is the earliest manual reference, (I can find), for the operation and handling features of Smartsafe.
Actually it is more like selective reading in that he searches the document for what suits his views but fails to read or understand anything that does not suit his needs!
A real piece of work!
 

Hai-Lee

Old and Bold RC PILOT
#23
Update:
It has been a while and the proof of my assertions continues to grow.
What I did notice though is that my reasoning was either too technical for most or I made assumptions on the basic knowledge of other RC users,
To correct my lack of adequate explanations I tried to write an explanatory note or technical guide for those who did not understand my previous posts.

Here is a cut and paste of the document text;

2.4 GHz Radio Control
Anyone can do a simple internet search and get accurate information on how the radio control systems of years gone by operate or operated as well as their failings and shortcomings. However if you were to do the same search for information relevant to modern digital ISM band 2.4 GHz digital radio control systems you may find actual/factual information very difficult to locate and even find a large amount of dangerously inaccurate information and flawed opinions.


Microprocessors are now the norm in modern radio control systems and yet the way the transmitter and receiver communicate seems to be almost secretive. I have contacted manufacturers directly only to find that the engineering teams are impossible to contact directly and the company representatives have shown a lack of any real technical knowledge, (or understanding), often actually providing information that can be easily proved to be false, (and sometimes very wrong and actually dangerous).

This little article is just to help fix a few obvious misunderstandings as to how the modern digital radio control systems actually communicate and will not be going deeply into the various protocols or the individual operating firmware used, (as loaded in the OEM equipments). If this article improves your understanding and possibly prompts you to do a little research and investigation, for your own safety, then it has been of some value.


It appears that the article in full is far too large for the forum to accept. For those who wish to have a quick read I have added the PDF version of the full article for those who may wish to download and test the information contained therein.

Some many have questions or wish to raise individual issues that they may have experienced and I welcome their input or comments.

As usual I wish for everyone to "Have Fun"

P.S.

Addendum added - 05 August 2021.

Have fun!
 

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Piotrsko

Master member
#24
Awesome write up, no surprise as usual, but perhaps still a wee bit too technical for most. Very adequately explaining the subsystems, but I have prior training and it still had issues following some chapters. Not a critique, but the data IS technical and headache provoking. Might have been worth a short paragraph on how the older equipment worked, then juxtapose the methodology to see why the new stuff is safer?
 

Hai-Lee

Old and Bold RC PILOT
#25
Awesome write up, no surprise as usual, but perhaps still a wee bit too technical for most. Very adequately explaining the subsystems, but I have prior training and it still had issues following some chapters. Not a critique, but the data IS technical and headache provoking.
I did have a bit of a problem with the term "Channel" simply because it can be used to describe the radio operating frequency as well as the actual receiver outputs to the servos or ESC.

Thank you for the feedback and I am waiting on the feedback from the engineering team used by an aeromodeller magazine to see if they require the document to be simplified.

Have fun!
 

Piotrsko

Master member
#26
I did have a bit of a problem with the term "Channel" simply because it can be used to describe the radio operating frequency as well as the actual receiver outputs
well they both were considered channels by defination back In the 27 mhz days and it stuck. Since the current hardware uses blocks where the position/value of the word bits determine the servo response, they are still channels by that defination although nowadays that term is obsolete and replaced by packets, I believe.
 

Hai-Lee

Old and Bold RC PILOT
#27
The communication is performed in packet format but the individual parts of the transmitted and received packet are for different purposes including the control of the servo outputs of the receiver.

If I rewrite it in the near future I may refer to the receiver channel outputs as the "receiver control outputs" instead.

Actually the important message in the article is that FCC Part 15C means that a transmitter is not free to transmit at all times, and that a receiver will only supply control outputs that the transmitter commands or what the receiver is programmed to perform via failsafe.

I chose to eliminate the details on antenna effects on the reliability of communication which was over half of the first edition.

The remainder is just an overview of the basic spread spectrum requirements in layman's terms, (as best I could use them).

Have fun!
 

Piotrsko

Master member
#28
"Actually the important message in the article is that FCC Part 15C means that a transmitter is not free to transmit at all times, and that a receiver will only supply control outputs that the transmitter commands or what the receiver is programmed to perform via failsafe."

^^^^^^^^^^ That comment appears to have summarized your arguement with turning on or off transmitter function in sequence exquisitely in addition to including the invocation of a higher authority
 

Hai-Lee

Old and Bold RC PILOT
#29
WARNING!
You now possess knowledge that some seem to think is either blasphemy, related to the occult, or something akin to dabbling in black magic.

You are now in a very small, (minuscule), minority and could suffer persecution the same as Marco Polo, Galileo, and prophetic others were, especially when the proclaimed different beliefs are different to those in political and administrative power within the club scene and the national associations. The "Flat Earth Society" still exists it is just that they now are self appointed, and empowered, experts in radio control!

Mind you I have yet to find any attempt at explaining the operation of the modern radio products, in the product manuals, that is even close to the actual truth, excepting possibly Horizon Hobby/Spektrum but even the you need an amount of base technical knowledge or understanding just to be able to read between the lines of what they state and claim.

I may add your suggested Analogue Vs Digital transmitter and receiver operating differences explaining why the "Tx on first" requirements given in so many inaccurate manuals, (all Chinese equipment unfortunately), is actually a dangerous requirement especially for those who have no technical knowledge. It will be labelled as an "addendum".

Please also consider the effects of decreasing the available radio channels caused by leaving all of the digital transmitters powered up at the same time especially in a residential club setting.

Have fun!
 

Piotrsko

Master member
#31
Yes, the disadvantage of free thought: always branded a malcontent (synonym of lower human exhaust port). I wear the badge with honor and nowadays promote it.

One slight correction that may or may not be applicable is that in the US we spell bight as bite. It took me a while to cipher out the meaning. Otherwise in the vernacular : You nailed it, dude. particularly the ancient analog dogma.

Let the club people forever wonder why their hardware works erratically at meetings and events. They deserve that.
 
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Hai-Lee

Old and Bold RC PILOT
#32
Yes, the disadvantage of free thought: always branded a malcontent (synonym of lower human exhaust port). I wear the badge with honor and nowadays promote it.

One slight correction that may or may not be applicable is that in the US we spell bight as bite. It took me a while to cipher out the meaning. Otherwise in the vernacular : You nailed it, dude. particularly the ancient analog dogma.

Let the club people forever wonder why their hardware works erratically at meetings and events. They deserve that.
Sadly here to knowingly allow someone to create a hazard and then cause someone an injury or result in property damage is legislated such that you effectively are allocated equal responsibility even if that person is ignorant of the hazard. It really sucks big time.

For those forum users who would like a little more about the digital radios we use here is a link to a basic information video which may give a little more technical explanation.

Just a little bit of further consideration - all numbers transmitted are in binary where a number such as 1024 is equivalent or represented in 10 data bits only and so 6 control channel numbers if based upon 1024 divisions would take only 60 data bits excluding the radio GUIDs any operating data transfer and of course the receiver output control slot information.

The data channel identifiers could be covered 3 data bits each and so this would amount to an extra 18 bits plus channel separators

The GUIDs are normally upto 6 bit decimal numbers but can be reduced to either a number of binary encoded decimal numbers or as a straight binary expression of the GUID as a 6 digit decimal number expressed in binary format.

All of this means is that the transmission of what appears to be a massive amount of information is actually able to be expressed in only a few hundred bits of binary data.

Have fun, (and buy in some paracetamol - it helps with the headaches generated by this topic).