fastplane

As a one year beginner to RC planes I am disappointed that we are open to be shot down by someone just outside the field with a small flyer and same channel. What work is being done by manufactures to be sure that my plane receives ONLY signals from my transmitter? It's not just a possible loss of a plane but injury to people also that concerns me. Thanks.

BillS

The question is interesting and important. I hope you get answers. People safety is the most important issue. Many are concerned that $5,000 airplanes are at the whim of a ten year old with a new $50 radio.

Bill

mstroh3961

My Feedback: (4)

There are receivers available from Berg and FMC that lock on you transmitters specific electronic signature, and will disregard signals from another transmitter on the same freq. I have witnessed a test of this with a Berg receiver and two 9C transmitters. The receiver stayed under control when the second transmitter was turned on. The servos would twitch slightly if the second receiver was closer than the primary.

This receiver was installed on a Slo Stick.

Rodney

Cost is the main reason. Given unlimited funds, you can have a receiver that uses encoded info and will continue to properly perform under most conditions. There is nothing that will withstand every kind of interferance or that can not be overwellmed by excessive power within its spectrum. What are you willing to pay?

fastplane

What is your or someone else safety worth? I think safety should be foremost. These are not toys we fly! If your plane hits someone or causes major damage because of radio interferance --- who will be at fault? How can you prove it? How will you feel? All radios today have plenty of functions to meet almost any flying position you might want. We need to stop thinking in only the same way of solving safety. The manufactures need creativity thinking not just more of the same adding functions and bigger screens.

smokingcrater

also, it isn't quite as bad as some would make it seem. I haven't seen a 'toy' rc yet that actually runs on our frequencies. they all seem to be on 27mhz... so then the only thing you have to worry about is other people that should know better.

fastplane

Yes, I agree we should not be concerned with the toys. My statement was to note we don't fly toys and our planes can cause real damage. There are other things to be concerced about. Many small planes are being sold on the same 72 Mhz. These folks may not belong to any club and only want to fly in their yard or park and not aware they may cause interference close by.

BillS

Was the test witnessed under flight circumstances? Or was it simply a proximately test on the ground?

Bill

BillS

Time out. On what basis is the cost comment made? How much do you think higher frequency security might cost?

Fifty-dollar walkie-talkies have 38 privacy channels. That is two for fifty dollars.

Bill

BasinBum

My Feedback: (2)

I hate to break the news to some of you but these are toys. Out of control planes (radio shoot downs) rarely hit anybody and it's not the holy safety issue that Chicken Little would have you believe. It is about money and the major manufacturers would surely develop expensive spread spectrum tecnology if they couldn't sell cheaper ppm and pcm radios. The main driving force that will cause people to buy SS radios when they finally become available will be to not lose their investment and safety will be a secondary consideration. The tone encoded squelch used on $50 a pair walky-talkies would't stop the signal noise you experiance in a shootdown.

BillS

I am in total agreement with your comments about safety. The airplane is inconsequential.

Bill

mstroh3961

My Feedback: (4)

We ran the test on the ground first, then duplicated it under flight conditions. the slo stick was under controle at all times. granted this was a small park flyer.

BillS

I certainly hope you are wrong and that people are considered more important than a damn airplane.

Bill

Flying Geezer

My Feedback: (14)

I agree with your concerns. I would like to see the FCC limit the 72mhz band to organized model clubs, and put the "toys" all on the 27mhz band. There is a substantial difference. It's only a matter of time.

I fly with a club. The runway is 150 yards from the river. Directly across the river is a large park. I think it's only a matter of time until some one shoots one of us down.

The signature signal problem is not expensive, it's cumbersome. A few cents will add the signature to the transmitter and receiver that you buy together. Additional receivers purchased later, would have to be programmed. It' still do able however, and like most problems, they will fix it when they have to.

mr_matt

My Feedback: (10)

My partner and I have been flying a wideband (spread spectrum) system for awhile, it is not that easy to set up as a commercial product. The technology is tough too, but packaging it as a product that could be brought into the market would not be easy. It will likely have patentable technology in it by the time we are done. There is already a car system on the market BTW

As far as this notion of making a narrow band RX more secure, I do think certain things can be done, but there is no substitute for the advanced spread spectrum technology that is out there now....no comparison.

Lynx

The problem with spread spectrum is that it uses non-licensed channels that have even stricter power output limitations than does the 72mhz band. Also you have a billion other devices that use the same frequencies to contend with, and even though spread spectrum helps dealing with interfereance it can not eliminate it, range still suffers in the presence of noise, considering the power output limitations are already pretty high it's a little chancy to use these for RC applications without illegal boosting the power. Car systems are out because cars don't go to nearly the range an aircraft does. While it's probably a solution for some hardcore jet fanatics in remote locations untill they open up a non-licensed band with higher power output I doubt these systems will catch on in the maintstream.

