Notices
RC Radios, Transmitters, Receivers, Servos, gyros Discussion all about rc radios, transmitters, receivers, servos, etc.

2.4 - Why Are They Failing?

Old 01-12-2011, 09:04 PM
  #176  
dirtybird
My Feedback: (5)
 
Join Date: Jan 2002
Location: San Tan Valley, AZ
Posts: 5,768
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: Zor


- dirtybird

Maybe if you get some more modern equipment you won't have to wonder about so many things.
A simple A/D converter connected to a PC will be much more useful than that old junk you have.
You can capture a waveform and study it. You can see transient waveforms that will never show up on that old tube stuff.
dirtybird,

I think that as a gentleman you should not write this kind of posting.

You just have an obsession against some good quality old, well preserved and excellent quality instruments. .

My oscilloscope works perfectly well and display waveforms with direct coupling amplifiers up to 10 megahertz. That is well beyond our requirement. .

We are dealing with nothing shorter than miliseconds which is only one ( 1 ) kiloherz or 1,000 hertz.
The scope can displays 10 Megahertz which is 10,000,000 hertz.

We are observing electrical waveforms in the order of volts on an instrument that can display 3 milivolts at full screen up to 300 volts and higher with low capacitance probes.

I do not mean to be rude to you but you only displayed your lack of knowledge of this type of electronic equipment.

You really need to learn more.

Knowledge of how our systems function is much more valuable to readers than being a ''blabermouth'' about my test equipment that functions very well.

I invite you to do as I did and show us in pictures the waveforms involved in our control systems and your setup .

If you cannot do that then perhaps you should refrain from posting what you wrote which is completely erroneous and out of the attitude of this forum.

I feel sorry for the readers that have to put up with the garbage you posted.

Zor
Since you are now reduced to personal attacks this will be my last post.
I have a Leader 526 Oscilloscope and a Tektronic 502 DMM Oscilloscope, both of which have considerably more capability than 10 mhz. But they are not a storage oscilloscope and that makes it very hard to capture transient information.
I have a 10mhz A/D converter but it needs a parallel port which the latest computers no longer have.
So I can't provide the waveforms you would like to have.
I have current vs torque plots on several servos that I tested for an article I wrote on servo capabilities in 2005. One of the servos is the Hitec 5955. If you would like to have a copy PM me with a check for $100/plot.
$100/plot may seem steep but it is actually a bargain as I used to charge $60/hr for contract work, and I worked at least 3 hours on each plot
Old 01-12-2011, 09:22 PM
  #177  
Loopman
Thread Starter
My Feedback: (195)
 
Join Date: Feb 2002
Location: Duluth, GA
Posts: 788
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?

Guys,
I have gained alot of fresh knowledge here and I think that for the most part this has or continues to be a hot topic. I do not think we should bash anyone on any forum as everyone's ideas have merit. Thank you all for contributing to this thread. As for my original direction on this I will restate that we bought into 2.4 in general because we wanted that magic bullet that would make us like "Superman" when it came to frequency impregnability, however I think that for all the good 2.4 has done we are still seeing some Kryptonite seep in every now and then. The gremlins are still with us! I can say without a doubt that the planes I saw (mentioned in the original post) had every conceivable fail-safe and they still succumbed to the same old problems that haunt us with all of our efforts be it 2.4, 72mhz or even Ham Band. I will remove my use of 2.4 to my park flyers and foamies and I'll continue to take my chances with PCM on my larger planes, JMHO! I say to everyone here; "To each his own" and I say that with respect to everyone's personal choices.

Happy Flying!

