FPV Interference on 2.4Ghz

The latest information and advice on installing and using 2.4 Ghz systems in over 20 Kg model aircraft
Bob Thompson1894
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Re: FPV Interference on 2.4Ghz

Postby Bob Thompson1894 » March 1st, 2011, 12:22 am

Mike altham wrote:Hi

As Alan said they should be buddy linked and be in sight of the other pilot.

If you are running 2.4 on the transmitter and rx for the camera. You have to use 35 MHz radio as the 2.4 will swamp the radio 2.4 signal.

There is 5.8 ghz for camera and 433 UHF but this needs a HAM license to use in the Uk plus it is a military frequency I think.

FPV flying is not covered under Bmfa insurance. Little known to some FPVers that you have to get separate insurance which is £15 a year. This covers FPV Flying upto 5 million insurance.

I have one of these with all the gear. We have a FPV slot at our clubs so we know it will not affect anyone.
The 35 MHz will start losing signal at around a mile.

Some people on the forums have a normal 149 dp rx and add another 3 lengths of aerial onto the rx.
These have then been flown to around 4.5 miles away on standard 35 MHz

Ok if you are in the middle of nowhere but not in the area where other clubs are.
And the safety pilot can see this at 4.5 miles? God help us.

Barry Bennett
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Re: FPV Interference on 2.4Ghz

Postby Barry Bennett » March 1st, 2011, 9:34 pm

Must dig that olde control line model out of the attic. 8-)
Last edited by Barry Bennett on March 2nd, 2011, 2:33 pm, edited 1 time in total.

Andy Boylett
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Re: FPV Interference on 2.4Ghz

Postby Andy Boylett » March 1st, 2011, 9:47 pm

I was thinking of fitting a dual, super tripple 10,000mwatt tranmitter module to my 2.4ghz transmitter. Then I could kill any fpv that got too close :D

Glenn Masters
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Re: FPV Interference on 2.4Ghz

Postby Glenn Masters » March 1st, 2011, 10:41 pm

. . . . now you're talking ! ! nice one . . .

Mike altham
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Re: FPV Interference on 2.4Ghz

Postby Mike altham » March 2nd, 2011, 7:52 am

Exactly, some on the internet even have spotters with binoculars

My theory is, if everyone is swapping to 2.4ghz then there will be less chance of getting shot down on 35mhz :D

2.4ghz will be in the Nimrod so hopefully it will be ok. I still dont trust it 100%. In 14 years I have not had any radio failure or interference on 35mhz touch wood :)

Mike.

Bob Johnstone
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Re: FPV Interference on 2.4Ghz

Postby Bob Johnstone » March 6th, 2011, 9:48 pm

The chance of an incident is perhaps small, we should still be a little wary unless it can be properly shown not to be a problem. I shall not panic.

433Mhz. There is a very small allocation in the Band for Scientific and Medical use which is also used by vehicle access fobs. Amateur Radio "Hams" are not allowed to use Video Transmissions from an aircraft as has been suggested.

Mike altham
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Re: FPV Interference on 2.4Ghz

Postby Mike altham » March 7th, 2011, 7:45 am

Hi ,

433 mhz is used in different countries but not legal here in the UK.

There is a legal frequency of 459mhz that is allocated to model aircraft which the FPV cameras etc are going to from some manufacturers as they can get longer distances.

Air-to-ground line of sight and reliable transmission distance of up to 10000m(500mW); uses GFSK modulation mode.
Carrier frequency: 433 MHz can be used - this is an ISM band in many countries (not in the UK, Amateur Licence is required))
Alternatively by setting the unit to channels 9, 10 or 11 it will operate in the 459MHz band which is reserved for model control in the UK. (Amateur licence may still be required).
Provides 16 channels
Interface: TTL/RS232/485 by the user select (required custom);
Receiver sensitivity:-123dBm
Interface rate: 1200/2400/4800/9600/19200bps/38400bps
Channel rate: 1200/2400/4800/9600/19200bps/38400bps
Transceiver Conversion Time<20ms
Can be used for point to point, point to multipoint, multi-point to point communications and many other combinations
Transparent data transmission
Auto-filter out false data generated by the air, long-term reliability is good, very low failure


Mike.

Glenn Masters
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Re: FPV Interference on 2.4Ghz

Postby Glenn Masters » March 7th, 2011, 7:59 am

. . . . . . Eh ? . . . .

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Dave Parry
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Re: FPV Interference on 2.4Ghz

Postby Dave Parry » March 7th, 2011, 8:42 am

Glenn Masters wrote:. . . . . . Eh ? . . . .


Exactly Glen, just what I was thinking.
LMA Journal Editor :geek:
You can contact me at: lma.journal.newsdesk@gmail.com or Dave.Parry07 on Image

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Denis Brown
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Re: FPV Interference on 2.4Ghz

Postby Denis Brown » March 7th, 2011, 7:14 pm

Dave Parry wrote:
Glenn Masters wrote:. . . . . . Eh ? . . . .


