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Old Dec 20, 2012, 06:13 PM
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USA, KY, Louisville
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2.4 antennae and whiskers and count

Hi Guys,
It looks like you are the guys to answer this question but its one that drives me nuts.

Spectrum RX's have short 31mm whiskers on their RXs and Remotes....well some of them! :-(

They have one RX that has one long antenna and one of the 31mm sticking out the other side. I am not a newbie, actually have flown RC Sailplanes more places on Earth than anyone else in the galaxy..and I know a bit about this kind of thing,,, but not enough to break thru the double talk and misdirection.

Some of their remotes have only one of the long antenna (sheilded wire with 31mm whisker sticking out its end).

The Orange Spectrum compatibles only use one short whisker, OR now have one of the shielded longer antenna. The shield appears to be grounded inside the RX.

What the heck!!!!???

Okay that's part 1 of my question...I'll ask part 2 in my next post.
Thanks
GordySoar@aol.com
Gordy in Louisville Kentucky
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Old Dec 20, 2012, 06:19 PM
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My second question...How can "full range" not be full range?

The Spectrum 7 and 9 channel fairly pricey RX's will not operate a model unless a remote is plugged into them. They say its to provide extra 'reception' reliability.

Receivers receive, if the TX sends its signal for miles, a receiver out to hear it.

Spectrum now offers a 4 channel RX, no remote with two whiskers, and call it Full Range for $39...yet their 7 and 9 can't operate with out a seperate remote ...and the 9 has two RX's already inside its case.

I realize about the scare tactic....(well you wouldn't want to chance losing an expensive aircraft would you?)

Why don't the Orange RX's need two antenna, or remotes to be Full Range....

both the new 7 Orange and 9 Orange have remote ports....

What does Full Range mean if it doesn't mean full range?

Thanks
Gordy
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Old Dec 20, 2012, 07:19 PM
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Australia, WA, Drummond Cove
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Quote:
Originally Posted by Gordysoar View Post
Hi Guys,
It looks like you are the guys to answer this question but its one that drives me nuts.

Spectrum RX's have short 31mm whiskers on their RXs and Remotes....well some of them! :-(

They have one RX that has one long antenna and one of the 31mm sticking out the other side. I am not a newbie, actually have flown RC Sailplanes more places on Earth than anyone else in the galaxy..and I know a bit about this kind of thing,,, but not enough to break thru the double talk and misdirection.

Some of their remotes have only one of the long antenna (sheilded wire with 31mm whisker sticking out its end).

The Orange Spectrum compatibles only use one short whisker, OR now have one of the shielded longer antenna. The shield appears to be grounded inside the RX.

What the heck!!!!???

Okay that's part 1 of my question...I'll ask part 2 in my next post.
Thanks
GordySoar@aol.com
Gordy in Louisville Kentucky
Gordy
The only functional part of the antenna is the unshielded bit on the end. You can have a long section of shielded cable between the receiver and the antenna. This is done on some receivers so that you can place your antenna in a convenient place away from interference. Frsky actually offer a range of length antennas up to 60cm that could be used on any 2.4g receiver. Each of those antennas has the same 30mm unshielded at the end that is the real antenna.

Tig
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Old Dec 20, 2012, 07:41 PM
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Australia, WA, Drummond Cove
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Quote:
Originally Posted by Gordysoar View Post
The Spectrum 7 and 9 channel fairly pricey RX's will not operate a model unless a remote is plugged into them. They say its to provide extra 'reception' reliability.

Receivers receive, if the TX sends its signal for miles, a receiver out to hear it.

Spectrum now offers a 4 channel RX, no remote with two whiskers, and call it Full Range for $39...yet their 7 and 9 can't operate with out a seperate remote ...and the 9 has two RX's already inside its case.

I realize about the scare tactic....(well you wouldn't want to chance losing an expensive aircraft would you?)

Why don't the Orange RX's need two antenna, or remotes to be Full Range....

both the new 7 Orange and 9 Orange have remote ports....

What does Full Range mean if it doesn't mean full range?

Thanks
Gordy
Your Spektrum receiver will work without the satellite receiver but I wouldn't recommend it because it adds security of the signal.

There are a few reasons for the satellite receiver. It adds another point that the signal can be received so that if the main receiver loses its signal due to being blocked, by the motor for example, there is no interuption to the data transmission. It also allows you to have the second receiver orientated in a different direction. Ideally the satellite receiver antenna should be orientated at 90 to the main receiver's antenna. This is because their ability to receive out in the direction of the tip of the antenna is much reduced. They rely on the signal crossing the antenna. That is also why on 2.4g transmitters the antenna has an elbow in it. It is meant to be bent so that you don't point it directly at your model and lose signal strength.

