Club Bans 35 MHz

[Phil May]

Maybe I did not make it clear.

 

The turbine incident is not the only one that has been blamed on 35MHz problems and the ban was announced before the loss of that model.

I just feel that, as others have mentioned, 35 can not be blamed for every thing that go's wrong whilst flying a model.

 

Ok, there are those at my club who will argue this point and those with more knowledge of causes of interference, but a rather stiff rule change in my opinion.

 

I think this topic could go on forever and it is up to club members who disagree to decide if they wish to rejoin or argue this decision.

As over 50% of our members were at the AGM last week and all re-joined , I think there will be little or no objection.

 

Phil

[Olly P]

Hmm...if the Chairman announced the ban, and was the one flying a presumably expensive turbine, was aware of 35meg interference issues and so on before flying (must have been why else ban it?).....

 

Did he take "all reasonable precautions" if he knew there was an issue, or did he fly when he knew there was a serious potential risk in using 35Meg?

 

just looking at it from a slightly different POV....

[Martin Harris - Moderator]

Interesting point Olly.

[Erfolg]

It would seem that 99% of posters on this thread do not support any form of ban on 35. For most there is no rational argument with respect to the validity of any ban.

 

Some of us have concerns with respect as to how a club rule change is made and by whom.

 

I have a niggling concern with this type of ban which appears to be based on a prejudice. Why not ban Spektrum, we all have read of issues. Or Futaba 2.4 (my own make) as it is possible to have the TX set to the wrong model (Rx). Or any number off other makes on the grounds of spurious, sloppy thinking, often on the grounds of "safety".

 

Over the years I have seen, and I guess many more contributors will have seen experienced flyers crash models, in apparently mysterious circumstances. Landing seems quite common, with heavily loaded models, where the model has been slowed down. Another is pulling a sharp turn with a similarly loaded model at speed. The one thing that does seem common, it is never the modeller. No one would dare suggest that this demi-God of flying could be culpable. I have also manage to stall my 335 at speed (a light weight) by pulling too tight turn.

 

I also agree with PB, batteries and current draw can often be a issue. I will confess, that one of my recent crashes was due to my Nicad feeding the Rx which was effectively empty. This was only revealed by one of those field checkers. Lipo was fine though. I had previously had shouted that I had lost the model, it is not me. A simple check showed who the culprit in this instance was.

 

There is nothing wrong with 35, as we all keep saying

 

 

[Olly P]

Posted by Martin Harris on 14/12/2011 11:39:34:
Interesting point Olly.

Thanks Martin. Just thought I'd point that out....

 

Regards RF transmission and Digital v. Analog signal loss, I could probably write a small book on the subject but with the o/p we see from Tx's and ranges we normally fly at the effects of DP transmission (or ground wave) propogation limitations are fairly limited.

 

Indeed, in some respects 35 Meg is actually a better frequency for this......

 

 

Olly (Strategic Communicator)

[Lee Smalley]

you can whinge about 35 meg vs 2.4 gig all you like, the weakest link (and virtually allways the cause of a crash) is the human element, simple ....end of argument!

the ban is stupid and will solve nothing

[Olly P]

Posted by Lee Smalley on 14/12/2011 15:03:11:

you can whinge about 35 meg vs 2.4 gig all you like, the weakest link (and virtually allways the cause of a crash) is the human element, simple ....end of argument!

the ban is stupid and will solve nothing

Hi Lee,

 

I wasn't whinging in any way, simply saying that to anyone with sufficient knowledge of analogue Vs Digital signal transmission and frequency reflection/refraction analysis the whole discussion is fairly useless at the ranges which we use anyway.

 

I agree with the weak link being the organic input module (person on the tx). As I say above if the Chairman had made the announcement that 35meg was unsafe due to specific interference at this field (Possible, but unlikely) then 2 questions present themselves:

 

1) why the delay in the ban - if truely a serious risk then it should be implemented with immediate effect?