Loopman
Old 01-12-2011, 09:34 PM
  #178  
rcfan450
Senior Member
 
Join Date: Dec 2006
Location: Heber, UT
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: Loopman

Guys,
I have gained alot of fresh knowledge here and I think that for the most part this has or continues to be a hot topic. I do not think we should bash anyone on any forum as everyone's ideas have merit. Thank you all for contributing to this thread. As for my original direction on this I will restate that we bought into 2.4 in general because we wanted that magic bullet that would make us like ''Superman'' when it came to frequency impregnability, however I think that for all the good 2.4 has done we are still seeing some Kryptonite seep in every now and then. The gremlins are still with us! I can say without a doubt that the planes I saw (mentioned in the original post) had every conceivable fail-safe and they still succumbed to the same old problems that haunt us with all of our efforts be it 2.4, 72mhz or even Ham Band. I will remove my use of 2.4 to my park flyers and foamies and I'll continue to take my chances with PCM on my larger planes, JMHO! I say to everyone here; ''To each his own'' and I say that with respect to everyone's personal choices.

Happy Flying!

Loopman
I think I have decided to do the same thing as you Loopman. I'll take my chances with 72 on my big stuff and fly my little stuff on 2.4. I flew for several years on PCM and only had one glitch (it was a battery issue, not PCM). I've had several issues with 2.4 on my big stuff and I believe it mostly deals with rx placement (it's not brownout issues, I have some serious power and the rx has light indicators that tell me if it reboots, it never has). Seems ridiculous to me to guess at placement and take my chances over and over when all I had to do before was plop in a PCM and not worry at all. I don't want to fly nervous anymore. PCM all the way baby!

(PS, I live in the boonies, no one else flies around here so I don't have to worry about inteferance issues).
Old 01-12-2011, 11:06 PM
  #179  
Zor
Banned
 
Join Date: Feb 2009
Location: Ontario, ON, CANADA
Posts: 3,524
Likes: 0
Received 1 Like on 1 Post
Default RE: 2.4 - Why Are They Failing?


Posted by dirtybird

Since you are now reduced to personal attacks this will be my last post.
I have a Leader 526 Oscilloscope and a Tektronic 502 DMM Oscilloscope, both of which have considerably more capability than 10 mhz. But they are not a storage oscilloscope and that makes it very hard to capture transient information.
I have a 10mhz A/D converter but it needs a parallel port which the latest computers no longer have.
So I can't provide the waveforms you would like to have.
I have current vs torque plots on several servos that I tested for an article I wrote on servo capabilities in 2005. One of the servos is the Hitec 5955. If you would like to have a copy PM me with a check for $100/plot.
$100/plot may seem steep but it is actually a bargain as I used to charge $60/hr for contract work, and I worked at least 3 hours on each plot
Dirtybird,

Thanks for your last previous posting.
Your money deal is hilarious ; very funny.

As I wrote, I did not want to be rude to you but you made the first move by attacking my beloved equipment that works very well and which I used to post information for all readers of this forum.

Your comments implied clearly that I did not know what I was doing, that my oscilloscope could not show the waveform properly and you referred to it as "JUNK".

You seriously hurt my feelings with your posting and the choice of words.
I made an honest effort to provide some data and back it up with pictures.

Now you present excuses for not being able to come out withthe datafrom the more sofisticted instrumentaions you are listing..i am not surprised .

I do not degrade others good efforts even when I cannot agree with their presentation knowing the good efforts they made within their capabilities.

You had the opportunity toshow actionand you made your choice which are just excuses.

What are we to believe ?

I have no incentive to carry this discussion any further.

My best regards go to all readers.

Zor

Edit by Zor
P.S.: The name of the oscilloscope company is "Tektronix"
Old 01-13-2011, 01:56 AM
  #180  
rambler53
Senior Member
My Feedback: (494)
 
Join Date: May 2004
Location: Palm Bay, FL
Posts: 1,437
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?

ORIGINAL: FLPilot

Perhaps, we need to chill,

and use one of these for awhile.............
What I like about these units, are they're very compatible with most models, and it really feels good in your hands. It's not too heavy, and yet, it's rugged. It's very easy to use, although, I guess someone not being careful, can get the elevator reversed. [X(]

I had an old vacuum tube O scope back when I was a tech in 1982. It took awhile to warm it up, and let it stabilize. It kept the room nice and warm though. It also was a Tektronix. Astro Too Surplus Electronics has one on the shelf for $75 in Melbourne FL is anyone wants to add it to their work bench. (It has to be a really strong work bench.) I don't know who calibrates them anymore?
Old 01-13-2011, 02:41 AM
  #181  
rambler53
Senior Member
My Feedback: (494)
 
Join Date: May 2004
Location: Palm Bay, FL
Posts: 1,437
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?