Radio signals aren't as simple as just "being in the air around the transmitter" they are a wave that is oriented in a direction or directions. With the 2.4g these days this is even more so because the higher frequency means that the radio waves are less able to bend around objects. That is why 2.4g is able to be blocked by your own body and sometimes (with some radios) simply turning your back on your model can cause it to lose signal.

Full range is more to do with the power output of the transmitter than the orientation and type of antenna. Even on the Orange full range receivers you should use a satellite receiver in my opinion. It just adds security to your link. Funnily if you open up an Orange receiver you will find that there is actually two antenna connections but only one antenna is installed. I'm unsure if there are actually two transmitter circuits for redundancy however. On the high end Spektrum receivers I believe that they have two receiver circuits (someone can correct me here if I am wrong). Its all about having multi-receiving paths to the model to improve security of the link.

I'm only an amateur in electronics so this is just a layman's explanation and may be not technically exact but I think it tells the story. I'd be happy if someone gave a more in depth explanation.

Cheers
Tig
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Old Dec 20, 2012, 08:40 PM
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Okay ready for an actual answer

Hi Tig,

Thanks for your heart felt reply but clearly you didn't read what your wrote.

You said that because a RX is in range of a TX doesn't mean it can hear...because of waves or shapes...sorry while that is a fact on an oscilliscope but on the flying field, its baloney.

I would pay you $100 to stand on a flying field, gyrate and angle til one of our RX's lost signal. (no disrespect meant :-)

Then you state that its not the RX its the TX (Full range is more to do with the power output of the transmitter than the orientation and type of antenna. Even on the Orange full range receivers you should use a satellite receiver in my opinion.)

WHY would you need an satelite RX? The majority of 2.4 RC systems in the entire world only use one RX ...in anything.

I posted my questions not because I'm lonely and looking for some casual conversation, or platitudes about the security of it all. A Full RANGE RX should work, not maybe work work if you spend even more money and care.

And your body won't block the signal enough (unless in range check mode) to ever lose the signal....keep in mind I fly high performance sailplanes, so I fly a lot farther away than any power guy, (I've done three 8 hour flights with out a motor).
And I have flown RC sailplanes more places in the world than anyone else on Earth...so kind of know all the things you offered.

I also fly giant gas, electrics, and even a turbine, 90% of what I fly is made of carbon. I wrote part of the book on 2.4 installs in carbon fuses....

And no a 7 channel Spectrum and 9 channel will not work servos without a satelite installed.

Tig I appreciate your desire to be helpful but its time we got some real answers...like to your own question
..."Funnily if you open up an Orange receiver you will find that there is actually two antenna connections but only one antenna is installed".

In fact, the only RX's that have two RX's in the same case is the 9channel JR and Spectrum (921 and 9300)...two RX's but only two whiskers...

Guys Please skip over this part, go to my original two questions and give us some idea of what the heck are these suppliers pulling with their RXs and their RX's whiskers :-)

Gordy
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Old Dec 20, 2012, 09:04 PM
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You obviously believe you know more about all this than me and believe that I don't know anything
Sorry I wasted your time
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Old Dec 20, 2012, 09:27 PM
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One way to read it

Hi Tig,
Clearly your feelings have been hurt, but this question isn't about feelings, its about answers.

I just got off the phone with the fella at RC Model Reviews, (he assured me that the world didn't end for him since its already after 12/21 (hope my reply didn't end yours Tig :-).

He said its all about the RX design....some use the wiring inside to make up the back end of the antenna, some use the shielding, some don't need it anymore..that it was part of the original 2.4 design considerations.

Orientation DOES have a lot to do with the signal and the ability of the RX to capture it....so Tig was correct....but that idea goes out the window since our models and the RX's inside aren't static, they are in constant re-orientation as they move through the sky. And for us sailplane guys, we don't have motor's to interfere and for the most part we have the whiskers sticking outside the fuselages so that the are in constant view of the TX antenna (visual)...and waggling around so again orientation isn't an issue.

A 2.4 wave length is really short (I'm guessing 31mm long), so the idea of remotes is to capture either the original signal or the bounced signal, since both are happening simultaneously.

This is not about one brand or model RX working or not working, they are working now days....In the end I am still sitting in the same spot on the subject...we trust the RX's that come with only 1 whisker and no remotes, and don't trust the ones that come with two whiskers without using remotes? We don't trust that an RX that says Full Range is actually Full Range unless we have remotes....

Gordy
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Old Dec 20, 2012, 09:57 PM
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My feelings aren't hurt as you put it.

However I don't like people wasting my time because they don't listen or understand.

