2026LON Bonus: Analysis of Freeview DVB-T/T2 Free-to-Air Broadcasts in London

While in the previous sequence of posts, I covered my time seeing the various sights in and around London, this is a bonus installment which I had hoped to bring before my recent trip to Singapore, which was delayed due to an SSD failing on me.

Why only survey the sights and sounds of London on foot, when we can also do so by radio? As it turns out, I was travelling with my trusty TBS 5520SE multi-standard TV tuner, not simply because I was interested in seeing what free-to-air Freeview TV was like in the UK, but also because of my main mission. There was a slim chance we would be on TV (which, unfortunately did not eventuate) so we wanted to be sure we could capture it in full quality while I was there. Thankfully, the hotel I was staying at (Mowbray Court) had TVs in each room with an aerial cable that gave the true free-to-air signal, rather than some internal private TV distribution system.

So I ended up lugging home about 1.2TiB of transport stream recordings for analysis. Thanks to the hotel themselves presumably paying for a TV license, I didn’t have to worry about being caught by Ofcom or the detector vans either …

The Signals

Carefully removing the aerial lead from their TV and plugging it into my tuner, it seemed all the cables just barely reached. Thanks to Crazycat’s CrazyScan2, I was able to do some “crude” swept signal strength plots.

A full-band scan shows there is a cluster of “suspicious” signals right in the middle. Zooming into a smaller region of the spectrum and running an AirScan (blind-scan to lock services) …

… a total of six DVB-T multiplexes and …

… one DVB-T2 multiplex were found. Based on some poking around the UK’s Freeview website, it is predicted that I would have excellent coverage from the Crystal Palace transmitter 11km away.

Ofcom has more details about the transmitters across the country, but I found “going in blind” and doing a blind scan to be the fastest way to get going.

Per Carrier Monitoring

Let’s take a closer look at each carrier. All transmissions are made with 8MHz channel bandwidth.

The first at 482MHz managed to come in fair at 32dB SNR. It’s broadcast using DVB-T in 64QAM mode with 3/4 FEC and 1/32 guard interval and 8k FFT mode. This multiplex hence carries 27.150Mbit/s of data. This seems to be a fairly standard wide-area broadcast configuration.

The carrier at 490MHz was received at 33.5dB SNR and surprisingly, differs slightly on the configuration. While using the same DVB-T, 64QAM modulation 1/32 guard interval and 8k FFT mode, it uses a more robust 2/3 FEC rate. As a result, the payload capacity is slightly less at 24.880Mbit/s, but it is slightly more robust.

The carrier at 506MHz is a bit stronger, received at 34.25dB SNR, while using the same sort of modulation as the first.

The carrier at 514MHz is received with 33dB SNR and is modulated like the second carrier.

The one at 530MHz is received at 32.75dB SNR (all fairly similar) and has characteristics like the first carrier as well. It’s not unusual to see broadcasters who are sending multiple muxes from the same site to settle on similar modulation modes as they will all want similar coverage.

Here’s where we get to something new. In the UK, it seems all their HD services are carried on a separate DVB-T2 mux that older DVB-T tuners cannot receive. As a result, this mux uses a much denser modulation of 256QAM – a level I thought might be impractical but the constellation plot proves otherwise with the symbols mostly cleanly resolved. Even at 32.5dB SNR, it locked although I can’t be sure the BER remained at zero at all times. Using 2/3 FEC and a 1/128 guard interval with 32k FFT mode, the 8MHz channel can squeeze 40.220Mbit/s of payload rate. Absolutely wow! That’s almost an extra 50% as much as the DVB-T carriers and presumably with a similar level of coverage.

Finally, we get to the local television mux, which has to “slum” it with fewer broadcast sites and lower power. As a result, it chooses the most conservative QPSK modulation (the cleanest looking plot with four points, aside from the BPSK pilots), with an ordinary 3/4 FEC rate, 1/32 guard interval and 8k FFT mode. The payload rate is just 9.050Mbit/s, or just under what a DVD video disc at 1x could give you.

The Services

Having examined the signals, it is time to concern ourselves with what is on the multiplexes. For this, I examined the recorded files using TSReader to create my own summary tables. I only just found out that the creator of TSReader, Rod Hewitt KG6TTD (G6TTD), had passed away in March 2025. Graciously, development still continues, open-sourced on GitHub through a memorial build that has been modernised for contemporary build tools.

Regardless, I’d have to say I was not prepared for what I found. The UK Freeview service has a boatload of services, many more than I could imagine. Some operate as traditional 24/7 broadcast services, others are interactive text-only, others do time-sharing with other channels, while some are purely streaming but have a broadcast presence in terms of a PMT entry. Some channels are in “duplicate” across muxes and there is a lot of shopping TV that occupies both dedicated channels and the “off-hours” of the smaller channels. Aside from shopping, there also seems to be somewhat more nudity in the off-hours as well, in addition to sign-language interpreted versions of programs and time-shift channels. Most major channels have a second audio program PID allocated but only active on-demand. It’s a very different landscape to home, but most muxes are very crammed and statistical multiplexing appears to be used alongside careful bitrate optimisation for each service.