ORIGINAL: mike31

Go back to AM. Nobody there!
You know, I tried a $10 AM radio on a old banged up Stick 40 I didn't care if it augered into the ground or not, and it did pretty well. I liked how the antenna stored inside the radio and it had it's own built in stand. It came with several planes I picked up from the same era. Seemed to be working fine for the man that owned those classics for many years. If AM can fly, imagine how well PCM modulation can. 72Mhz is solid and trusted for over 30 years? Before 2.4, that was the way to go. The learning curve for 2.4 cost some people a pretty expensive plane. It's always best to wait a little bit for the dust to settle on new technology. It's even better with an frequency empty board these days. If I flew competition and a sponsor threw one in with the hat and T shirt, I'd use even a Hitec. But, I pay out of pocket for my equipment. Got to love the cost advantage of 72 Mhz if you're on a budget. It's not obsolete in my book. It's a bargain. 700mah 4.8v batteries don't let me down. I never programmed an easier radio than a 9C.
$429 radio. Why? It doesn't have wifi, MP3, G3, play video, games, hold documents, sends email, has a 1.3 MP camera, hold 32GB, but it costs more than my kids itouch that does all of that and also has a touch screen. 2.4Ghz radios are ridiculously priced if itouch technology for my kids is more sophisticated than a radio that just sends and receives 2.4Ghz signals that I'm asking from a programmable radio to do. Open up a new radio these days and you wonder were all your money went.
Old 01-13-2011, 03:33 AM
  #182  
TimBle
Senior Member
 
Join Date: Apr 2010
Location: Cape Town, SOUTH AFRICA
Posts: 2,744
Likes: 0
Received 1 Like on 1 Post
Default RE: 2.4 - Why Are They Failing?

Frsky makes great products. I don't know of any unhappy users except that group on rcgroups who heard of a problem, never had one themselves and no want to rubbish something that works. Typical spoilt brat mentality. Is it so hard to believe that something that works can cost a quarter of what you paid for that Spek stuff that seems to provide fuel for much concern?
Old 01-13-2011, 05:02 AM
  #183  
jquid
Senior Member
 
jquid's Avatar
 
Join Date: Jul 2002
Location: st. charles, IL
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?



jquid,

What I wrote _ _ _
quote

One pic shows how I jammed the rudder at neutral position.




The pic where my hand is seen at the left is where I am holding the rudder at full deflection and letting the control stick return to neutral.
unquote

In one pic the rudder was held centered with the two rulers and I was applying full deflection.

In the other pic my hand was holding the rudder preventing it from gong back to center while he stick was returned to neutral.

On the way to full rudder I had 412 ma,
On the way to center I had 540 ma.
Ratio of currents is 1.31

The 1.31 is the interesting figure
Get it ? Do you see why it is interesting ?

Zor

[/quote]
Basically there is a higher current draw trying to return to neutral than there is from neutral to full, assuming the same force? One would think it would be the opposite. but I guess that is where the digital servos shine, is in the deadband of analogs for small corrections, which is important to heli fliers.


Did I pass ?
Old 01-13-2011, 05:58 AM
  #184  
JohnBuckner
My Feedback: (1)
 
JohnBuckner's Avatar
 
Join Date: Dec 2001
Location: Kingman, AZ
Posts: 10,441
Likes: 0
Received 10 Likes on 10 Posts
Default RE: 2.4 - Why Are They Failing?

ORIGINAL: FLPilot

Perhaps, we need to chill,

and use one of these for awhile.............