Exactly Glen, just what I was thinking.

Think I might go back to my Hornby train set :o :evil:

adrian west
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Re: FPV Interference on 2.4Ghz

Postby adrian west » March 12th, 2011, 9:51 am

http://www.youtube.com/watch?v=Bmw6KPrpuCI
found this on you tube comments sum it up and the one at the end of the video

Bob Thompson1894
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Re: FPV Interference on 2.4Ghz

Postby Bob Thompson1894 » March 12th, 2011, 12:42 pm

adrian west wrote:http://www.youtube.com/watch?v=Bmw6KPrpuCI
found this on you tube comments sum it up and the one at the end of the video

Yep, typical illiterate attitude- 'they was stuck in the past and wouldnt let me fly'.

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Denis Brown
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Re: FPV Interference on 2.4Ghz

Postby Denis Brown » March 13th, 2011, 9:57 am

Well I have watched that video and one or two others and I find it quite boring. Am I missing out on something?
Sooner watch Andy Wynns grass chopping Mustang at close hand :mrgreen:

Sam Boylett
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Re: FPV Interference on 2.4Ghz

Postby Sam Boylett » May 12th, 2013, 10:54 pm

At last years Elvington, DSM2 models were dropping left right and centre. We thought it was to do with the large aerial at the airfield occasionally transmitting at high amplitude and knocking out our signals if we were unlucky. It hit me twice and hit others using DSM2. Any model on DSMX or other frequency hopping 2.4 were fine.

Now 35Mhz is banned, I wonder how long it is before non-frequency hopping transmitters are banned? DSM2 is fine just around other 2.4 transmitters, but illegal FPV and (I'm assuming legal) airfield equipment can swamp them. Worst part is they don't even go into failsafe in this situation (neither of mine did, yet they both passed ground tests) :!:

DSM2 test: http://youtu.be/Vy7Gg6Tj57Q?t=2m39s

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Rob Buckley
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Re: FPV Interference on 2.4Ghz

Postby Rob Buckley » May 13th, 2013, 6:33 am

Sam,

If you (and others) were having such serious sounding radio problems at a public show, did you formally report it to the LMA (ie me)?

Rob
LMA Secretary - I've got a reasonable idea where you live!

Sam Boylett
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Re: FPV Interference on 2.4Ghz

Postby Sam Boylett » May 13th, 2013, 8:19 am

Nope, didn't think to report it then but if you want a formal report I could give you one with all the details.

Ken Bones
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Re: FPV Interference on 2.4Ghz

Postby Ken Bones » May 13th, 2013, 11:37 am

Sam Boylett wrote:At last years Elvington, DSM2 models were dropping left right and centre. We thought it was to do with the large aerial at the airfield occasionally transmitting at high amplitude and knocking out our signals if we were unlucky. It hit me twice and hit others using DSM2. Any model on DSMX or other frequency hopping 2.4 were fine.

Now 35Mhz is banned, I wonder how long it is before non-frequency hopping transmitters are banned? DSM2 is fine just around other 2.4 transmitters, but illegal FPV and (I'm assuming legal) airfield equipment can swamp them. Worst part is they don't even go into failsafe in this situation (neither of mine did, yet they both passed ground tests) :!:

DSM2 test: http://youtu.be/Vy7Gg6Tj57Q?t=2m39s



Interesting!

And I am NOT taking the wee wee.

Bonzey

Bob Thompson1894
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Re: FPV Interference on 2.4Ghz

Postby Bob Thompson1894 » May 13th, 2013, 1:10 pm

Sam Boylett wrote:At last years Elvington, DSM2 models were dropping left right and centre. We thought it was to do with the large aerial at the airfield occasionally transmitting at high amplitude and knocking out our signals if we were unlucky. It hit me twice and hit others using DSM2. Any model on DSMX or other frequency hopping 2.4 were fine.
I am at a loss what to think here. Models were 'dropping left, right and centre' and yet nobody brought this to the attention of the LMA in any way? The flight line crew did not query or investigate these 'crashes'? Are you avin a laff? :?:

paul hughes
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Re: FPV Interference on 2.4Ghz

Postby paul hughes » May 13th, 2013, 1:23 pm

and why has it taken nearly 12months to mention the problem, If there is one!
I flew on spectrum dsmx with no problems, Abit more expensive than dsm2 but worth the extra £20

Bob Thompson1894
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Re: FPV Interference on 2.4Ghz

Postby Bob Thompson1894 » May 13th, 2013, 1:51 pm

'didnt think to report it' seems a very odd thing, and as Paul said, its a long time ago- care to elaborate?


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