I'm glad you were able to believe Bruce even though he obviously told you pretty much the same story. At least one person is able to get it through to you at least a little bit
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Old Dec 21, 2012, 02:34 AM
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United Arab Emirates, Dubai
Joined Sep 2006
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Quote:
Originally Posted by Gordysoar View Post
WHY would you need an satelite RX? The majority of 2.4 RC systems in the entire world only use one RX ...in anything.
You got the technical answer. 2.4GHz is sensitive to fades (drops in signal due to reflections adding or subtracting themselves, cancelling out each other at times), to obstacles (wing, battery, even just a carbon rod in the structure happening to be between the transmitter and receiver antenna), to cross-polarization (TX and RX antennas perpendicular to each other = huge loss), and to the inherent "holes" in sensitivity on the axis the antenna is pointing.

This means that you WILL have times in flight where you'll have sudden losses of signal. Having another antenna it will be placed elsewhere, which means it usually won't be in the fade when the first one is (even a few cm are enough with these wavelengths), might not be behind the same obstacle, and as it won't be parallel to the first one cross-polarization and hole are taken care of in most cases.

Actually Spektrum had the kind of weird idea to put the 2 antennas in parallel on their receivers and satellites, which means that they're not so efficient at dealing with cross-polarization and the sensitivity hole, which is probably why they made the whole satellite thing as you can mount the entire sat in a different orientation.

But anyway, nothing is either "perfect" or "useless". A receiver with just one antenna will work in most cases. One with 2 will still get a signal in some cases where the other one loses it. A receiver with 4 antennas will still get a signal sometimes when the other 2 don't... etc, you can go up to the Spektrum AR12120 to which you can connect up to 4 satellites if you feel like it.

Nothing's gonna ever be perfect. You can just add some and gain more reliability. Whether it's needed for your case or confidence is up to you. What the manufacturer decides is an acceptable risk of drops when they sell you a receiver with ot without satellite is also kind of arbitrary.

Quote:
Originally Posted by Gordysoar View Post
I wrote part of the book on 2.4 installs in carbon fuses....
Not wanting to sound offensive, but if you wrote a book about antenna installation without understanding these concepts I certainly wouldn't buy it

And by the way, this whole matter is completely off topic for this "DSMX hacking" discussion
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Old Dec 21, 2012, 05:19 AM
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Originally Posted by RW9UAO View Post
it`s a good question, how long time we need to go to failsafe? 1 sec? 2 sec? is go to failsafe values softly or hardly? if softly, what time need to change value? my heli ESC do not love fast off and go back, main gear will be broken.
many questions for receiver software author.
A hold occurs when 45 consecutive frame losses occur.
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Old Dec 21, 2012, 05:23 AM
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A hold occurs when 45 consecutive frame losses occur.
Where did you get this info from?
...and is that 45 frame in channel search mode?
...if not, how meny frames have to be lost to start the channel search?
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Old Dec 21, 2012, 05:25 AM
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From AR8000 manual.

"Frame loss—represents simultaneous antenna fades on all attached receivers. If the RF link is performing optimally, frame losses per flight should be less than 20. A hold occurs when 45 consecutive frame losses occur. This takes about one second."

I think that hold is failsafe initialization. Why you need to start channel search before failsafe initialization?
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Old Dec 21, 2012, 07:10 AM
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Thanks!

Quote:
Originally Posted by vlad_vy View Post
I think that hold is failsafe initialization. Why you need to start channel search before failsafe initialization?
If it goes out of sync (which it shouldn't btw), then it won't find it again, if the receiver doesn't try to match channels again.
However the only way I think it could happen on rx or tx restart (or some sw glitch perhaps).
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Old Dec 21, 2012, 03:41 PM
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I have implemented dsm telemetry support in Deviation, it only works with <= 7 channels. I am not sure there is actually sufficient time to receive a telemetry packet when using 8 or more channels in Deviation. I will need to do some more experimentation to see if I can squeeze it in or not.
I only have 4 sensors supported: RPM (untested), external voltage, external temp, internal voltage.
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Old Dec 24, 2012, 08:30 AM
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United Kingdom, England, Birmingham
Joined Mar 2011
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Quote:
Originally Posted by RW9UAO View Post
at now i have worked code for:
dsm2/dsmX 10/11 bit 11/22 ms receiver/transmitter and all telemetry, like GPS, S-sensor, current, powerbox, etc...

i have one question: why Orange not release cheap dsm2 telemetry and cheap dsmX rx/tx (not for last bugged odd job with 10 fixed IDs)? HorizonHobby promised to kill oranges?
great work guys but its difficult to implement especially if you dont know what you're doing (aka me)

In summary is there now a fix for the OrangeRX DSMX/DSM2 2.4Ghz Transmitter Module (JR/Turnigy compatible) http://www.hobbyking.com/hobbyking/s...Product=24656?
if there is how to flash the thing so I dont need to use the reset button (or could one write a guide how to compile the code and create the hex (or whatever) file to update the firmware ?
apologies for the lame terms
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