Hm I like mine better, encoding for three additional channels cept' maybe it ain,t freqency hopping
Attached Thumbnails Click image for larger version

Name:	Db84049.jpg
Views:	11
Size:	50.2 KB
ID:	1546843  
Old 01-13-2011, 06:25 AM
  #185  
The_Shark
Senior Member
 
The_Shark's Avatar
 
Join Date: Jun 2007
Location: Plainfield, IL
Posts: 7,163
Likes: 0
Received 1 Like on 1 Post
Default RE: 2.4 - Why Are They Failing?

first of all i run cars

i have had 0 issues with 72Mhz even in a part of my neighborhood i call the "dead spot" i have had countless runaways with 27Mhz, and one with my 2.4Ghz micro hellie- not major just a temporary glitch. however this "dead spot" trips up systems that have no issues in the house right by a running microwave and ozone generator, and it just KILLS the signal, to the point where i can be 5 feet away from the car and it still freaks.

there must be certain parts of the world that just have really bad interference, i almost think satellite dishes and cell phone tower frequencies throw them off.

unless you have a shielded wire or fiber optics running to the vehicle, nothing is 100%
Old 01-13-2011, 06:32 AM
  #186  
Zor
Banned
 
Join Date: Feb 2009
Location: Ontario, ON, CANADA
Posts: 3,524
Likes: 0
Received 1 Like on 1 Post
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: jquid



jquid,

What I wrote ___
quote

One pic shows how I jammed the rudder at neutral position.




The pic where my hand is seen at the left is where I am holding the rudder at full deflection and letting the control stick return to neutral.
unquote

In one pic the rudder was held centered with the two rulers and I was applying full deflection.

In the other pic my hand was holding the rudder preventing it from gong back to center while he stick was returned to neutral.

On the way to full rudder I had 412 ma,
On the way to center I had 540 ma.
Ratio of currents is 1.31

The 1.31 is the interesting figure
Get it ? Do you see why it is interesting ?

Zor

Basically there is a higher current draw trying to return to neutral than there is from neutral to full, assuming the same force? One would think it would be the opposite. but I guess that is where the digital servos shine, is in the deadband of analogs for small corrections, which is important to heli fliers.


Did I pass ?

[/quote]

Hello jquid,

Did you pass ?
Pretty close but not fully.

True ___there is a higher current draw trying to return to neutral than there is from neutral to full.
but it is not "assuming the same force".

A higher average current on the return does provide for a higher force.

You may possibly have thought that a rudder going back to neutal is helped by the force of the airstream and going from neutral toward full deflection would need more current in the servo to give more torque as the rudder goes against the airstream.

Then the rudder would need less torque from the servo on its way back to neutral.

The above is what we can expect when the model is airborn and likely what does happen.

However in my experimentation there is no airstream and the current readings are opposite to what we could expect in actual flight.

What is then happening and how can it be explained ?

This is where the 1.31 current ratio is interesting. I myself had to try to figure this out.
I first wondered why that difference in current readings since there was no big wind on my dining room table .

The thought came into my mind that the servo is trying to go to a position determined by the transmitter stick. The position of the Tx stick is telling the servo "Hey you come to my position based on the width of the signal pulse my buddy receiver is feeding you".

You "servo" darn well know that if the pulse is 1.5 milisecond you stay in the middle.
When the signal pulse is 1.3 ms you go to the set full travel in one direction or the other direction depending on servo reversal If I would reverse the servo setting on my Tx you would have got a 1.7 ms series of pulses and you would have gone the other way.

OK ___all readers ___are you still here reading ? This is for you as well.

So I hold the rudder centered and give full left rudder with the Tx __you servo get a 1.3 ms pulses, you tell the battery "get off your 7.5 ma you are now supplying to my circuitry and give me 412 ma so I can go to the right. Hee Hee !!!

Oh! now says the rudder, I am being held at full right by hand and that fellow tells me to go full left.as I see a 1.7 ms command. You have to give me 540 mawith these wider plusessince I am trying to go full left.

