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Author Topic: 2.4GHz being affected - several makes.  (Read 2885 times)

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Offline Bad Raven

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2.4GHz being affected - several makes.
« on: September 24, 2017, 21:30:15 PM »
Today Sun 24/9/17 our club field seemed to be being swamped by some sort of interference never experienced by us before.

This affected people who are thoroughly competent builders/radio installers/pilots.

Affected planes (only fixed wing was bring used at the time) covered several differing makes of 2.4GHz frequency hopping radio.

Lets not have the "little kiddies" trolling posts about Spektrum here please, this was serious and significant interference inc makes with the best reputation in the industry.

Not heard any other experiences like this with 2.4GHz, but any RELIABLE info appreciated.
The user formerly know as Bravedan........... Well if Prince can do it....................


Offline firefox

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Re: 2.4GHz being affected - several makes.
« Reply #1 on: September 24, 2017, 23:16:00 PM »
Hi

You need to report this to the BMFA with as much detail as you can.

.
Nothing is foolproof to a sufficiently talented fool......

Offline itsme

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Re: 2.4GHz being affected - several makes.
« Reply #2 on: September 25, 2017, 08:59:23 AM »
Any factories opened nearby? Some machinery can cause problems on 35, not heard of it on 2.4 though.


Offline pooh

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Re: 2.4GHz being affected - several makes.
« Reply #3 on: September 25, 2017, 10:14:17 AM »
There are two ways interference can operate - the first is by simply competing with the wanted signal, by being on the same  frequency and masking the information in the wanted signal. Spread-spectrum systems are designed to prevent this happening by rapidly changing the operating frequency, so that any specific channel will only be interfered with for a very short time.

The second form of interference is caused by the overloading of the receiver, to the point that the semiconductors in the receiver are permanently switched "on", so no useful signals are detected. Any electronic equipment can be interfered with in this way (try holding your mobile phone near a stereo amplifier or PA system)

I would guess that it is the second type of interference, as several different makes/models were affected.

However, you need a lot of radio energy to cause this sort of problem. Microwave communications equipment could provide this sort of energy - I recall experiencing interference problems at one flying site which was almost certainly due to a narrow beam coming from a microwave dish, the interference only happened in line with the beam direction and height.

But whatever the source, it needs investigating.
Confucious he say "more than one aircraft in the same airspace leads to structural failure"

Offline paulinfrance

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Re: 2.4GHz being affected - several makes.
« Reply #4 on: September 25, 2017, 11:35:04 AM »
Can you give more information on the radio's and receivers, electric, petrol and methanol motors ?.
 maybe a sunspot !.
Mode 2 THE only way to fly


Offline onewinglow

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Re: 2.4GHz being affected - several makes.
« Reply #5 on: September 25, 2017, 11:45:00 AM »
Not sunspots, the face of the sun was quite for the 24/09. There is a sunspot coming round from the far side today. Additionally, we are in a minimum for sunspot activity. Could possibly be a grand minimum but will not be sure for a couple of more years.

Offline dart16

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Re: 2.4GHz being affected - several makes.
« Reply #6 on: September 25, 2017, 13:31:18 PM »
Might have been useful to have scanned the 2.4GHz band to see what signals were about at the time...

http://singlechannellersreunited.co.uk/phpbb3/viewtopic.php?f=9&t=721

I've built three of these now and can confirm they work, with the proviso that they will only indicate the signal THEY are receiving which is not necessarily what the signals are 40 feet up!

Offline FrankS

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Re: 2.4GHz being affected - several makes.
« Reply #7 on: September 25, 2017, 13:55:18 PM »
Did the interference cause the models to go into failsafe? if they did then that shows it was a corruption of the 2.4 transmission. If they didn't then it could have been an electromagnetic interference stopping the receivers from working correctly (as noted by Pooh above).

Was the interference across the site or in one specific location?

Offline Bad Raven

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Re: 2.4GHz being affected - several makes.
« Reply #8 on: September 25, 2017, 15:40:39 PM »
I am not going to state radio makes, it'll only induce the Trolls out from under the bridge. Suffice to say that investigation to date has shown there were FOUR makes of Radio involved, and two of these included two different protocols.

NO factories, a school and housing estate at approx a mile. There are inevitably mobile cell aerials on this estate.

Site is on farmland, no other users or public at the time of incidents.

Reported issues were in the main freezes of control action ("it's not responding" calls) without any obvious failsafe operation. Some of these were multiple in short order and aircraft were recovered before they crashed. A couple were longer term and held long enough that control was lost terminally.  All were well used well tested models.

Mix of Electric and Methanol powered. No petrol to my knowledge either in air or pits. Pits 20 feet behind pilots box.

Flying Site is quite small, 60 - 80 foot high mature tree edged and all flying takes place in one direction from pits, usually between 100 - 250 feet over tree boundary towards woodland and a field before the habitation starts..

The user formerly know as Bravedan........... Well if Prince can do it....................


