Radio interference any solutions?

| Well I think the responses so far have been pathetic.

But this isn't?

| You have provided a huge amount of detail

I wouldn't call it huge. It's certainly adequate, but not huge. Huge would include the output of a spectrum analyzer, etc.

| on your problem and demonstrated that you are prepared to put in a | lot of time and expense to field a first class model yet you have | been told that nothing else can be done to protect yourself from | idiots.

Nothing legal, using off the shelf components and 100% effective, anyways. But the FMA co-pilot/flight stabilization (mentioned later) comes close.

| Well if you are prepared to work as hard as you have to get a | 1/4 scale into the air, you are entitled to look for and develop the | innovative solution. | | Now my ideas won't all be appealing, many are illegal or way too hard | but perhaps there's something here to brainstorm into best practice. | | _Going out of band_ | 1. Already suggested, the Ham bands.

Not a magic bullet. In some cases, it may be *worse* than the current situation.

| 2. The RC band from another country, yes obviously illegal but at least the | equipment can be had without modification.

Yes, but what if the licensed user of that band interferes with you.

| 3. Purchase a license in another band. Just like a taxi company. You pay | your money and get exclusive use of a carrier in your area. Then pay a | sparky to modify your Rx and Tx circuits.

That's not a bad idea, actually. Not a magic bullet, but not a bad idea. I wonder if an individual can actually purchase a frequency like that.

| 4. How about the latest bleeding edge spread spectrum technology.

Still not a magic bullet. You could get shot down by a microwave oven (if you're using 2.4 ghz.)

| 5. Convert your gear to transmit and receive through a pair of mobile | phones.

Oh yeah, mobile phones are 100% reliable.

| 6. Convert your gear to work over WiFi, Bluetooth etc. Put a compact | computer in the air and get a down-link for free.

WiFi range is 300 feet outside. Bluetooth range roughly the same for Class 1.

Not very far ...

| 7. Get some crystals cut to a frequency between two channels, every time | you fly reserve two channels, with a little luck the idiot will be outside | discriminator range of your receiver.

Illegal, and there's pagers in-between our frequencies on the 72 mhz band. So you can now be interfered with by two channels instead of just one, and you may get a 700 watt pager transmission interfering with you *directly* instead of just being on a channel close to yours. Bad bad bad idea.

| _Power Wars_ | 8. Fit a linear amplifier to your Tx. It doesn't need to be as rude as | those 100W jobs that Hams and CBers favour, heck, just a couple of watts | more than the standard RC Tx.

Illegal, and you may cause problems for your fellow pilots. That, and even 100 W only gives you 10x the range -- if the offender is 1/10th as close to your plane as you are, the signal seen by the plane from the two transmitters will be the same.

| 9. Same concept, hang a higher power Tx from your belt connected to | the buddy cable from your hand-held Tx. Just key it on the odd occasion | that you need to blow away the idiot. May need to shutdown the hand-held | Tx without stopping its encoder in order to avoid cross modulation.

Still illegal, and the same problems as before.

| _Panic Detector_ | 10. Obtain a second Tx module and another Rx. Operate the Tx on your belt | or back pack, as above feed it from the buddy port. The aircraft will need | some smart electronics to change over to the secondary Rx - a circuit to | monitor the pulse width from an unused channel, if interference causes that | pulse to drop out then it would change to the other Rx.

The complexity of this setup is more likely to crash your plane than to save it. Especially when you're the only one on your frequency.

| 11. The same monitor circuit as above (forget the second transmitter) | interface the panic detector to co-pilot, a gyro or similar.

Somethng like this --

You can buy this stuff today.

| 12. This one should be good for a few laughs. A receiver somewhere in your | field kit on the flight line. Same monitor circuit as above. This time | when the signal is compromised the clever electronics activates:

| 12a. Automotive air horn, the louder the better, or

Great way to startle other pilots into crashing their planes.

| 12b. An amp, speaker, recorded message: | "GET OUT OF CHANNEL 99 (YOU JERK)"

Better. Actually, the idea isn't too bad -- to let you know when somebody is interfering with you, the moment it starts.

Somebody could make a scanner that scans all the R/C channels, and starts squawking when a signal being received does not match a known AM, FM or PCM signal (like if two people were transmitting on the same channel.) That would be *way* slick. Even slicker -- tie it into the frequency board, and complain if somebody uses a channel while the pin is still in. Overkill for your typical sunday (and not something you can safely leave at the field), but might be useful in contests and the like.

| 13. The fail safe PCM business but in some way interfaced to co-pilot, a | gyro or similar to overcome the objections in your original posting.

One of his objections was `not being accepted by the mainstream of flyers yet' -- that knocks out most of your ideas. Especially the ones that are rude and illegal. :)

Yes, but entertaining as all heck figuring out which one of these is going to get the 'actor' locked up!

Thanks, for brainstorming. It is thought provoking; and not a defeatist attitude I am always fighting within and in replies. Although, when a thought is wrong it needs to be recognized, discussed, but appreciated and built on to realize all the value or lack there of.

Every great invention starts with "what-ifs'" right or wrong and they should cross all bounds. As long, as a Looney bird is not in proximity that will jump to their deaths a mere suggestion. These what-ifs' often will enlighten a discovery or combination that will work. Even if the rules and law administrators need to be shown the solution, costs, and proof for permits or changes in the rules and laws.