Summary Table

The full summary table, listed in order of frequency, is shown below:

For better readability, there is a PDF version here: lontv-summarytable-mar2026.pdf

There is also an alternative version listed by LCN (left) or by total service bitrate (right):

Downloadable PDF versions – lontv-summarytableLCN-mar2026.pdf,
lontv-summarytableBR-mar2026.pdf

A few interesting observations jump out at me. The first is that some services have anomalously low bitrates due to the time-sharing nature of their operation. They may have been in operation at the beginning of the observation period and finished soon after – the rate is averaged across the whole recording resulting in incorrectly low rates for ITV3+1 and Jewellery Maker.

There is a lot of use of “horizontally compressed” MPEG-2 formats to squeeze more channels into the same mux. The result is a picture that looks somewhat soft – 544 and 704 are used instead of the full 720. Likewise, secondary audio programs are usually in mono and at reduced bitrates. Interestingly, there is one channel (That’s TV 3) that’s running MPEG-4 encoding on a DVB-T mux – everything else sticks to traditional MPEG-2 video and MPEG-1 audio. Bitrates for MPEG-2 SD vision are in the 1-1.5Mbit/s range mostly, which MPEG-4 SD streams being given approximately half this. Bitrates for MPEG-4 HD vision are in the 3-4.5Mbit/s range. One channel (Channel 4 HD) even carries 5.1-channel AAC-LC audio, being the only non-mono/stereo service. Low-bitrate MPEG-4 audio uses HE-AAC, while higher-bitrate MPEG-4 audio remains AAC-LC.

While I thought the DVB-T2 mux was only carrying HD services, it is also carrying MPEG-4 AVC encoded SD services as well. I suppose it’s a fair bet that most DVB-T2-capable receivers would understand MPEG-4, but nothing technically stops the use of MPEG-4 on DVB-T muxes – just the possibility that older set top boxes may find services that they cannot display which could attract complaints.

PID Bitrates

For those who are interested, per-PID bitrates are given for each mux below – I can’t rule out the possibility of there being error packets in the counts. This was all recorded in March 2026, some in odd-hours of the day, as this was a bit of a side-project that happened while I was mostly asleep.

A downloadable PDF version for easier reading: lontv-pidbitrates-mar2026.pdf

Mux Utilisation

On the whole, most muxes were very well used – 482MHz and 514MHz are the standouts with under 2% of null packets. The 490MHz, 506MHz and 530MHz muxes are fairly full, but so is 586MHz because of its considerably lower payload bitrate. In fact, the highest-rate DVB-T2 mux carrying HD services has the most null packets of all.

In terms of absolute bitrate, it seems that 490MHz, 506MHz and 530MHz could all carry one more MPEG-2 SD service, at least in theory. The 546MHz mux could possibly carry two more MPEG-4 HD services with that much room – in fact, it’s null capacity is probably enough to carry all of the LTVmux in its entirety.

Idents

I guess the best way to prove the reception would be to catalog the station logos (where available) or a frame grab from the running service that has a reference to its name. I note that there didn’t seem to be variations of logos for time-shifted services, so I had to omit those. Click on thumbnails for full-size.

482MHz

490MHz

506MHz

514MHz

540MHz

546MHz

586MHz

Conclusion

Looking around Freeview in London was quite eye-opening. Never did I think that free-to-air (albeit, supported by both TV-licenses for public service and advertising for commercial services) would have so many channels to choose from, nor the high level of streaming and interactive service integration (including adult services). Secondary audio program capability seems common amongst the major channels, with lower bitrate mono options frequently chosen. For the most part, interactive and internet-connected features are very finnicky to get working at feature parity across different set-top boxes and TVs, especially older ones but it’s nice to see it being deployed in practice. The presence of time-shared, non-24/7 channels is quite different to what happens at home in Australia, where stations generally run around-the-clock.

Despite the healthy 7 x 8MHz bandwidth dedicated to broadcast, the high level of channels and legacy DVB-T MPEG-1/2 baggage means that bitrates are squeezed and picture quality takes a noticeable hit. One way they’ve squeezed things is to use horizontally-compressed 544- and 704-pixel formats instead of the traditional 720-pixel format. The use of DVB-T2 to carry high-definition does result in noticeably higher payload capacity for that mux, my first experience receiving 256QAM “in the wild” which was more successful than I had imagined. While there is some spare bandwidth on that mux, it seems that high-definition vision PIDs are still in the 3-4.5Mbit/s bracket while using MPEG-4 AVC High@L4 encoding, albeit with full 1920x1080i resolution.

The large number of services made the analysis somewhat challenging and the presence of time-shared services means some services may register anomalously-low bitrates as their partial broadcast bits are averaged over the whole monitoring period to determine the average bitrate. While we didn’t end up on the TV, I can definitely say it was a worthwhile venture to have bought along my TV tuner for this trip. After all, who knows how much longer broadcast TV will be around for …