540 / 412 = 1.31 like 1.31067961
1.7 / 1.3 = 1.31 like 1.30769231

Now let us not split hair on the precision of the ammeter reading or the accurcy of the transmitter pulses as decoded by the receiver.

I would not call that a coincidence.
I call that very interesting.

I am not teaching anyone in this forum and thread. I am only posting what I observe.

Have a great day all.
I just hope today will not degrade my hobby activity and refer to my good old stuff as "junk" .

Zor

Old 01-13-2011, 06:44 AM
  #187  
swede47
Member
My Feedback: (5)
 
Join Date: Aug 2005
Location: Grinnell, IA
Posts: 56
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?

I don't know what Nitro-Tom is smoking, but he needs to back off. All I did was to post a link to RCModelReviews about a GUID interference with a FrSky module and jumps on me. Somehow he's twisted it all around and has me flying a $3,000 model with a FRSky 'clone' RX. I have neither. I use some 72 and some 2.4 DX7.

So Nitro-Tom, you need to chill like FLPilot says.

S
Old 01-13-2011, 07:16 AM
  #188  
MinnFlyer
Senior Member
My Feedback: (4)
 
MinnFlyer's Avatar
 
Join Date: Apr 2002
Location: Willmar, MN
Posts: 28,519
Likes: 0
Received 8 Likes on 8 Posts
Default RE: 2.4 - Why Are They Failing?

Please resist the urge to curse, flame, degrade, insult or embarrass someone in your post. We encourage the free flow of your ideas, but believe that they can be communicated (and received) much more effectively if you keep things civil. If you have to vent, take it offline. We carefully monitor posts and will ban individuals who engage in offensive conduct within the forums. Thanks.

Read more: http://www.rcuniverse.com/forum/m_10...#ixzz1AvefLu8u
Old 01-13-2011, 08:27 AM
  #189  
Zor
Banned
 
Join Date: Feb 2009
Location: Ontario, ON, CANADA
Posts: 3,524
Likes: 0
Received 1 Like on 1 Post
Default RE: 2.4 - Why Are They Failing?


Original from Rambler53

I had an old vacuum tube O scope back when I was a tech in 1982. It took awhile to warm it up, and let it stabilize. It kept the room nice and warm though. It also was a Tektronix. Astro Too Surplus Electronics has one on the shelf for $75 in Melbourne FL is anyone wants to add it to their work bench. (It has to be a really strong work bench.) I don't know who calibrates them anymore?

My old scope has a 3 volts AC available on the front panel for calibration but since the line voltage can vary quite a bit I keep that in consideration.

When I use it and am concened with DC values and any superimposed AC and wish more precision I calibrae it using fresh C or D size alcaline Duracell as being 1.55 volts not loaded. 1.55 volts being the average reading of multiple cells read using 3 voltmeters. One digital voltmeter, aMicranta FET - VOM and a VTVM.

I also use 9 volts Duracell as being 9.45 volts for comparison. The 9.45 being the average reading of multiple batteries also read as above with 3 voltmeters.

These average readings are sufficiently accurate for any practical work I need to do.

Zor
Old 01-13-2011, 08:29 AM
  #190  
RamItOn
Junior Member
 
Join Date: Nov 2002
Location: Anchorage, AK
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?

Minn Flyer,

Not to be a whiner or tattletale, but it seems as though the main violator of your civility policy is dirtybird. If he has a disagreement with another member of RCU, he begins to condescend ("Maybe if you get some more modern equipment you won't have to wonder about so many things."). If his interlocuter's technical ability matches his own and can demonstrate it, dirtybird pretty much becomes an a***ole. I've had this experience with him some time ago regarding some problems with 2.4 GHz, and a quick scan of his posts reveals this is his M.O.

Thanks,

Tony
Old 01-13-2011, 08:35 AM
  #191  
MinnFlyer
Senior Member
My Feedback: (4)
 
MinnFlyer's Avatar
 
Join Date: Apr 2002
Location: Willmar, MN
Posts: 28,519
Likes: 0
Received 8 Likes on 8 Posts
Default RE: 2.4 - Why Are They Failing?

