RichD

Is there a chart or anything for the most common freq's ppl use? I was told that I do not ever want to get chans 42, 50, or 60 because the wait will be long...haha

Everytime I go to the field, chan 52 pin is always in the box, and thats the one I plan on getting.

Thanks,
RichD

RichLockyer

LOL! It is going to vary from field to field (and year to year).
One freq that is almost always clear is 13!

RichD

ooops, forgot to check the "Notify me via e-mail when someone replies " box as I dont frequent this forum much.

3DFanatic

My Feedback: (5)

I started on 37. Had it for a year with absolutely no one else inthe club on it. Then BOOM 3 others had 37... OK. I go the the LHS, reach into the box of crystals and buy the first one I pull. Ch60. I use that for over 6 months with no one on it and then BOOM at the end of this last year 3 or 4 others are on it. I now fly 41 and know of only one other at my club that flies it and I hardly ever se him so i'm good for a while.

wyflyer

My Feedback: (7)

I have flown on 38 for four years and I have not run into anybody else who had it.

Highflight

My Feedback: (4)

I was flying once and all of a sudden, BOOM. That's it; just BOOM.

Highflight

AMA-69405

My Feedback: (22)

RichD,

I agree with an earlier reply... frequency crowding on particular channels will probably vary greatly from club to club. However, for what it's worth, I have just spent the better part of a year doing a frequency survey for our club. I think I can state one fact unequivocally; something very non-random happens with frequency distribution in a given group of fliers. In our case, I gathered up the channel numbers for about 90 fliers, representing no less than 160 transmitters. ((I'm always amazed when someone gives me 5 or 6 frequencies! Why don't they peddle all those old single-model transmitters for 30 or 40 bucks apiece on eBay, and use the proceeds to buy one modern 6 or 8 model computer Tx?))

Anyway, here are the distribution numbers:

Channels with 1 user: 11, 30, 53, 55, 59, 60
Channels with 2 users: 12, 13, 14, 17, 19, 21, 24, 27, 45, 46, 47
Channels with 3 users: 26, 28, 35, 37, 41, 43, 44, 49, 51, 56
Channels with 4 users: 15, 16, 18, 23, 25, 29, 31, 32, 33, 34, 36, 57, 58
Channels with 5 users: 22, 38, 39, 40, 48, 52, 54
Channels with 6 users: 50
Channels with 7 users: 42

Like I said... obviously, something non-random is happening here, but I don't know who or what to blame. In a perfect world of 160 transmitters and 50 channels, the vast majority of channels would only have 3 users, and a handful with 4. But we've got channels with 5, 6, and even 7 users, and therefore, several with only 1 user; in fact, prior to this campaign, there were 2 or 3 channels with NO users. The only distribution anomaly that I can explain is the low number of users on channels 11 through 14... JR does not sell radios on those channels, and a lot of the fliers in our club use JR equipment. (Incidentally, you won't see channel 20 in the data above... we do not allow that channel at our field due to possible interference from a nearby TV Channel 4 broadcast.)

In any case, in order to start leveling out the usage, I keep the 4 local hobby shops supplied with the latest survey results and post a copy of the same data on the frequency board at the field. We've had some success, with fliers who've purchased new radios letting me know they used the data to avoid the crowded channels. In another 30 or 40 years, we should have this problem whipped!

Good luck... I'll be amazed if your club has ever done a survey like the one above. It IS a lot of work, believe me.

Gary L.

Montague

Our club collected the info then published the graph of most used channels. If you do that once a year with the club renewal, it evens out in a hurry as guys move to the open frequencies.

Of course, you can always do what I did, move to a TX like the Polk or Hitec or some of the other settable ones, and use the Polk (are there others?) crystal-less receiver.

Gene Chernosky

My Feedback: (182)

Something else to keep in mind...industry and several other users also occupy the 72 mHz band. They typically use 'even' frequencies (ie 72.560 mHz) vs. we use 'odd' frequencies (ie 72.570 mHz). They also are allowed FAR more signal strength than we are allowed so their adjacent frequencies can EASILY 'shadow' over ours if conditions are right. There used to be a free website (they charge for the service now) that would allow you to check your county/state for used frequencies...I'm not sure if they are still around...maybe someone knows a link??? Anyway, my county, Walker, is basically blank...then one South towards Houston, Montgomery county, has a few to worry about...then Harris county, where Houston is, is virtually inundated with 'other' users. So...all of your problems may not be centered on the guy next to you turning on his radio...it may be Bubba down at the 'yard' running his crane that shoots you down!

