Ofcom - How they trace location?

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Ofcom - How they trace location?

Post by piratefm » Sat Jul 09, 2022 12:34 pm

Just want to understand how Ofcom can track a pirate broadcasters antenna location.

So, how does Ofcom locate a pirate broadcaster, what sort of equipment would they likely be using?

And how far can Ofcom actually get to the location of where the antenna is? Does their equipment take them precisely to the antenna location or does it just get them within an area and then they go looking?

And lastly, do they have the ability to monitor the spectrum right across the UK or just within certain locations. For example would a low powered station say 1-5watts be something immediately picked up when the transmitter is turned on in an out of city location?

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Re: Ofcom - How they trace location?

Post by alfaeire » Sat Jul 09, 2022 12:38 pm

Using triangulation it's pretty easy.

Say you are in a small town broadcasting, they would go to 3 points around the town with a directional antenna, then draw a line on a map indicating the strongest signal strength.
When done from 3 plots, they all cross on the map at your location or surrounding. Then they have to look out for towers and antennas. It can be done in as little as a hour or 2.

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Re: Ofcom - How they trace location?

Post by Roobru » Sat Jul 09, 2022 1:06 pm

You can actually do triangulation from two point. So long as the lines cross at some point, you have your location.

I'm sure I read that there is a site somewhere which can monitor broadcasts from long distances away around the UK, but obviously, if the power isn't strong, then the chance of picking up a low powered rig is remote. You would probably find most pirates are reported to the authorities by other legal stations ect than being searched for on the FM dial by the authorities.

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Re: Ofcom - How they trace location?

Post by piratefm » Sat Jul 09, 2022 1:35 pm

alfaeire wrote: Sat Jul 09, 2022 12:38 pm Using triangulation it's pretty easy.

Say you are in a small town broadcasting, they would go to 3 points around the town with a directional antenna, then draw a line on a map indicating the strongest signal strength.
When done from 3 plots, they all cross on the map at your location or surrounding. Then they have to look out for towers and antennas. It can be done in as little as a hour or 2.

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I didn’t realise it was this simple. So it seems it gets them to an approximate location then they just need to have a little look themselves to pin point it. Interesting!

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Re: Ofcom - How they trace location?

Post by piratefm » Sat Jul 09, 2022 1:41 pm

Roobru wrote: Sat Jul 09, 2022 1:06 pm You can actually do triangulation from two point. So long as the lines cross at some point, you have your location.

I'm sure I read that there is a site somewhere which can monitor broadcasts from long distances away around the UK, but obviously, if the power isn't strong, then the chance of picking up a low powered rig is remote. You would probably find most pirates are reported to the authorities by other legal stations ect than being searched for on the FM dial by the authorities.
Is it the Monitoring station at Baldock you’re thinking of?
I don’t think me switching a 1-5watt rig on would be picked up by this as I’m rather far away from this site. I could be wrong though! Also makes me wonder if they have smaller sites dotted around that link back.

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Re: Ofcom - How they trace location?

Post by Albert H » Sat Jul 09, 2022 1:49 pm

There are several ways you'll be found:

Interference Reports
cause the "authorities" to come out and try to find its source.

Complaints from other broadcasters
(LBC are notorious for this) - they argue that they pay a lot for their licence, so OFCOM have a duty to find and disable the "freeloaders".

Complaints from members of the public
- particularly if the broadcast content is political or otherwise dodgy.

Monitoring sites
: There are plenty of these all over the country. Many are completely automated, use broadband receivers to scan the bands, and log anything that appears, and then uses multiple sites to locate the source.

Patrols: The "authorities" send out patrols to known broadcasting sites, and they'll scan for "extra" stations, and then go and track them.

Finally: Stupid DJs. These are the clowns that brag to their mates about what they're doing, or carry around big boxes of records (or CDs), often straight to the studio. If they're well-known, they'll be followed, photographed, recorded off-air, and a dossier of "intelligence" will be gathered. Eventually, the station will be raided, and all the evidence compiled against the idiots will be presented in court. The fools that get prosecuted don't realise the lengths that the "authorities" will go to to curtail their activities, and the evidential dossiers are not ever presented in open court (and usually the clowns don't know of their existence)..... The Police see this as an "easy" prosecution, so are happy to provide resources - it's much easier than catching actual criminals!

If you think carefully about the above, you should be able to think of ways to avoid the knock on the door!

For example: One station I worked on used two transmitter sites, one higher power, and the other lower power. They were fed from a common link, and synchronised to the link signal. Because the two signals were (effectively) phase coherent, triangulation would find a location between the sites! "Capture Effect" ensured that the listeners' receivers would "hear" the strongest signal at their location, and this approach allowed this highly politicised, anti-government station to stay on the air for a long while. They had a number of pairs of sites set up, and would (effectively) relocate every day or two.... Expensive protection, but it kept them mostly safe until the government was overthrown!
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Re: Ofcom - How they trace location?