I think we should all just take it easy. We've gotten way off track here.

I don't think we need to hear anymore about whose scope can run faster or jump higher.

Now, can we get back on topic, or are we done with this conversation?
Old 01-13-2011, 09:28 AM
  #192  
jquid
Senior Member
 
jquid's Avatar
 
Join Date: Jul 2002
Location: st. charles, IL
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: MinnFlyer


Now, can we get back on topic, or are we done with this conversation?
Not sure.... I think we have concluded that multiple redundant systems on board batteries and Rx included are not a cause for (2) Aircraft at the same site having radio problems.
We have pretty much beat to death the current rates, and I do not think we are zapping it all from multiple batttery packs. Or are we?
Here is a thought, since we are talking about large aircraft, I am assuming that they are running multiple servos ganged together?
Any tests Zor on such a set up? I think it is Airwild that sells those servo trays, and arms.

Zor showed approx 500ma of current draw, but that was (1) lonely servo. How about ganging (3) together and testing the current draw? Are those in a harness or individually put into a seperate RX? Not sure, I do not fly the big stuff. Input guys?

So could we have 3X the current draw from a rudder? Now add elevator with multiple servos, and ailerons, etc?

We have also pretty much elimintaed any frequency close to the transmitter, such as another transmitter. So maybe it is a current spike of having 6-8 digital serovs move together could cause such an issue?

Thoughts appreciated.

Thoughts?
Old 01-13-2011, 09:58 AM
  #193  
Quikturn
My Feedback: (12)
 
Quikturn's Avatar
 
Join Date: Jan 2008
Location: West Des Moines, IA
Posts: 933
Received 6 Likes on 6 Posts
Default RE: 2.4 - Why Are They Failing?

I have an idea. How about spread spectrum/frquency hopping on 72mhz?

I know, one of the perks of 2.4 is to keep your antenna inside the airplane but I like to tape my antenna wires along to fuselage anyways. 72 is more proven and robust than 2.4 otherwise receiver placement wouldn't be so critical on 2.4 units. The major complaint of 72 now is being shot down by someone on the same frequency so let's apply frequency hopping to that.

If anyone does it just remember, it was my idea.
Old 01-13-2011, 10:13 AM
  #194  
onewasp
Senior Member
 
Join Date: Dec 2002
Location: USA
Posts: 2,035
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?

We'll be more than happy to direct the FCC investigators to your site.
Old 01-13-2011, 11:23 AM
  #195  
Nitro-Tom
Senior Member
 
Nitro-Tom's Avatar
 
Join Date: Jul 2007
Location: South Florida, FL
Posts: 586
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: swede47


Geesh, what are you jumping on me for? All I did was send a link to RCModelreviews.

S
Did NOT mean to seem like I was jumping on you......sorry if that is how the post came across.....

The guy at RC Model review has done some good stuff.....

I just do not consider the "Clones" or 3rd party products mainstream so therefore they do not apply.....

As many flyers as there are at my field, over 2000 registered last year......(I was number 1500+ in January and lost my ID in may and was 1990+ with my second ID) If I do not see one at the field over the course of the year, I do not recognize it......

Again, sorry if I came across hard on you, I was meaning to slam FRsky......

Old 01-13-2011, 11:45 AM
  #196  
Nitro-Tom
Senior Member
 
Nitro-Tom's Avatar
 
Join Date: Jul 2007
Location: South Florida, FL
Posts: 586
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: rcfan450


ORIGINAL: Loopman

Guys,
I have gained alot of fresh knowledge here and I think that for the most part this has or continues to be a hot topic. I do not think we should bash anyone on any forum as everyone's ideas have merit. Thank you all for contributing to this thread. As for my original direction on this I will restate that we bought into 2.4 in general because we wanted that magic bullet that would make us like ''Superman'' when it came to frequency impregnability, however I think that for all the good 2.4 has done we are still seeing some Kryptonite seep in every now and then. The gremlins are still with us! I can say without a doubt that the planes I saw (mentioned in the original post) had every conceivable fail-safe and they still succumbed to the same old problems that haunt us with all of our efforts be it 2.4, 72mhz or even Ham Band. I will remove my use of 2.4 to my park flyers and foamies and I'll continue to take my chances with PCM on my larger planes, JMHO! I say to everyone here; ''To each his own'' and I say that with respect to everyone's personal choices.

