CCTV radio interference

Hi all, this one is for the cctv gurus

Installing a cctv system with 14 HiKVision is cameras. 13 of which are via wireless bridges as it is a caravan site.

• One camera is Poe hardwired back to the nvq and has no issue.
• There are 3 base station radio receivers which are streaming 4-5 cameras each
• the basestation covering the local cameras seems to be fine
• the other two base stations have had all cameras working but are intermittent

The radio manufacturer are scratching there heads as they think there is some sort of interference or something maybe wrong with the network switches, just wondering if anyone has ever had a similar issue and been able to sort it? Before we cough up £600 for a site visit from them!

Forgive me I am not a cctv installer so my knowledge is not great but any help gratefully recieved

So the cameras causing problems are wireless?

I don’t know enough about cctv myself to give a definitive answer, but I was involved in a system where one camera signal was radio... or a microwave link?? Had to be line of sight.
The transmitter was mounted to a lamppost which would sway in the high winds and knock off the signal...
Caravans driving past also caused a problem... whether the signal was bouncing off the roof of the vans and caused interference.

maybe just put this on loud. ( Roy Wood was born 10 days before me, so I consider him as a contemporary). Sod the cameras.

littlespark said:

So the cameras causing problems are wireless?

I don’t know enough about cctv myself to give a definitive answer, but I was involved in a system where one camera signal was radio... or a microwave link?? Had to be line of sight.
The transmitter was mounted to a lamppost which would sway in the high winds and knock off the signal...
Caravans driving past also caused a problem... whether the signal was bouncing off the roof of the vans and caused interference.

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yes, there is line of sight between the transmitter and receiver but when observing the activity of the radios via their software, they seem to drop in and out constantly.
some cameras and radios combine into a network switch before they get transmitted back, wondering whether its worth getting a better one?

telectrix said:

maybe just put this on loud. ( Roy Wood was born 10 days before me, so I consider him as a contemporary). Sod the cameras.

Click to expand...

telectrix said:

maybe just put this on loud. ( Roy Wood was born 10 days before me, so I consider him as a contemporary). Sod the cameras.

Click to expand...

I shall try this approach with the gaffer first thing tomorrow morning. ?

MR T 123 said:

Hi all, this one is for the cctv gurus

Installing a cctv system with 14 HiKVision is cameras. 13 of which are via wireless bridges as it is a caravan site.

• One camera is Poe hardwired back to the nvq and has no issue.
• There are 3 base station radio receivers which are streaming 4-5 cameras each
• the basestation covering the local cameras seems to be fine
• the other two base stations have had all cameras working but are intermittent

The radio manufacturer are scratching there heads as they think there is some sort of interference or something maybe wrong with the network switches, just wondering if anyone has ever had a similar issue and been able to sort it? Before we cough up £600 for a site visit from them!

Forgive me I am not a cctv installer so my knowledge is not great but any help gratefully recieved

Click to expand...

What frequency are the wireless bridges operating on ?. If you are on 2.4 or 5Hz radios then first off I would use one of the many WiFi analyser apps that are available to check for any co-located or co-channel radio interference.
The issue with both the 2.4 & 5 GHz frequency bands is they are in open use and for something like a caravan site using those frequencies for infrastructure equipment could give problems with the site users bringing mobile phones and other WiFi equipment on to the site
If you are using any other frequency then you would need a spectrum analyser to locate the source of the interference
With regard to intermittent interference I installed a 2.4GHz radio link in Oswestry many years ago and it kept dropping out we eventually located the interference source as the local wood merchants who had a very leaky microwave wood drying kiln that they used 3 or 4 days a week

littlespark said:

So the cameras causing problems are wireless?

I don’t know enough about cctv myself to give a definitive answer, but I was involved in a system where one camera signal was radio... or a microwave link?? Had to be line of sight.
The transmitter was mounted to a lamppost which would sway in the high winds and knock off the signal...
Caravans driving past also caused a problem... whether the signal was bouncing off the roof of the vans and caused interference.

Click to expand...

Probably caused by fresnel zone incursion if it was a microwave radio, normally caused by not mounting the units high enough to avoid incursion into the radio "bubble" of passing objects

They are silvernet echo radios which I’ve read to be a frequency of 5Ghz.
When initially configuring there is the option to use uk band A, B or C, initially put it on band b but changed to band c to see if it solved the problem but no joy.