Post by piratefm » Sat Jul 09, 2022 2:23 pm

Albert H wrote: Sat Jul 09, 2022 1:49 pm There are several ways you'll be found:

Interference Reports
cause the "authorities" to come out and try to find its source.

Complaints from other broadcasters
(LBC are notorious for this) - they argue that they pay a lot for their licence, so OFCOM have a duty to find and disable the "freeloaders".

Complaints from members of the public
- particularly if the broadcast content is political or otherwise dodgy.

Monitoring sites
: There are plenty of these all over the country. Many are completely automated, use broadband receivers to scan the bands, and log anything that appears, and then uses multiple sites to locate the source.

Patrols: The "authorities" send out patrols to known broadcasting sites, and they'll scan for "extra" stations, and then go and track them.

Finally: Stupid DJs. These are the clowns that brag to their mates about what they're doing, or carry around big boxes of records (or CDs), often straight to the studio. If they're well-known, they'll be followed, photographed, recorded off-air, and a dossier of "intelligence" will be gathered. Eventually, the station will be raided, and all the evidence compiled against the idiots will be presented in court. The fools that get prosecuted don't realise the lengths that the "authorities" will go to to curtail their activities, and the evidential dossiers are not ever presented in open court (and usually the clowns don't know of their existence)..... The Police see this as an "easy" prosecution, so are happy to provide resources - it's much easier than catching actual criminals!

If you think carefully about the above, you should be able to think of ways to avoid the knock on the door!

For example: One station I worked on used two transmitter sites, one higher power, and the other lower power. They were fed from a common link, and synchronised to the link signal. Because the two signals were (effectively) phase coherent, triangulation would find a location between the sites! "Capture Effect" ensured that the listeners' receivers would "hear" the strongest signal at their location, and this approach allowed this highly politicised, anti-government station to stay on the air for a long while. They had a number of pairs of sites set up, and would (effectively) relocate every day or two.... Expensive protection, but it kept them mostly safe until the government was overthrown!
This is very interesting Albert!

Just done some online searching and came across some blurb on their Remote Monitoring Stations.

This is fascinating, the results from finding a pirate station in London.

https://www.ofcom.org.uk/__data/assets/ ... ams2_6.pdf

More reports here from 2005/6

https://www.ofcom.org.uk/research-and-d ... m-use/ams2

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Re: Ofcom - How they trace location?

Post by radionortheast » Mon Jul 11, 2022 9:26 am

Noone knows were they are, so noone can say if it would be picked up, they could listen in to the remote monitoring stations from baldock. I only know of one monitoring station that was taken down in Manchester, they problalby use something more discrete now, i’m always hearing of low power transmitters over there. If you were going to be paranoid, I guess they’d probably listen if there was an id, I think myself it could be hard to discern, with so many low power in car transmitters, also the fact the band is full of powerful legal transmitters they could easily block out a low powered transmitter, tropospheric and sporadic e signals can easily swamp a low powered fm signal, it would depend on the distance from the monitoring station.

Something to ask would be are there any pirates there have been in the past what happened to them?, are there any legal stations based there? . 5 watts is unlkely to cause interference, unless theres something wrong with the transmitter. Suppose pirates in tower blocks were higher power, which I suppose could knock out tv in the block or interfere with the licenced station, even once heard of someone phoning a station to complain about them been interfered with, back in the day you would have had people coming and going to studio, which probably would of been seen as suspicious, maybe the care taker/coucil/phone company or member of the public would spot the transmitter, they were always something to be got rid of. I guess it might be just down if someone notices the signal?

I do know of someone not directly who was in a city they left their transmitter going 24/7 for a year relaying a station, it was only few watts on a clear frequency, unlikely to interfere, their aerial not visible. Afew people were talking about it online, think it was someone that liked the station who was inquiring that got him found out. Its the first time i’ve heard of something transmitting from home on a few watts who got caught. It always used to be if you transmit on a clear frequency and don’t interfere your left alone, but maybe its just if noone knows about it. There was FIP in brighton that survived for 10 years 24/7

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Re: Ofcom - How they trace location?

Post by Albert H » Tue Jul 12, 2022 3:45 am

There are lots of small stations that stay on the air for years because they don't cause interference, and nobody really notices them.

The obverse of that is a friend of mine who moved into a new flat, and a few days after moving in, he set up a basic workshop to build a few rigs for his station. This was back in the 80s, when most stuff was built without PCBs, often using "lands" of cut-up PCB material Superglued to an earth plane (usually a piece of plain, un-etched PCB material. He was building an exciter, and had built the oscillator, buffer and two doubler stages to get up to the output frequency. It was probably 80 - 100 mW at this point, and loaded by a resistor. He'd been working on it for about half an hour when there was a banging at his front door....

There were two Policemen and a neighbour from about six flats away on the same floor. It turned out that his neighbour worked for the RIS!!! Talk about unlucky!
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Re: Ofcom - How they trace location?