Happy Flying!

Loopman
I think I have decided to do the same thing as you Loopman. I'll take my chances with 72 on my big stuff and fly my little stuff on 2.4. I flew for several years on PCM and only had one glitch (it was a battery issue, not PCM). I've had several issues with 2.4 on my big stuff and I believe it mostly deals with rx placement (it's not brownout issues, I have some serious power and the rx has light indicators that tell me if it reboots, it never has). Seems ridiculous to me to guess at placement and take my chances over and over when all I had to do before was plop in a PCM and not worry at all. I don't want to fly nervous anymore. PCM all the way baby!

(PS, I live in the boonies, no one else flies around here so I don't have to worry about inteferance issues).


Just an FYI......you do not have to GUESS about 2.4 and Rx unit placement.......with Spektrum and JR systems they offer a flight log....and I have rigged ALL my planes to use one Flight log unit available for only $25

You just plug power into any channel, then make a male to male plug and connect it to the power/data port on ANY JR/Spektrum Rx unit AR7000 (7CH full range) or above.....connect the other end to a 2nd charge jack on the side of the plane...then when you land (Or crash)[:@] after your flight plug in the fligh log and it gives you all the Rx performance data you could want.....

I have since removed from service my only AR6200 (6CH full range Rx unit) and use only AR7000 and above......I check the flight log after each flight.....and all seem to operate WELL below spec....

I just love the Spektrum bashers out here, flying "Brand X" or whatever that does not have ANY LOGGING whatsoever that I have "SEEN" to work....

I my opinion this gives the pilot tremendous visability into the operation of the system, and others such as Hi-tec (via telemetry) and Weatronics (Top of the line data logging) offer simmilar solutions.....

Not trying to bash Brand -X here.....just saying, if you use the Spektrum 2.4 system, learn how it works and use it......given correct use and setup, I seem to have excellent results....

example.....3 or 4 weeks ago, a pilot lost a plane in this back corner of our field [:'(] felt bad for him, but then the guys start talking about the "Coffin Corner" of our field, and it is close to that radio tower....

So I said "Nonesense" and I hovered and looped in that corner for a full ten minute flight.....and I could tell they were just BEGGING for me to loose it.......however I was totally 100% confident in my setup and RF link, since I have over 100 flights on that plane.....and I made it fine.......

so I think all this "Whopla" about 2.4 is for the most part, setup issues......and I think many folks fly JR / Spektrum with total success.....as lots do with Futaba, Hi-tec, and others....

There are many good systems out there and I think Frequency hopping is definetly a plus.....boils down to personal preference for the most part...

Just my 2 cents....
Old 01-13-2011, 11:52 AM
  #197  
Nitro-Tom
Senior Member
 
Nitro-Tom's Avatar
 
Join Date: Jul 2007
Location: South Florida, FL
Posts: 586
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: swede47

I don't know what Nitro-Tom is smoking, but he needs to back off. All I did was to post a link to RCModelReviews about a GUID interference with a FrSky module and jumps on me. Somehow he's twisted it all around and has me flying a $3,000 model with a FRSky 'clone' RX. I have neither. I use some 72 and some 2.4 DX7.

So Nitro-Tom, you need to chill like FLPilot says.

S

Dude, talk about who needs to chill, I just posted the "I am sorry if my post came across slamming YOU, I was slamming FRsky (Cheap Chineese clone)

And I do not smoke, we have random drug testing where I work
Old 01-13-2011, 12:08 PM
  #198  
pilotpete2
 
pilotpete2's Avatar
 
Join Date: Oct 2002
Location: Lyndonville, VT
Posts: 3,305
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?