Like you say with being a caravan site there is various other radio equipment dotted around such as WiFi etc.

I will try downloading one of the apps you suggested, hopefully that will narrow down the potential cause of the problem

Not looked at the info on the radios you are using yet as I'm out on site so not up to speed on them
Are you using point to point or a point to multi point setup for this system

UNG said:

Not looked at the info on the radios you are using yet as I'm out on site so not up to speed on them
Are you using point to point or a point to multi point setup for this system

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Using a point to multipoint like so. The crosses are representing the radios and the bs (base stations) are the receivers which are hardwired back to the nvr via a network switch.

While this on the surface is a CCTV problem it would appear the issue is more related to the method of transporting the video to the NVR which is a radio / data network issue

So a few questions

MR T 123 said:

Installing a cctv system with 14 HiKVision is cameras. 13 of which are via wireless bridges as it is a caravan site.

• One camera is Poe hardwired back to the nvq and has no issue.
• There are 3 base station radio receivers which are streaming 4-5 cameras each
• the basestation covering the local cameras seems to be fine
• the other two base stations have had all cameras working but are intermittent

Click to expand...

Who was responsible for the LOS survey, design, installation and commissioning of the radio and data network

Is the CCTV / radio set up in it's own network (subnet) with fixed IP addresses or is it running on DHCP
Also is the CCTV part of the rest of the site network infrastructure

MR T 123 said:

The radio manufacturer are scratching there heads as they think there is some sort of interference or something maybe wrong with the network switches, just wondering if anyone has ever had a similar issue and been able to sort it? Before we cough up £600 for a site visit from them!

Click to expand...

What does the radio manufacturers site visit charge cover is this just to look at the system and offer advice or are they going to do any hands on work. While they are scratching their head it would be interesting to know if they have made any suggestions as to why there are problems

MR T 123 said:

Forgive me I am not a cctv installer so my knowledge is not great but any help gratefully recieved

Click to expand...

So having established your CCTV experience is very limited what level of experience do you or anyone else involved on the project have of data networks, installation of radio networks and the integration and commissioning of them, I'm assuming that no specialist sub contractors have been employed on this project to set up the radio network and data switches

MR T 123 said:

They are silvernet echo radios which I’ve read to be a frequency of 5Ghz.
When initially configuring there is the option to use uk band A, B or C, initially put it on band b but changed to band c to see if it solved the problem but no joy.

Like you say with being a caravan site there is various other radio equipment dotted around such as WiFi etc.

I will try downloading one of the apps you suggested, hopefully that will narrow down the potential cause of the problem

Click to expand...

If all you have set is the operating band on the radio kit then it sounds like you do not have a properly structured and commissioned radio network. The radio links used when used in isolated single link scenarios would more than likely operate perfectly well in out of the box as a plug and play solution.
The set up you have with multiple radio links needs more structured programming and channel separation

MR T 123 said:

Using a point to multipoint like so. The crosses are representing the radios and the bs (base stations) are the receivers which are hardwired back to the nvr via a network switch.
View attachment 85331

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Although the diagram is probably not a true topographical representation of the site I'm not understanding why you have 2 point to multi point links in parallel from the cafe to the reception

I suspect that some of the issues are down to poor deployment and set up of the radios in the absence of network test kit I think a laptop used at some strategic points to fire some loaded pings across the network to the NVR might help to identify some of the problems

Agree on that - all cameras have at some point appeared on the NVR monitor so know that that side of things is working.

• The radios are on their own subnet - each radio and each basestation having its own Ip address
• It has not been integrated into the site network infrastructure
• I believe the site visit for that amount was for a site survey, but if interference is the problem then I would assume that they would have equipment for detecting this. Initially they suggested spacing out the basestations with a gap in between each, which has been done, but not solved the problem.
• The radio settings were done by the manufacturer - they have set all of the parameters themselves to what they know should work - hence the head scratching now that it doesn't.
• The reason for having multiple links in parallel is due to the radios capability of having a maximum amount of cameras running through each wireless bridge, hence why there are 4 basestations at reception rather than just one.

Currently we are looking at upgrading the network switches as we are suspicious that they aren't up to the task of handling the traffic of that many cameras

MR T 123 said:

Agree on that - all cameras have at some point appeared on the NVR monitor so know that that side of things is working.