2) Why when knowing about such a critical issue as a ban on 35MHz being needed did he continue to fly 35MHz?

 

Olly

[Martin Harris - Moderator]

....and on the assumption that this large jet was over 7kg, arguably in contravention of the ANO!

[andy watson]

Just because the operator is the most likely cause of accidents is no reason not to take reasonable steps to minimise other areas as well.

 

(I repeat I agree the ban seems an over reaction, but the principle is sound).

[Erfolg]

Andy

 

The principle is not sound.

 

The same reasoning would never allow a full size aircraft to leave the ground, there could not be airports, which required the approach over any hazard, be it housing, cows in a field. Not one person would set foot outside the door, as risk would be incurred.

 

The thought pattern is sloppy. It is the same one that we read about in newspapers, that the present government finds unacceptable.

 

We as individuals find risk difficult to evaluate rationally. There are many instances, where people will happily drive cars, cycle, but have concerns at the risk of flying etc.

[Ultymate]

I see no good reason not to let 35Mhz fade away due to natural wastage,it's still a functional system, but there's better/safer stuff out there.

[andy watson]

Posted by Erfolg on 14/12/2011 22:07:41:

Andy

 

The principle is not sound.

 

The same reasoning would never allow a full size aircraft to leave the ground, there could not be airports, which required the approach over any hazard, be it housing, cows in a field. Not one person would set foot outside the door, as risk would be incurred.

 

The thought pattern is sloppy. It is the same one that we read about in newspapers, that the present government finds unacceptable.

 

We as individuals find risk difficult to evaluate rationally. There are many instances, where people will happily drive cars, cycle, but have concerns at the risk of flying etc.

 

 

 

I'm sorry Erfolg, but you are completely wrong here. What you are describing is a futile attempt to completely remove any risk. What I am talking about is a sensible approach to minimising risk where appropriate.

Edited By andy watson on 14/12/2011 22:20:51

[Erfolg]

Andy

 

Your approach is not a professional approach to risk management, however you try to justify your stance.

 

Please get yourself trained in Risk Management using professional approach Hazop, Hazan studies etc.

 

I am sure that you will then be more concerned of the risks associated with the model and its operator than if the set is 35 or 2.4.

 

As has been suggested, 2,4 as many advantages, yet the greatest improvement is in the area of increased functionality not a step change in inherant safety of the system.

[Andy Gates]

Does this mean said club will ban the use of transmitters that have multiple model memories because there is the chance of selecting the wrong model memory and only allow the Spektrum units?

 

Surely most of us have either done this or been close to flying on the wrong model memory.

 

In my tour of customers sites, we have one which has banned knives.

The reason is that someone might cut themselves.

All cutting devices must have covered blades requiring lots of special tools.

 

Surely a step too far but who knows in these days?

[andy watson]

Posted by Erfolg on 14/12/2011 22:40:33:

Andy

 

Your approach is not a professional approach to risk management, however you try to justify your stance.

 

Please get yourself trained in Risk Management using professional approach Hazop, Hazan studies etc.

 

I am sure that you will then be more concerned of the risks associated with the model and its operator than if the set is 35 or 2.4.

 

As has been suggested, 2,4 as many advantages, yet the greatest improvement is in the area of increased functionality not a step change in inherant safety of the system.

Once again you are completely wrong. I write risk assessments on a daily basis, and unlike many use them to justify doing things by taking sensible precautions, rather than banning them. Perhaps you will at the very least accept you have just made a statement based in ignorance, and I do not feel the need to take training advice from someone who has no idea of my professional competence. I would, however, take issue with any training who described a principle of reduce risk as not being sound- since the obvious outcome of this is no effort to reduce risk in any form. A blatently unsustainable position.

 

I made a single point referencing increased safety of 2.4, and that was that it removed the potential for another person to directly interfere with your model without your knowledge. This potential exists for 35 Meg. I stand by that statement, and no one has attempted to contradict it. The comparison I then made was such that in the event of all other factors being equal this could lead to a conclusion that 2.4 would reduce risk. Again, I stand by that statement, and again no one (including yourself) has seen fit to challenge it.