One good solution approach is your suggestion of the second channel faulting idea. Worst case; limiting to existing 50 channels and taking the worst case that occurs Greetings warlockg,

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| One good solution approach is your suggestion of the second channel | faulting idea.

The more I think about it, the more I like this idea of mine that I posted there --

Somebody could make a scanner that scans all the R/C channels, and starts squawking when a signal being received does not match a known AM, FM or PCM signal (like if two people were transmitting on the same channel.) That would be *way* slick. Even slicker -- tie it into the frequency board, and complain if somebody uses a channel while the pin is still in. Overkill for your typical sunday (and not something you can safely leave at the field), but might be useful in contests and the like.

This could be made now with existing equipment. Hopefully by expanding on the idea, somebody with the capability to actually build it will do so and sell it (but it's my idea, now published and archived via google, so no patenting it! You're welcome to use it and build said units without paying me royalties, but I'll certainly accept a sample unit or two! :) !)

Basically it would have a pretty normal scanner (like the type you listen to the police with) front-end, that would continuously scan through all the 72 mhz channels (I guess you could add in the 27, 50,

53 and 75 mhz bands if you wanted -- certainly, scanners don't have a hard time with multiple bands.)

Every time it finds a signal over a certain strength, it tries to run it through one of it's decoder circuits. It would have decoders for AM, FM and at least the major PCM types. If the signal is decoded successfully by one of the decoders, no problem -- obviously all is well. If it fails, watch it for another second or two and see if you can make sense of it, and if it still fails, start beeping, displaying the channel in question. Allowing somebody to hear the signal might be useful as well.

If two transmitters are transmitting on one channel, or there's strong interference going on, the signal would be garbled, and so the decoding would fail, setting off the alarm within a few seconds. The only problem I see here is the FM capture effect, where an FM receiver tends to pick the strongest of two signals, which might make things work. But maybe there's a way around that too (I'm not much of a RF engineer.)

The device would have a display that would show all the channels being scanned and if they're being used, and what kind of signal is detected. Giving the strength of the signal would be nice too.

Since somebody might show up at the field with something unusual that always sets it's alarm off, or a known pager tower interferes with a given channel -- stuff like that, it would be able to lock out (ignore) certain channels. And you could pick the bands that it scans

-- no need to scan the non 72 mhz bands if all you care about is 72 mhz.

As an optional attachment, a frequency board could be sold with it, or some sort of interface to a frequency board could be made and attached to it. This way, it would know which channels had a pin out, and if somebody started transmitting on a channel where the pin was still in, it would squwack -- which would immediately catch people who forget to take their pin, or people flying park fliers in the park next door, etc. Without this attachment, an operator could always manually just tell it the channels in use and then it would work the same way.

As a `cool but probably impractical' feature, it could come with a directional (probably yagi) antenna for each supported band, and instructions on how to use it to determine the direction that a given signal is coming from. Unfortunately, an appropriate antenna for even the 72 mhz band would be pretty big, and it would be almost 3x as big for the 27 mhz band ... probably not very practical.

Since it knows when a channel is in use, it could keep track of that, allowing people to see which channels are the most popular over time, and which channels have the most problems.

Especially when coupled with the frequency board attachment (or somebody manually telling it about the frequencies that should be in use), it would take care of most of the frequency control problems, warning immediately about people turning on without a pin, turning two radios on at the same time or strong interference on a given channel from an unknown source. It would also warn about radios that were so far out of tune that they interfered with adjacent channels, or wide band radios that were brought in and turned on.

It wouldn't completely solve the problems of frequency control, but it would let you know when there was a problem so you could either find and educate the people involved, or at least assign blame where it belongs.

Now I just need somebody to see this post, like my idea and actually build it. :)

Wasen't there something in MA back in the '80's that accomplished this?

You are correct this public domain opens ideas from being easily made exclusive. Automation of the spectrum(s) monitoring though probably not new could be a good idea; if the effort is scaled with a build-able marketable product in mind. Governments have active frequency monitoring and alarming with computers saving on required heads and improving precision. However, this system does not help us in our daily flying; RC must be low to no priority?

Minds on the same paths develop mirroring and embellishing concepts, but drive each other faster farther down different paths. Who put the correct pieces together first is always debated unless you have a locked door. Nevertheless, the laws have shown in practice, being right is only part of the formula and have varying influence. Often in business law, the party with the most money, wrong or right can perpetuate costs driving the individual out of the judgment process. Alternatively, backdoor deals for profits needs are often well funded and coined as favors or settlements also circumventing the right and wrong weighing of an issue. And throw in the variability of the luck or purchasing of the lawyers skill on a side and you have another variable that MAY affect the final results.

Thinking of the ideas is 1-50% of the effort. After many years of R&D engineering, I accept that making a working model is another 10-70%. Manufacturing development can be 1% - 95%. In addition, without the additional 1%-95% focused marketing efforts, it will all fade away, or perpetuate. Many great patents are expired, sitting, re-invented, and often

Development of a usable product is difficult; especially with public use and abuse involved in using the product. No matter how beneficial (airbags data proven mega lifesaver), some opportunist will imply liability for your engineering lack of foresight for any unforeseen issues. In addition, this liability increases exponentially with the depth of your pockets. If someone does develop it, that person is taking all the risks, investments, marketing, and solving the real problems and inventions yet to come. Once a working model is developed, you are 50% done. Only continuous development, business plan, legal liabilities, and manufacturing issues remain.