RichLockyer

It seems that you have some of the making of a typical bell-curve here, except that your peak is at 4... both 4 and 2 are "robbing" from the truly random peak of 3.
Adding channels with 0 users (other than 20) would balance out the two above 5 with two below 2 users.
Only one channel each with 6 and 7 users would be possibly impacted by the deliberate (non random) attempts of those already active to avoid heavily used channels... this could also skew the results to favor 1 and 2 users if those buyers also did a quick informal survey similar to yours by carefully watching the freq board for a few weekends.

A sample size of 160 transmitters is a decent size, but those with 5 or 6 radios will definitely affect the sample since their redundant radios won't be as random as the first.

3DFanatic

My Feedback: (5)

It seems that you have some of the making of a typical bell-curve here, except that your peak is at 4... both 4 and 2 are "robbing" from the truly random peak of 3.
Adding channels with 0 users (other than 20) would balance out the two above 5 with two below 2 users.
Only one channel each with 6 and 7 users would be possibly impacted by the deliberate (non random) attempts of those already active to avoid heavily used channels... this could also skew the results to favor 1 and 2 users if those buyers also did a quick informal survey similar to yours by carefully watching the freq board for a few weekends.

A sample size of 160 transmitters is a decent size, but those with 5 or 6 radios will definitely affect the sample since their redundant radios won't be as random as the first.
[/quote]


WHAT???? [X(]


Just BOOM? ouchies.

JohnW

My Feedback: (6)

Looks like a bell curve to me too. 160 radios across 50 freqs statistically really isn't enough to see the curve mature, but it is obvious by inspection that it is there. My vote is for random population. Oh, by the way, I just heard that CH44 has been outlawed and no one can buy it any more. If you are on ch44, you need to throw away your xtals ... he he he.

RichLockyer

LOL!
Following the law of probability, purely random placements with a common starting point will always form a curve that looks like a bell.
In this case, the common starting point would be "3.2 users" since that is the sample size divided by the number of available "random chances", or 50 channels.

If you throw pennies into a dry well day after day, the stack at the bottom will form the shape of a bell, and not (only) because pennies are sliding off of the top of the heap... they actually land that way. If you coated each penny with CA before dropping it in, it would form the same shape. Many science museums will have a probability display which is a large, thin box full of evenly spaced pegs and a row of tubes on the bottom. A bunch of balls are dropped from the top, and as each ball hits each peg, it has a 50% chance of going right or left. If the law of probability dictated that every other time it would go left, then right, then all of the balls would be in a stack in the middle, but it's not... the odds are the same 50% each time, so you end up with a few that ALWAYS went left and a few that always went right.
It is so predictable that they have a bell shaped curve drawn on the sides of the box, and the stacks of balls always match the curve.
You really have to see it... my description isn't very good. This is close: http://library.thinkquest.org/C00608...ive.shtml#bell

This is also how Vegas takes your money

Similarly, in a sample of 16,000 pilots, the highest number of channels would be in use by 320 people, with a perfectly bell-shaped curve graphing down to 0 channels with 0 users and 0 channels with 16,000 users (and yes, you would reach 0 channels long before you got to 0 or 16,000).

AMA-69405

My Feedback: (22)

Actually, before I started advertising the unused channels, there were a couple of "zero user" freqs; they have now become occupied and in fact, the last free channel (59 as I recall) came into use just a few weeks ago. The as-discovered distribution was a nearly perfect bell curve, immediately recognizable as such. The real question (and the non-randomness I referred to) would be then... what drove 6 people to buy a radio on channel 50, while absolutely no one had purchased one on channel 59? In a situation where you have some choice, why would the guy that bought the 6th ch 50 radio, not buy one on 59? He had to have noticed that 50 was often in use. Maybe the LHS owners had some affect; maybe they have "favorite" and "poison" channels, for reasons that may or may not be valid. Maybe the radio manufacturers are actually building more radios on certain channels? Highly unlikely... that would be terribly easy to control at the manufacturing end of the chain. Maybe old wive's tales about certain channels being no good, regardless of the true situation in our club's location? (To my knowledge, no spectrum analyzers have ever been put to use there.)

I dunno... but at least we now have a handle on the distribution, meaning we can start to do something about it.

Gary L.