[Peter Beeney]

Yes, I would also agree the the principle is not sound. In fact, as I said, it is probably dangerous. Until someone posts some documented evidence that there is radio interference on the 35 MHz bandwidth I would consider this to be questionable. If there has been a number of incidents that were suspected of being interference why has no one decided to check? Monitors have always been easily available from the BMFA if necessary, and these days they may be gathering dust to some extent. If this is interference I would be extremely interested in it, the power levels and exact frequencies etc., because, whatever it is, it is not an official transmission. These frequencies are reserved for modellers, so it’s very unlikely that any commercial radio station would be operating here. As far as I’ve ever been able to find out, there are no transmissions in this area at all, other than modellers. In the event, I believe that overall the military still has an overriding say as to what happens to these frequencies.

If this is proven interference on 35 then I guess there would no need to ban it anyway. Anyone left in any club anywhere on 35 where this was happening would be on 2.4 by tomorrow lunch time; and I think not because they might consider it dangerous, simply because they would not want to crash their models!

If this is not interference, but other reasons, pilot error, power failure and all the other things that cause models to crash, then by not recognising this, it is not a sound principle; and perhaps dangerous in the sense that these incidents will still continue to happen.

But I’m sure none of this is ever going to be proven either way. No one there is going to get shot down on 35 at that site because no one will be using it. However, when the first unexplained incidents start happening on 2.4 there will be a search to find a new excuse, which is perhaps a bit of a universal pastime allover at the moment……

This is just my view, but I would forward this if there were ever any similar discussions at our club.

PB

[Ultymate]

I have to agree with Andy here 2.4G is intrinsically safer than 35 Mhz in as much as it removes the risk of shooting or being shot down by dint of a moments negligence in not using frequency control. I'm not technically savvy enough to know of any actual superiorities of analogue over digital or vice versa, but I see no good reason to ban 35Mhz providing frequency control is vigorously monitored on said frequency.

[Former Member]

[This posting has been removed]

[Tony Richardson]

So it would seem no matter what frequency is being used it cannot stop human mistakes stupid or otherwise other than has been pointed out earlier, 2.4 does eliminate shooting down, or being shot down, by a moments inattention from another pilot therefore banning 35mhz would not prevent issues with power/linkage problems, the ban really seems pointless, as I said before natural attrition over the next short while will see 2.4 as the norm there really is no need for a ban. Don't know how it is in the UK but crystals for 72mhz Radios and Rx's are getting harder to obtain so most guys are changing to2.4 when they commission a new model, and gradually discard their old equipment as it wears out or gets re-kitted

[andy watson]

@Peter

I think you have slightly misconstrued "my principle".

 

I simply stated that reducing risk was a sound principle.

 

I certainly did not, and have not, attributed the crash to anything- I wasn't there. I don't know. Even if I was there, I probably wouldn't know. I agree with you 100% that interference (in any description of it) is only 1 of a wide range of possibilities.

 

I think Eric raises some very valid points too, particularly relating the (presumed) age and quality of the readio gear in what is a high end high performance model.

[Olly P]

@ Andy

 

Especially when this is the chairman who had already announced a ban starting jan 1st due to interference!

[Erfolg]

Andy

 

You may consider yourself an expert in risk management, I do not consider myself an expert, although I have run and managed risk analysis projects, producing "Fully Developed Safety Cases", where Risk Assessments are considered "Low Level", which I have both run and appointed others to manage. If we want to start who has had the best credentials in both certificates, seniority etc. so be it. Although it was what we did as young men at the bar, after a few to many.

 

With respect to the safety of 35 and 2.4. We have very little data with respect to data with respect RC models. The nearest we have is the overall number of crashes etc by models. If we consider that the overall safety could be considered to be the number of crashes, what ever the cause. we could very simply argue. that failure could be expressed by

 

y = a + b + x where y = number of crashes, a = airframe failure (comprising servo, rx, battery, airframe failure), b = the pilot, x.= the radio link on 2.4. The term x could be replaced with "z" for 35.

