Spectrum Analysers in UK

Droider

Droider

Drone Enthusiast
The latest Information notice document from the CAA mentions checking the airwaves for possible interference that may cause loss of aircraft control with a spectrum analyser.

Is this practical, possible, if so what should be used?

Dave

'Radio Frequency (RF) interference. Pilots should take account of the possible reduction in operating range in an urban environment due to the heavy use of communications (mobile telephone, WiFi etc.) equipment and other sources of electromagnetic spectrum / RF interference. Mitigation for the consequences of weak or lost GPS signal due to masking by buildings should be considered along with the general RF saturation level. The use of a spectrum analyser is recommended to assist in assessing the level of local electromagnetic and RF congestion in the 2.4 GHz or 35 MHz frequency range.'
 



Droider

Droider

Drone Enthusiast
Thanks. Ill kook in to it a bit more but what kind of range are we looking at here, for instance I would have thought it is only useful for your location, if your aircraft is 400m away surly it has to be different from where you are controlling the aircraft from..

Dave
 

ZAxis

ZAxis

Member
You're spot on Dave. It will only give a picture in the area of takeoff at ground level. It will also only look at the 2.4GHz band. Our only experience with control being interfered with was not 2.4 related, it was cell phone frequencies from a set of masts at the far end of a flight.
RF interference is a worry, especially in urban areas but it's the whole frequency range involved. In rural areas, keep an eye out for remote radar sites, microwave relay towers, military exercise areas. Then there's GPS spoofing by the military or individuals.
The best thing is to be able to recognise the effect of interference and be able to react to it. That takes training and experience.

To those with analysers, how would you decide there is a potential problem. Is it a judgement or a hard and fast set of parameters laid down in your ops manual?
Has anyone direct experience of a malfunction due to RF interference? Has anyone made the decision to cancel a flight because of it?

Andy
 

JimM

JimM

Member
Thats the limiting factor.
As a starting point, a check from your tx location will at least tell you if your tx signal is being swamped by environmental rf noise from its location. Going from there, in a particularly dense congested area, you could go as far as sampling around the site, even to the extent of checking signal levels from your tx switched on and off by an assistant while you check from several buildings on different floors around the site to see if your tx is getting through the rf swamp. To be really sure - (and this is really thinking on the wild side now) a small hand tethered balloon with a cradle holding the analyser and a small micro camera recording the display (with time recorded ) could set to record the signal levels while switching the tx on and off at specific times could be used to walk the site . Up to the max height you fly wouldn't be practical probably but even limited height sampling could at least give a much clearer indication if the signal pattern that is present. Just thinking aloud here... There are many considerations of course and I'm sure that there will be (I hope there will be) other ideas- some less off the wall than these and more sensible and less time consuming. here's a thought, If a balloon is used for these tests, is it a tethered aircraft and Is PFAW and therefore a flight test required - I assume it would be :) Thoughts and comments please..
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
Hi all,

I use the same analyser as mentioned above (RF Explorer). I know next to nothing about this kind of thing but scan at every location nonetheless. I am just looking for strong interference that could swamp the transmitter signal. To date, I have not found anything that would stop me from flying. Even right next to a broadband wireless router the effects are quite narrow and short range compared to the transmitter output.

For me it's just another piece of mind thing. Nothing is perfect, and we can only test what we can test before the testing becomes more time consuming than the flight itself.
 

Droider

Droider

Drone Enthusiast
The best thing is to be able to recognise the effect of interference and be able to react to it. That takes training and experience.
Click to expand...

Totally agree. The CAA seem to be concerned about the volume of applications, most wanting to film in congested areas. I think this is another thing they have introduced to possibly help reduce the risk of the relatively inexperienced operators, and with no disrespect people that have just gained permissions are inexperienced. The CAA made that perfectly clear at the meeting in London. They will be looking at companies experience and use that as a just part of the process to allowing exemptions, especially in London.

Talking of which anyone recently been granted exemptions in London? Anyone flown over the Thames?