OK, lets just assume that the model is not made of come exotic conductive composite. Just simply mount the two antennae at 90dg to each other. Located them as far back in the model as practical, in the canopy area, or right behind the pilot, in the turtle deck area, and just go fly The potential problem areas can be better identified by just looking at the model and keeping clear of large objects, and as far back as possible from the spiny thingy. Got a scale warbird that has an antenna mast behind the canopy? Just run one of the coax antennae up in the antenna mast
Oh, and of course do a thorough range check and have fun[8D]
Pete
Old 01-13-2011, 12:09 PM
  #199  
Nitro-Tom
Senior Member
 
Nitro-Tom's Avatar
 
Join Date: Jul 2007
Location: South Florida, FL
Posts: 586
Likes: 0
Received 0 Likes on 0 Posts
Default RE: 2.4 - Why Are They Failing?


ORIGINAL: jquid


ORIGINAL: MinnFlyer


Now, can we get back on topic, or are we done with this conversation?
Not sure.... I think we have concluded that multiple redundant systems on board batteries and Rx included are not a cause for (2) Aircraft at the same site having radio problems.
We have pretty much beat to death the current rates, and I do not think we are zapping it all from multiple batttery packs. Or are we?
Here is a thought, since we are talking about large aircraft, I am assuming that they are running multiple servos ganged together?
Any tests Zor on such a set up? I think it is Airwild that sells those servo trays, and arms.

Zor showed approx 500ma of current draw, but that was (1) lonely servo. How about ganging (3) together and testing the current draw? Are those in a harness or individually put into a seperate RX? Not sure, I do not fly the big stuff. Input guys?

So could we have 3X the current draw from a rudder? Now add elevator with multiple servos, and ailerons, etc?

We have also pretty much elimintaed any frequency close to the transmitter, such as another transmitter. So maybe it is a current spike of having 6-8 digital serovs move together could cause such an issue?

Thoughts appreciated.

Thoughts?

I agree totally.......I posted the specs showing a Hi-tec MICRO servo used in my .60 sized PA Extra MX.......and it's stall current at 6V was just over 2.1 AMPS[:@]

Imagine what 4 or 6 JR 8611's or 8711's could pull......and I know for a fact that the Fromco Dual Regulated 2 cell Lion setup I use in my 30% Yak delivers only 20 amps to the Rx....and this is a typical setup.....the JR / Spektrum Regulators I see alot of are only 10 Amps....with 16 Amps peak....so there is a MAX to the Rx unit of 20A with a peak of 32AMPS (Which is ALOT at 6V)

So we are giving these setups the best input power we can without an on board nuclear reactor but we can still get into trouble if we do not have enough regulated power input, and enough power "Distributed" to the servos.....

Lot's of opertunity for voltage drop here, which is the enemy......



Old 01-13-2011, 01:13 PM
  #200  
rmh
Senior Member
 
rmh's Avatar
 
Join Date: Dec 2001
Location: , UT
Posts: 12,630
Likes: 0
Received 3 Likes on 3 Posts
Default RE: 2.4 - Why Are They Failing?

Actually you never see those kinds of loads -in rx to servo connections - The wires just won't carry it nor will the connectors.
But as you noted voltage drop IS the problem and the wiring (especially the connections)acts as resistors.
In electric powered models we see 40 PLUS amp loads all the time and so use seperate batteries or a switching type reg.
The JR/Spektrum switchles connector setup on th e big rx is great because th buss on th e rx is fed by BIG wires direct from the battery which will carry 40 amps

The servos can pull as hard as they want and even in peaks caused by fast reversing never bother the power supply to the rx buss
Typically I read one aprox volt drop using A123 2300 ma cells in parallel on these setups never as much as 2 volts drop
Other batts and wiring - can cost one the farm . So feed the rx with batteries with super duper output capabilities
the crap (and thats what most were ) we all used on old 27/72 sets just won't cut it
the crummy LiIons and regs and old NIMH cells which had no staying power - should be avoided.

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.