Offline itsme

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Re: 2.4GHz being affected - several makes.
« Reply #9 on: September 25, 2017, 16:05:36 PM »
I am not going to state radio makes, it'll only induce the Trolls out from under the bridge. Suffice to say that investigation to date has shown there were FOUR makes of Radio involved, and two of these included two different protocols.

NO factories, a school and housing estate at approx a mile. There are inevitably mobile cell aerials on this estate.

Site is on farmland, no other users or public at the time of incidents.

Reported issues were in the main freezes of control action ("it's not responding" calls) without any obvious failsafe operation. Some of these were multiple in short order and aircraft were recovered before they crashed. A couple were longer term and held long enough that control was lost terminally.  All were well used well tested models.

Mix of Electric and Methanol powered. No petrol to my knowledge either in air or pits. Pits 20 feet behind pilots box.

Flying Site is quite small, 60 - 80 foot high mature tree edged and all flying takes place in one direction from pits, usually between 100 - 250 feet over tree boundary towards woodland and a field before the habitation starts..
Sounds like an investigation is needed. Anyone reported problems before or was it sudden? I would contact the BMFA to see if it is some illegal microwave signal.
.

Offline Bad Raven

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Re: 2.4GHz being affected - several makes.
« Reply #10 on: September 25, 2017, 16:11:21 PM »
NO problems before.
The user formerly know as Bravedan........... Well if Prince can do it....................

Offline itsme

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Re: 2.4GHz being affected - several makes.
« Reply #11 on: September 25, 2017, 17:20:08 PM »
NO problems before.
Anyone still flying there? Problems persisting? Needs looking in to.

Offline paulinfrance

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Re: 2.4GHz being affected - several makes.
« Reply #12 on: September 25, 2017, 17:43:21 PM »
Sounds like an investigation is needed. Anyone reported problems before or was it sudden? I would contact the BMFA to see if it is some illegal microwave signal.
.
You mean a caravanner making a cup of tea ?. :ev
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Offline Alan H

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Re: 2.4GHz being affected - several makes.
« Reply #13 on: September 25, 2017, 19:35:07 PM »
Some years ago back in the 27MHz days a flying site I was using at the time had a problem with a person on a nearby housing estate shooting models down with a Tx and some Xtals. Whilst it would be a lot harder to produce the necessary high power broadband source at 2.4GHz to have a similar effect it is not impossible.

Offline mart49

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Re: 2.4GHz being affected - several makes.
« Reply #14 on: September 25, 2017, 20:01:40 PM »
One potential source of the interference you describe is from legitimate Amateur radio operations. Amateurs can transmit 500 watts on 2.4Ghz, albeit into a directional antenna. However your description of your site makes this unlikely as such transmissions are line of sight, unless of course you are in a valley surrounded by hills and model were high enough to be in a LOS situation.

Offline Phil_G

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Re: 2.4GHz being affected - several makes.
« Reply #15 on: September 25, 2017, 23:46:32 PM »
Sounds like an investigation is needed. Anyone reported problems before or was it sudden? I would contact the BMFA to see if it is some illegal microwave signal.
But its an ISM junk band Bob, the authorities aren't interested, why would they be?  You could chase up a 35mhz complaint with Ofcom, and they are very protective with dedicated band allocations (or at least were then I worked on the RIS) but on 2.4 (or any ISM band) there is no case to answer!   ;D

« Last Edit: September 25, 2017, 23:47:59 PM by Phil_G »

Offline itsme

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Re: 2.4GHz being affected - several makes.
« Reply #16 on: September 26, 2017, 08:19:42 AM »
But its an ISM junk band Bob, the authorities aren't interested, why would they be?  You could chase up a 35mhz complaint with Ofcom, and they are very protective with dedicated band allocations (or at least were then I worked on the RIS) but on 2.4 (or any ISM band) there is no case to answer!   ;D
I didnt realise that. So with 2.4 we have lost our protection?


Offline Michael_Rolls

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Re: 2.4GHz being affected - several makes.
« Reply #17 on: September 26, 2017, 08:35:41 AM »
Are you near - I.e. within a couple of miles or so of any possible security risk on an occasional basis? Some years ago in 35 days I was chatting in what was my LMS with a guy whose club was near one of the. Palaces, Sandringham IIRC, when one morning session the several models in the air all piled in. Turns out there was bomb scare and the security people flooded the area with radio noise to cause a y remote controlled IEDs to detonate prematurely. Mike
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Offline firefox

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Re: 2.4GHz being affected - several makes.
« Reply #18 on: September 26, 2017, 12:05:57 PM »
One potential source of the interference you describe is from legitimate Amateur radio operations. Amateurs can transmit 500 watts on 2.4Ghz, albeit into a directional antenna. However your description of your site makes this unlikely as such transmissions are line of sight, unless of course you are in a valley surrounded by hills and model were high enough to be in a LOS situation.

I think you will find the maximum is 400 watts.

Not sure where you get the directional aerial from.