 

At present I see no reduction in the number of crashes of models on 2.4. They still go in, the expression now used, is it just ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, rather than "interference"

 

Given that the total number or frequency of crashes appears to be unchanged. Certainly no significant reduction, particularly with respect to 2.4, I would argue that x = y. This suggests that 35 is not the significant culprit to the phenomena of crashed models.

 

[andy watson]

Erfolg,

 

You seem to be completely missing my argument, or rather reinterpreting it in a manner befitting a Dail Mail journo dealing with a European Union directive.

 

I said reducing the risk of an accident is a good thing. If you do not agree with this simple, uncomplicated statement, then I really fail to understand you.

 

I should also make clear that I have not made any reference to your experience/qualifications in any field. I do not know you- so how could I? Unfortunately you have not been so prudent about my experience- and hence have spoken from a position of ignorance. As it happens I pretty ,much agree with your risk analysis.

 

If you read my original post I said I had an understanding of how this decision may have come about. To put it into the context of your assessment above:

 

1) I agree we have very little hard data- therefore unreliable anecdotal evidence becomes more important, as do small numbers of incidents (in this case the argument seems to centre over what could be considered a statistically insignificant single event).

2) You state you see no reduction in the number of crashes. You will accept that this is your assumption based on flimsy data (as per point 1, not a criticism of your perspective). You cannot criticise poor data in one breath, then defend it in the next. This individual feels that they have seen an increase- and we have no way of saying whether this is true or not. IMPORTANT- I am not saying you are wrong- I am saying there is uncertainty.

3) Your equation is broadly correct- the total number of crashes is the sum of the number of crashes due to individual reasons (lets ignore combined reasons for clarity). 4)It would be fair to say that somewhere in that equation for 35M would be a factor "Q" that would be due to outside interference of another 35Meg user. This "Q" would be absent from 2.4. I have constantly repeated "all other things being equal" in my argument.

5) Due to very poor data it is difficult to quantify how much difference this "Q" factor makes in reality. There is a large degree of uncertainty, and vulnerability to statistical anomalies- as in this case. However- if you choose to interpret this factor as unimportant, you are making exactly the same assumptions (in an opposite direction) as someone that thinks that it is/might be. No one can prove their assumptions better than anyone else.

 

Finally, you have also completely failed to appreciate that I have stated several times that I do not agree with the ban.

[Martin Harris - Moderator]

Andy, I think your post makes it fairly clear that you and Erfolg are broadly in agreement despite some of the posts above. To sum up, I think we can all see a very small additional risk factor which is present when using 35 MHz and largely un-assessed risk factors from other aspects of signal propagation, reflectin, losses etc. when operating at different frequencies.

 

This whole matter centres on what is seen as an acceptable risk - and putting it into context, until a couple of years ago it was seen as reasonable to operate on 35 MHz at large public shows where any member of the public was able to buy a transmitter from trade or bring and buy stalls which had the potential to cause loss of control of whatever was in the air at the time.

 

I'd contend that the risks of operating on 35 MHz are probably reducing due to the reduction in the number of sets operating but with the pressure on the available frequency spectrum ever increasing, widespread club legislation against 35 MHz might lead to its withdrawal from modelling use. So what? Well, there are increasing problems using WiFi in built up areas on "our" 2.4 GHz band due to the explosion in use and as an open band, who knows what developments we might see in the future?

Edited By Martin Harris on 15/12/2011 10:29:04

[Ultymate]

I would have thought there are now bound to be more crashes on 2.4 simply due to shear weight of numbers of users. I don't think that correlates to faults with said 2.4. Over the years I've found a great tendency among modelers when a crash happens to scream "radio failure" when in reality it's more often than not installation issues or thumb trouble, but why oh why people are too embarrassed to own up is beyond me when often to knowledgeable onlookers the cause is obvious, good for a giggle though.