RichLockyer

The beginner is nearly always clueless, and will get whatever the LHS worker grabs off of the shelf.
The active pilot is generally NEARLY clueless, only knowing that he doesn't want one on any channel that he already owns.

Perhaps the guy who bought the 6th radio on 50 had never actually seen 50 in use at the field? That's happened to me... buy a radio that I think is on a clear channel and the next week there's 4 people on it. We simply can't remember the status of all 50 channels without a written survey like yours, but we CAN remember which of our 5 planes we end of leaving in the garage because there's never a spot open.

dclittle

My Feedback: (2)

I'm not sure the bell curve for frequency selection is entirely due to the laws of probabilty. Could it be that the radio manufacturers produce & ship more radios with certain frequencies? After all, if JR/Futaba/Airtronics made approximately the same quantity of radios in each frequency then the distribution in the field should mimic this production. It is more likely that the manufacturers produce more radios in the middle frequencies because thats what consumers request. If you get a radio with a module then you can always change.

JohnW

My Feedback: (6)

People are funny and I suppose there could be some freqs that aren't selected as often, i.e. the ends 11 and 60 and possibly 13. However, I cannot detect any significant shift towards center freqs in the data provided by AMA-69405. If center freqs were more popular, they should be shifted to the high side of the curve. It still looks like random distribution to me.

3DFanatic

My Feedback: (5)

That's weird... How can something purely random always have a set outcome? AAAAAAH [sm=drowning.gif]

BaronSchwab

I've got two channels 32 and 46. 32 has nobody else. 46 has 2 other flyers.

JohnW

My Feedback: (6)

3D Fanatic: That is the nature of statistical distribution. I've had enogh statistics and high level physics, i.e. quantum, that I guess I just take it for granted. But I can see how it may be confusing that there is order to random events. Impossible to predict individual events, but statistically possible to predict the likelihood of individual events. Want some interesting reading, pick up a beginners book on quantum mechanics. You'll get a lifetime supply of "out of chaos comes order" examples to ponder.

strato911

Interesting topic... Perhaps you can explain why lottery numbers drawn in a similarly random method DON'T produce a bell curve.

Here's the historical number frequency charts of our local national lotteries:
[link=http://www.lotterycanada.com/lottery/?job=frequency_chart&lottery_name=na_lotto_649&order=0&years=0]Lotto 6/49 since June 12, 1982[/link]

[link=http://www.lotterycanada.com/lottery/?job=frequency_chart&lottery_name=na_super_7&order=0&years=0]Super 7 since June 10, 1994[/link]

3DFanatic

My Feedback: (5)

That's equally weird. I love reading about quantum stuff and am a big fan of Stephen Hawking's writings but have never heard of that [X(] Howabout going down to the level of strings and looking for patterns?

AMA-69405

My Feedback: (22)

Agreed... In an earlier post, I had (wishfully) ruled out the possibility that the manufacturers could be a part of the problem. WRONG.

I asked the JR and Futaba reps the same direct question on the subject; i.e. how are channel production numbers allotted at the manufacturing end of the chain. The answers were essentially the same; it's market driven. In the case of JR, they actually said so. Futaba refused to answer, claiming it was proprietary information. (That means of course, they're letting the market drive the numbers as well; if either firm were simply allotting 2% of the production to each 72 MHz channel, I'm sure they would have been proud to say so.) Also, neither manufacturer would provide any data on the percentages produced last year. Proprietary, of course. [X(]

Here are the threads involved:

http://www.rcuniverse.com/forum/72_M...1415095/tm.htm
http://www.rcuniverse.com/forum/72_M...1415105/tm.htm

So... The distribution is not random, and the contributing factors start at the top and run all the way down to the (typically uninformed) individual consumer. If you're in a club large enough to run into frequency usage problems, you WILL have problems; and they will most likely continue to get worse... unless the club itself does something about it.

Gary L.

Geistware

My Feedback: (16)

I fly 38 as well and at my filed, one other person flies it. We take turns and it works out good for the both of us.

JohnW

My Feedback: (6)

Strato: Your lottery chart is not showing distribution based on frequency. The balls are ordered by thier face value in your chart. Rearrange the chart starting with least pulled to most pulled number and you will have 1/2 of a bell curve.

3D: String Theory? Ten Dimensions, Six of which are infinately small, but circular? That makes my head hurt. Beside, string theory is really more of a control line forum topic.