fytrjok

My Feedback: (2)

Valleyk,

Dude! Yes, this certainly can be a touchy subject. As you are aware and as has been said, hundreds of flights are logged almost on a daily basis at Chatfield. Everything from micro-electric to twin turbine. I also have seen multiple aircraft go down on any given day. You know who I am. You know the level of aircraft I fly. If I even had a mustard seed's amount of doubt as to whether it was safe to fly at Chatfield, you can bet that I'd only be risking $100 foamy Warbirds instead of my children. I fly there every weekend that's flyable, as do my flying buddies. Together, we log multiple flights on each plane we bring all day on the weekends. Most of us fly Futaba 2.4 and to my knowledge, none of us has experienced any radio signal problems. I'm wondering who the "6" planes belonged to and were the pilots of those planes convinced that they lost their planes due to external interference. I also don't recall seeing you fly anything recently. My friend, from knowing you, I am getting the impression that you may just be being a little paranoid. I know you cherish your planes as I do (notice I called them my children), and want to be sure you've eliminated everything you have influence over to protect their lives! It's your call as to whether you register and fly at Warbirds Over Denver...we'd love to see your giant DR I fly! But please, be really careful and sure of your facts before you start spreading ugly, unfounded rumors about the RF integrity at and around Chatfield, especially as it relates to the Warbird event we're working hard to promote! By the way, I don't recall ANYONE who flew at last years event complaining about RF issues, although we did award the infamous "Smoking Hole" award for the most spectacular crash! There is one sure way to prevent your pride and joy from being reduced to splinters...don't fly it...ever! If you have a concern, I invite you to bring it up at one of our Club meetings. We do have the "juice" to investigate just about anything that involves RC at Chatfield. See you at the field...or maybe not, but rest assured, I'll be there...with my most prized Warbirds.

Doug

A10FLYR

My Feedback: (1)

I'm going to continue flying my 2.4 at Chatfield as I have for years. There are far to many successful flights for me to be worried. While I have seen some crashes due to the orange RX, (at least that's what we think), I think there are other reasons for them. Remember, we had people saying the same thing with 72 mhz back in the day! Ace has done a lot of research so he has credibility but I'm going to continue to test Mr. Murphy!

valleyk

I'm sorry. I did not intend to upset anyone. I have been known to be a little paranoid at times. I still plan to attend the warbirds show.

fytrjok

My Feedback: (2)

No biggie! We look forward to seeing you at the event! Hope you bring the DR I, I heard it flies beautifully.

aquaskiman

My Feedback: (46)

Think for a minuet what you did here. One month before Jeffco is going to host a major event you start a rumor that there is a interference problem at Chatfield. I fly there a lot and know most of the warbird and jet flyers that fly at Chatfield. I know of no radio related crashes. Yes a few foamy’s that have $5.00 receivers. Are you even a Jeffco member, or are you one of the many that use the field and do not support it. George

Dick T.

My Feedback: (243)

From an outsider looking in I believe valleyk expressed an opinion based on his experiences at the field be they $5.00 receivers or top end equipment. He did not start a rumor but merely shared his concerns.

Some posters have said they have not flown there in some time, others talked with members who knew nothing of it. None of that means the concern, or a problem, does not exist.

There is a bigger world out there than what swirls around any individual's head. Many things occur beyond one's personal horizon.

Good luck with the warbird fly in.

DadsToysBG

My Feedback: (35)

A whole lot of nothing for two pages. Dennis

dirtybird

My Feedback: (5)

I would like to know what 2.4 manual warns about cell phone use. I checked and I could not find any carrier in the USA on 2.4

http://allworldcellphones.com/gsm-frequencies-list.htm

BuschBarber

My Feedback: (2)

I use a cell phone and a Bluetooth headset every day, wherever I fly. Never an issue.

Truckracer

My Feedback: (19)

It was once common to have 2.4 GHz. microwave links between cell towers but those days are pretty much long gone. Any links today would be licensed except in maybe a few really remote sites. None of the licensed frequencies are anywhere near 2.4.

Last year, one of the local fields experienced repeatable crashes and of course they blamed a nearby communications tower. Still employed at that time (now retired) I took the spectrum analyzer to the area and found zero 2.4 emissions from the tower. On the other hand, a large seed corn company had fields in the area and were using equipment that pretty much blanketed the whole unlicensed 2.4 spectrum. They use the equipment during planting and field layout during the spring and this was wiping out some brands of radios. A few weeks later, the problem was gone as they finished their work. I have not heard whether they had a similar problem this year.

Interference is possible but rather than starting rumors, I would find someone to do some testing and either confirm a source of interference or put the rumor to rest.

YAT-28E

Great, I start flying and my buddies wife calls him on his cell phone to quit playing and my plane goes in.....

what next, cats and dogs living together, mass hysteria!!!!!!

Lets fly.....it be ok

warbird72

My Feedback: (79)

You guys aren't going to crash!! If you worry about it you will jinx your selves. Just fly. Have fun.. Just sayen.

warbird72

My Feedback: (79)

I'm still learning to trust 2.4. But I'm here to say that it's gaining it. I have large gassers on 2.4 I also am starting to switch over my glow models. This past week I was flying on 72 meg got a very slight hit. Nothing major bit freaky. But the plane is old. Still I'm pristine condition my scratch built hots. But I checked my batteries and went right back up! To the same spot asking for a problem. It wasn't there.