Post by fmuser877 » Tue Jul 12, 2022 9:18 am

you might want to watch this but its about an AM station https://www.youtube.com/playlist?list=P ... r6RI3nyzG7

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Re: Ofcom - How they trace location?

Post by sinus trouble » Wed Jul 13, 2022 12:05 am

Tracking a Station is not really too difficult!

An amateur could easily track you down using something as basic as a 'Pocket radio'

Ofcom have experienced severe cuts to their budget over recent years! I would suspect you are more likely to get raided by your Landlord than Ofcom! :lol:

As long as your coverage is low? You wont attract much attention!

However, there are other threats to take into consideration? There are some nasty individuals that may be out to get you too!

If you are Broadcasting from your place of living? Do you really want to attract those characters to your Home??
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Re: Ofcom - How they trace location?

Post by piratefm » Wed Jul 13, 2022 7:20 am

Well. I think I may just have found their locations!

https://www.lars.co.uk/case-studies/str ... -upgrades/

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Re: Ofcom - How they trace location?

Post by piratefm » Wed Jul 13, 2022 9:09 am

piratefm wrote: Wed Jul 13, 2022 7:20 am Well. I think I may just have found their locations!

https://www.lars.co.uk/case-studies/str ... -upgrades/
Think this is one of their masts....

https://ibb.co/ryrnJWV

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Re: Ofcom - How they trace location?

Post by jvok » Wed Jul 13, 2022 2:14 pm

piratefm wrote: Wed Jul 13, 2022 9:09 am
piratefm wrote: Wed Jul 13, 2022 7:20 am Well. I think I may just have found their locations!

https://www.lars.co.uk/case-studies/str ... -upgrades/
Think this is one of their masts....

https://ibb.co/ryrnJWV
The tower at the back looks like one of the monitoring towers from the LARS link. The one at the front looks like air traffic control judging by the aerials. The bigger dipoles at the top look like civilian VHF air band, the smaller ground planes lower down look military uhf air band.

What I don't get is how can they DF pirates on FM with only 6 sites across the country, when the range of even a powerful rig is only 60 miles to the horizon? Unless they have other sites and those 6 are just the ones LARS worked on?

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Re: Ofcom - How they trace location?

Post by piratefm » Wed Jul 13, 2022 5:46 pm

jvok wrote: Wed Jul 13, 2022 2:14 pm
piratefm wrote: Wed Jul 13, 2022 9:09 am
piratefm wrote: Wed Jul 13, 2022 7:20 am Well. I think I may just have found their locations!

https://www.lars.co.uk/case-studies/str ... -upgrades/
Think this is one of their masts....

https://ibb.co/ryrnJWV
The tower at the back looks like one of the monitoring towers from the LARS link. The one at the front looks like air traffic control judging by the aerials. The bigger dipoles at the top look like civilian VHF air band, the smaller ground planes lower down look military uhf air band.

What I don't get is how can they DF pirates on FM with only 6 sites across the country, when the range of even a powerful rig is only 60 miles to the horizon? Unless they have other sites and those 6 are just the ones LARS worked on?
I would think there has got to be more than 6, I'm guessing the sites mentioned are just the ones you say they worked on. There must be a few monitoring stations in and around London for sure! Or maybe this is all there is outside of London. Who knows...I'd love to know where they are hahah.

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Re: Ofcom - How they trace location?

Post by BriansBrain » Thu Jul 14, 2022 1:32 pm

Found this on a facebook Page :whistle

Ofcom Tracking vehicle fitted out with Doppler tracking system.
Ofcom.jpg
:shock:
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Re: Ofcom - How they trace location?

Post by Steve » Thu Jul 14, 2022 3:35 pm

It'd be bloody funny if a pirate got up one of those masts and put a rig on it. :lol: :whistle

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Ofcom - How they trace location?

Post by Maximus » Tue Jul 19, 2022 1:55 pm

Check this out. It’s a serious piece of equipment and they pinpoint the location of a pirate.




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Re: Ofcom - How they trace location?

Post by piratefm » Tue Jul 19, 2022 4:58 pm

Maximus wrote: Tue Jul 19, 2022 1:55 pm Check this out. It’s a serious piece of equipment and they pinpoint the location of a pirate.




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:o very cleaver bit of kit that! Question is, how many of the pirate stations in London for example get raided/taken off air? With equipment like this I would have thought Ofcom would be out constantly taking them down..if it’s that simple?

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Re: Ofcom - How they trace location?

Post by sinus trouble » Wed Jul 20, 2022 2:12 am

Yes! Very clever stuff!

However, This is a marketing video on behalf of Keysight! Not evidence that Ofcom actually deploy this technology!

Pirate activity is not what it used to be! I suspect most pirates go under the radar at Ofcom due to their insignificance?

Finding a station is the easy part! Getting legal authority to bust that station is another matter!
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