• The radios are on their own subnet - each radio and each basestation having its own Ip address
• It has not been integrated into the site network infrastructure

Click to expand...

How does the site network infrastructure connect across the site is this on radio links as well

MR T 123 said:

• I believe the site visit for that amount was for a site survey, but if interference is the problem then I would assume that they would have equipment for detecting this. Initially they suggested spacing out the basestations with a gap in between each, which has been done, but not solved the problem.
• The radio settings were done by the manufacturer - they have set all of the parameters themselves to what they know should work - hence the head scratching now that it doesn't.

Click to expand...

Having already deployed radio kit doing a site survey at this stage is a bit like putting the cart before the horse as a clear line of site with no fresnel incursion is a must before considering a radio solution of this type. I think you need to establish exactly what they will do on this site visit if you are looking at taking this route, I would like to think they would have a spectrum analyser to at least identify any potential sources of interference.

As all the set up of the radios was done by the manufacturer I assume prior to despatch to site have any checks been done to confirm the configuration is correct as they were powered up, seen it before were radios were pre-programmed and the configuration was not saved or for some reason the default configuration was loaded.
I would not be to happy having been sold a radio system that should work and then being asked for £600 for them to attend site in an attempt to sort out the problem, although having gone to sites to fix none existent radio faults was one of my pet hates

MR T 123 said:

• The reason for having multiple links in parallel is due to the radios capability of having a maximum amount of cameras running through each wireless bridge, hence why there are 4 basestations at reception rather than just one.

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On your parallel links is there a reason why you not using an ST to ST point to point arrangement rather than the BS to ST set up you have which is point to multipoint link. How much bandwidth do these cameras need and what data rate are the radios running at to need two links in parallel

MR T 123 said:

Currently we are looking at upgrading the network switches as we are suspicious that they aren't up to the task of handling the traffic of that many cameras

Click to expand...

Before you start swapping out kit have you done any actual end to end data testing to confirm what the data throughput is and what the bit error rate is, I would test the radio links on their own and then add in the network switches to ascertain where the problem lies before swapping any kit. If the system works and intermittently drops out then that would suggest the kit is capable of doing it's job


I assume that this site is somewhere close to the location given in your profile, if that is the case I would have been a bit weary of using any 5GHz equipment as part of an infrastructure system in that area due to possible / probable interference from sources nearby

Apologies for not getting back sooner.

After returning to site I set up an extra wireless link to help with alignment/line of sight and also replaced the network switches. So far this appears to have sorted the problem.
I think I've probably over complicated an issue which didn't exist but fingers crossed.

Thanks for the feedback UNG

Glad you got it sorted

MR T 123 said:

The reason for having multiple links in parallel is due to the radios capability of having a maximum amount of cameras running through each wireless bridge, hence why there are 4 basestations at reception rather than just one.

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Hmm, I can't think of any wireless kit I'd consider putting in that was so limited. If you have two base stations close together, then with decent kit you'd just use one. Two will need to be configured to separate (non-ovelapping) channels* otherwise they will actually have worse throughput than one link.

MR T 123 said:

Currently we are looking at upgrading the network switches as we are suspicious that they aren't up to the task of handling the traffic of that many cameras

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Unlikely.

I'm with UNG, sounds like a very questionable design.

Also, you need to be aware that you can't just randomly pick band A, B, or C - there are rules and fixed outdoor equipment can only use one of them, and you may need a licence. At a previous employer we had an FWA licence because we used wireless to connect some clients to the internet.
According to this Ofcom document, you can use band B at low power, or band C with a licence.

* But note that the Ofcom document is clear that you cannot manually set channels (frequencies) on your kit - they must be dynamic. So if you have two sets of wireless kit, you stand a chance of them channel hopping (depending on what other users are doing in the vicinity) and actually causing interference within your own network.


And something else has just popped into my head. I couldn't follow your diagram, but if you have multiple Wifi enabled cameras connecting back to 2 bases - it's not impossible that the devices are (apparently) randomly switching between bases which can cause momentary drop outs.

Have you tried turning off the cameras? I was working on a construction site, and we were having problems, it turned out the aerials on some radios were damaged which was affecting the rest, you only need one bad transmitter to stop rest working.