.
« Last Edit: September 26, 2017, 12:08:13 PM by firefox »
Nothing is foolproof to a sufficiently talented fool......

Offline dart16

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Re: 2.4GHz being affected - several makes.
« Reply #19 on: September 26, 2017, 12:41:26 PM »
But its an ISM junk band Bob, the authorities aren't interested, why would they be?  You could chase up a 35mhz complaint with Ofcom, and they are very protective with dedicated band allocations (or at least were then I worked on the RIS) but on 2.4 (or any ISM band) there is no case to answer!   ;D

It would appear that there is a case to answer Phil ...even on ISM bands.

https://www.ofcom.org.uk/spectrum/radio-spectrum-and-the-law/licence-exempt-radio-use/licence-exempt-devices/ofw311

5. Enforcement of regulations

To ensure Ofcom best serves consumers’ needs it broadly prioritises it efforts and resources when responding to reports of interference or market abuse. The first priority is safety of life services, the second other safety related business radio followed by the remainder.

Ofcom defines the priorities of model control equipment enforcement as:

...ensuring that non-compliant radio equipment is kept off the market;
...ensuring that the use of radio and radio frequencies throughout the spectrum conforms to licence requirements (licence exemption regulations); and
...investigating and taking action to prevent undue interference.
Ofcom’s Field Operations teams are located throughout the country and are happy to provide local advice including assistance to ensure users stay within the law. Ofcom has the power to take enforcement action against people who: cause interference; use inappropriate equipment; and place non-compliant equipment on the UK market. Penalties for breaches of the Wireless Telegraphy regulations range from informal warnings, formal cautions, through to fines and imprisonment.

Offline Phil_G

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Re: 2.4GHz being affected - several makes.
« Reply #20 on: September 26, 2017, 13:49:21 PM »
It would appear that there is a case to answer Phil ...even on ISM bands.
...investigating and taking action to prevent undue interference.
Its extremely unlikely that its 'undue interference' and will almost certainly be legitimate use.  Thers no harm in trying but I would expect Ofcom to give ISM band conflicts a relatively low priority.
Cheers
Phil

Offline firefox

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Re: 2.4GHz being affected - several makes.
« Reply #21 on: September 26, 2017, 14:25:05 PM »
FYI

Amateur radio operations use frequencies 2.310 to 2.450 GHz whilst we use 2.400 to 2.4835 GHz for model aircraft.

So the overlap is only from 2.400 to 2.450 GHz, ie 0.050 GHz.

On the other hand WiFi operates from 2.4000 GHz to 2.500 GHz which covers the whole model band!

.
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Offline dart16

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Re: 2.4GHz being affected - several makes.
« Reply #22 on: September 26, 2017, 16:47:09 PM »
I am not going to state radio makes, it'll only induce the Trolls out from under the bridge. Suffice to say that investigation to date has shown there were FOUR makes of Radio involved, and two of these included two different protocols.

might be interesting to know which protocols were affected and which protocols, if any, were not affected?


Flying Site is quite small, 60 - 80 foot high mature tree edged and all flying takes place in one direction from pits, usually between 100 - 250 feet over tree boundary towards woodland and a field before the habitation starts..

So the affected models were between the Tx and the habitation, perhaps take a drive around the housing estate looking up for dishes pointing your way?

No military activity I trust...2.4835 - 2.5 GHz     UK95 - Limited to land and naval radars below 2550 MHz and naval radars below 2600 MHz.

Offline Phil_G

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Re: 2.4GHz being affected - several makes.
« Reply #23 on: September 26, 2017, 16:58:52 PM »

Offline Bad Raven

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Re: 2.4GHz being affected - several makes.
« Reply #24 on: September 27, 2017, 08:28:20 AM »
Thanks for all posts, no time to reply to all comments now, but thanks for input.

No security sites, no military sites, nothing known new to the area.

Yesterday at the site there was NO issues at all with any make used, and I alone used four differing makes and six differing Tx.

After static tests and ground range checks, I put a ST models Blaze to extreme boundary at 400' (Vario reading) and NO issues.

I put a parkfly single aerial Orange DSM2 Rx up to 350 feet and 200 feet plus ground away from a DX9, no issues. I trawled back and fore low and high, no issues.

Whatever happened Sunday, not there yesterday.

Rogue Transmitter possibly?  Several Tx there yesterday used Sunday, inc two of the affected ones, both clear.
The user formerly know as Bravedan........... Well if Prince can do it....................

Offline Bad Raven

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Re: 2.4GHz being affected - several makes.
« Reply #25 on: September 27, 2017, 08:30:19 AM »
might be interesting to know which protocols were affected and which protocols, if any, were not affected?

And release the Trolls?
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Offline itsme

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Re: 2.4GHz being affected - several makes.
« Reply #26 on: September 27, 2017, 09:14:19 AM »
And release the Trolls?
Well, I bet it was a Sp*c*r*m transmitter......(free! Free! Free!)


 

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