DadsToysBG

My Feedback: (35)

Well finally with all this talk about 2.4 Truck finally has something that could be proved. He's the only one i know that has ever found something and the problem hasn't returned.

JIMF14D

Were you watching/listening to him on the phone when your plane went in......?................

Dick T.

My Feedback: (243)

And what Truckracer also proved is that 2.4 can experience interference. Usually most crashes are due to inadequate RC installation and maintenance, something you see regularly at any flying site. This was even true in the 72mhz heyday when most interference issues were caused by another flyer shooting you down.

But there is still the mysterious shootdown no matter the frequency band. It happens and 2.4 is not immune.

DadsToysBG

My Feedback: (35)

I agree, but the problem Truck found is still the first provable problem I have seen. Just like the OP. most are "I heard" comments never "me". And I did say most not all

dirtybird

My Feedback: (5)

Yes its probably the only actual 2.4 interference case. Spread spectrum was developed to reject jammers which is nothing more than man made interference. It proves that if you wipe out the entire band you can interfere with it.
I sure would like to know what that AG company was using to wipe out the band. It had to develop a lot of power.

Truckracer

My Feedback: (19)

dirtybird, I have wanted to investigate the equipment the ag company was using but have never got around to doing it. I had heard of the same problem completely wiping out any WiFi or commercial spread spectrum operation in other areas so suspected this was the problem when it was reported to me .... but everyone wants to blame the "Cell towers". As a point of reference, when there was a gap between frequencies on the spectrum analyzer ..... and the gaps were rare, the noise floor was about a -60 or even a bit higher (meaning stronger for those who don't understand signal levels). The signals had the appearance of some kind of WiFi related signal, actually several of them all working at the same time, adjacent to each other and with a lot of thruput. WiFi signals are bursty by nature but these signals were fairly well saturated. Much easier to describe if you could see the scope.

While I saw this happen, I certainly don't worry about interference on 2.4 when I'm flying. Most flying fields are somewhat remote by nature and distance from an offending signal is our best defense from interference if it would exist. But if the offender is on the ground right under your flight path, the results might not be pretty.

Overall, the RF link on our systems is very robust and thats all most of us really need to know about them. Yes, they can be interfered with but its not likely under normal conditions. As others have said, a loose plug cap or a sloppy installation will crash far more planes than any interference source.

warbird72

My Feedback: (79)

I read something long ago about ag company's using some sort of EMP? But if that was the case I wouldn't think you could drive your car away! I have no idea! Seriously.

DadsToysBG

My Feedback: (35)

I think that the company blanking out 2.4 would be braking the law and the FCC would be interested. that may be why you've never seen it again.

Truckracer

My Feedback: (19)

Actually after spending most of my working life in the communications industry and working with microwave extensively, I'm pretty sure the equipment in use was in fact quite legal. In the unlicensed 2.4 band, there are regulations on effective radiated power (ERP) but few if any regulations on how much, or even if all of that spectrum can be occupied by one user. Further regulations clearly state that a user can't willingly cause interference to another but that a user has to accept (and usually work around) interference he may encounter. As a result, a sort of gentleman's agreement exists in the industry. If I wanted to install a new, 2.4 GHz. unlicensed microwave link in an area I would do spectrum analysis in the area, look for existing antennas, etc. As a result, I would try to use a frequency range that didn't interfere with another user. In most cases today with so many users on 2.4, I would probably recommend a completely different frequency range or perhaps a licensed system.

How could this relate to the RC world? Well we are occasional and portable users of the spectrum. Likewise the ag company would be the same. Clearly they can do more damage to us than we could to them but they may set up their equipment when no RC activity is going on. Further they may have no knowledge we are on the same frequencies. It would be up to the RC club to visit with the ag company, determine the few days out of the year when their equipment would be in use and perhaps just not fly on those days. That would be the easiest resolution.

They are using the 2.4 frequencies for the same reasons we are .... cheap, reliable, available without special license, etc. Working in a rural setting, they would very rarely interfere with other users.... unless they would happen to neighbor that very rare RC field. Another mile or so away from the RC field and they would probably be no problem at all.

I repeat so as not be an alarmist .... our 2.4 GHz. equipment is very robust and reliable. In the very rare case that interference would ever be encountered, investigate it and try to come to a resolution with the other user.

Dick T.

My Feedback: (243)

Thanks Truckracer for the concise explanation from someone in the know.

DadsToysBG

My Feedback: (35)

Thank you, this is what these forums really are good for. Facts. As a good TV show said "just the facts ma, nothing but the facts". The JoNall showed one year just how good our new system is when they put up 100 planes on one system. Yes it did show the limitations in that the response was a lot slower but it also showed that 100 of the same plane will fly if you can keep up with yours and not try and fly someone ele's.

dirtybird

My Feedback: (5)

I am curious. You say the noise floor was -60 DBM, I am assuming you mean DBM. What is the bandwidth of your spectrum analyzer? That seems high. The quoted sensitivity of the spread systems is -100 DBM. Assuming a processor gain of 10db, you have lost 30db of sensitivity. That AG machinery must be putting out a lot of energy outside if the spikes you saw.
As I remember the noise floor at 20degrees is 128DBM at the 1 cycle bandwidth. You may need to correct me. Its been 47 years since I worked in that field.