Dave

Dave
 


kloner

kloner

Aerial DP
we use the rf explorers as well. we run them pre flight for a time, take note of the flor, we turn on our radios and make sure we get signal, power and look at the waterfall to make sure were looking right then we monitor in flight. Biggest thing it caught was a dying ezuhf transmitter, the depth of the signal got really thin, noticed it on a gig. Another time we caught super tall rf during the scout, similar to mentioned above, cell tower stuff..... other times is more obvious when you walk by signs like these.

20140108195724-c04c2c0e.jpg
 


Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
Droider said:
Totally agree. The CAA seem to be concerned about the volume of applications, most wanting to film in congested areas. I think this is another thing they have introduced to possibly help reduce the risk of the relatively inexperienced operators, and with no disrespect people that have just gained permissions are inexperienced. The CAA made that perfectly clear at the meeting in London. They will be looking at companies experience and use that as a just part of the process to allowing exemptions, especially in London.

Talking of which anyone recently been granted exemptions in London? Anyone flown over the Thames?

Dave

Dave
Click to expand...

Apparently NATS aren't allowing any over 7kg flights to take place in London. A few people have said this.
 

Carapau

Carapau

Tek care, lambs ont road, MRF Moderator
I use a Wi-spy which has been excellent ie it is very easy to read and understand the picture of the environment that it is scanning. Droider, you are right about the ideal of having the spectrum analyzer where your aircraft is going to be and not at the ground point but my view is that if I wasn't using an analyzer what else have I got to help me understand the flying environment before I take off? Range test I guess but that's about it. There are no hard and fast rules as to when to take off or not- its a total judgement call. I guess the spectrum analyzer helps you make a MORE informed decision than just looking around. Experience definitely makes a big difference too no doubt there.
 

JimM

JimM

Member
Benjamin Kenobi said:
Apparently NATS aren't allowing any over 7kg flights to take place in London. A few people have said this.
Click to expand...

I had heard that that safety cases for >7kg were very very difficult to establish nowadays. That should change around October when the >7kg advisories are expected to he published.
 


Droider

Droider

Drone Enthusiast
Benjamin Kenobi said:
Apparently NATS aren't allowing any over 7kg flights to take place in London. A few people have said this.
Click to expand...
MM Cheers Ben..

I will ring them in the morning too see what the score is… OBTW I have had my moderator status removed and could be banned the next time Bart logs on!.. Ill keep,in touch though

dave
 

Bartman

Bartman

Welcome to MultiRotorForums.com!!
Droider said:
...............OBTW I have had my moderator status removed and could be banned the next time Bart logs on!.. ..............
Click to expand...

nothing that i've said should lead you to believe that you'd be banned but if you feel better traipsing about the site posting this stuff then carry on.
 

1lifefilm

1lifefilm

Member
Hi Benjamin
I'm new to the forums, about to do the BNUCS theory in July! Can you tell me more about these 7kg advisories and how they might work?
cheers
Simon
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
Hi mate,

Not sure quite what you're asking but currently....

NATS are not granting permission for over 7kg flights in ATZ's as advised by their legal department. They have a meeting with the CAA next week to decide how to advise ATC's how to handle UAV flights. Things should be back to normal after that.

I'm a sub 7kg man so can fly in ATZ's to my hearts content, probably why I've been having so many London jobs recently (I hate flying in congested areas!).

Normally, you would fill out the online form for an Enhanced Non-Standard Flight Clearance from the NATS website. I still do this and am always accepted but over 7Kg flyers get the reply:

“Thank you for the notification of your intended flight. The flight is required to take place in accordance with ANO Articles 137, 138 and 166 of the Air Navigation Order. You are intending to fly within [controlled airspace/an ATZ] and there is a collision risk for which you are responsible and liable for”.

But no actual approval or permission will be given.

Yeah, I don't understand that either. After the meeting next week I will fill you in. I am trying to organise a night flight on the thames near the houses of parliament for an over 7kg aircraft. I hope they resolve this issue soon!
 

1lifefilm

1lifefilm

Member
Thanks for getting back mate...appreciated. I'd also heard something about future airworthiness requirements for flying any over 7kg machine in any congested area (controlled airspace or uncontrolled), have you heard anything to this effect?
cheers
Simon
 

You must log in or register to reply here.
Top