BillS

Lynx,

If Spread spectrum appears to be a problem what do you suggest?

Lets not wait until a 40# runaway model kills a prominent Senator’s child or grandchild because of a park flyer turned his radio on. Government regulation is bad for everyone. Regulation is coming if we do not correct the growing deficiencies related to frequency conflict.

Bill

mr_matt

My Feedback: (10)

Wrong....the ISM band in 2.4 GHz is limited to 1 watt output, greater than the legal output on 72 Mhz. Of course 72 MHz that we use now is unlicensed as well.

Well that is a very hyperbolic comment...if 1 billion people were at the same place, then there might be a problem. But soon, a billion people worldwide could begin to use the ISM band frequencies without interference with each other.

fastplane

It is a fact there is frequency conflict. And the problem will most likely grow. The best is for the hobby to fix the problem before the lawyers and government agencies get involved. We will not like their solution! I don't know if SS or something else is the answer. I do know after many years of experience that all problems can have a reasonable solution if enough people want to. Manufactures need to 'think outside the box' and get moving on a solution.

mr.rc-cam

It is not fair to compare R/C's VHF spectrum with ISM's microwave spectrum. The latter is very lossy.

For example, given equal Rx performance, a 72Mhz R/C Tx with a typical RF power of 200mW, has an effective range that is sixteen times farther than a [/i]1000mW[/i] 2.4GHz ISM transmitter. Related another way, the ISM Tx would need to use about 250 watts (versus 200mW for 72Mhz) to have the same effective range. That is for very clear line of site operation. The comparison range grows even further apart when the environment is not LOS or there are neighboring RF reflective surfaces (cyclone fences, cars, buildings, etc.).

I'm not saying that it will take 250 watts to get a mile range (that can be accomplished at the low power level with properly chosen Rx sensitivity). I am just pointing out that 1 watt of 2.4Ghz RF power is not as impressive as it seems. But, there will be new user/site related RF issues to deal with that do not affect 72Mhz operation.

RC-CAM

BillS

The following address of Jef Raskin’s discusses the above quotes.
http://humane.sourceforge.net/publis...ansmitter.html

It is an interesting and worthwhile read.

Bill

fritzthecat

My Feedback: (4)

To change the current RF freq and encoding schemes:

1- Something significant must happen. a) It must be either something that makes the 72Mhz spectrum unusable for hobby use. Or b) A legal / government action placing restrictions or outlawing the freq for RC use.
A) could be something like BPL, the 72 Mhz being sold to some commercial enterprise or too many 'toy' parkflyers.
B) would be a accident in which an important (read political or entertainment or other sympathetic) entity is maimed or killed resulting in a media / public outcry. Homeland security could consider RC craft as potential terrorist weapons and outlaw or severly hinder their use.

2- When this happens, Futaba/JR and many other RC equipment manufacturers will all of a sudden bring out SS, Ethernet or packet radio systems and sell them at a premium price.

Nothing is going to happen until change is FORCED by circumstances. A part of the problem is the median age of RC pilots hovers around the 60 year mark. And (no flames please) old people are more reluctant to change. I still see many 4ch gold stickered Tx and there are some that refuse to fly that 'newfangled' narrow band equipment. They will not switch to something new until the old stuff is unusable. I estimate this to be happening in the next decade sometime.

Fritz

s3nfo

My Feedback: (14)

No, You can do spread spectrum on any freq. The military does spread spectrum on UHF and we could do spread spectrum on the 72mhz channels we currently have which would not only fix the interference problem (who cares if 1 or 5 channels are getting hit, your only on that channel for a few microseconds) and would also fix the problem with freq control making pin boards obsolete (Nobodies gonna be on the same hop pattern as you are unless you get a couple hundred guys flying at the same field at the same time).

Panzlflyer

My Feedback: (15)

Money, money, money and how to make it with the least effort!!!

BillS

fritzthecat,

Thanks for your well thought out comments regarding the promotion of safe flying by eliminating frequency conflicts.

The AMA appears to be our primary method to promote safe flying, field safety, and smaller field liability. Does anyone know if anything being done by AMA to encourage the manufacturers to avoid the pending inevitable frequency conflict crises?

A thread ‘Obsolete the Pin Box!’ in the AMA forum produced bizarre unexpected results.

Age should be an excuse for wisdom, not stupidity.

Better frequency safety doesn’t have to be an all or nothing change. It is believed a number of transition strategies could be devised allowing the new to be immune to frequency conflicts and the old to continue to operate. Natural selection through crashing would continue to remove older equipment at an ever-increasing rate. Those who wanted to operate risky (maybe they fly to build or simply enjoy the thrill of crashing) could continue into the future with ever increasing risk. Those concerned about safety could fly without fear of being shot down or injuring someone. The high dollar airplanes could be saved from the $200 Junkers.

The major radio Distributors increasing liability exposure due to a failure to insist on safer frequency control will follow.

Bill