Outside Broadcast Connectivity: What an OB Truck Needs From Cellular

One 1080p contribution feed needs 6 to 12 Mbit/s of sustained upload. An OB truck at a full venue sends far more than one. Remote cameras in the paddock or the fan zone, ISO feeds, a return feed and talkback to a studio hundreds of kilometres away, timing data for graphics and twenty crew laptops all leave the truck at once. The satellite uplink or venue fibre is often booked for the main programme feed, so the cellular side of the truck carries everything else. On many trucks, that cellular side is still designed as an afterthought, and it shows the moment the venue fills up.

Outside broadcast has moved a large part of its traffic onto IP, and much of that IP traffic leaves the truck over mobile networks. This article looks at the OB truck as a connectivity system: which functions need a connection, how much bandwidth each one takes, what bonded cellular can carry, and how to build the antennas, modems and SIM strategy so the truck performs at a full venue. For the commercial side, see our broadcast connectivity solutions.

What is outside broadcast connectivity?

Outside broadcast connectivity is the set of network connections an OB truck or OB van uses to send live video and audio from a remote location to a studio or master control, receive return feeds and communication, and support remote production, file transfer and crew access, delivered over fibre, satellite, cellular or a combination.

Cellular has three roles in this mix. For small productions and news, bonded cellular is often the primary contribution path. For large productions with fibre or satellite, cellular carries the extra feeds, the comms and the backup. And for every truck, cellular is the fastest way to get online on arrival, before any other circuit is ready.

The connectivity functions of an OB truck

An OB truck needs several connections because it does several things at once. Each function has its own bandwidth, direction and tolerance for delay.

The table makes the main point clear: most of the critical traffic is upload. A connection that looks fast on a download speed test can still fail the truck.

Upload is the constraint

Consumer mobile networks are built for people who download, and most 4G connections offer far less upload than download. At a venue full of spectators, the upload capacity of each cell is shared with thousands of phones sending photos and video at the same moments the production is live.

A 1080p contribution feed in H.264 needs 6 to 12 Mbit/s of sustained upload. With the recommended buffer of 35 to 40 percent for variation in the network, that means roughly 8 to 17 Mbit/s of real upload capacity from the cellular side, for one feed. Add a second camera, file transfers and comms, and the requirement multiplies. Why symmetric capacity matters so much for broadcast is explained in our article on symmetric vs asymmetric upload.

Built for upload: Weconnect’s symmetric profiles

Weconnect designs its broadcast connectivity for the direction an OB truck actually uses. Symmetric speed means upload and download run at the same rate: a 100 Mbit link is 100 down and 100 up, where most consumer or shared mobile connections deliver something like 100 down and 10 up. Broadcast crews send contribution feeds, bonded encoders push several streams at once and remote production sends camera signals back to a central gallery, so the profiles treat uplink as a first-class direction. Routing is fixed, the APN is dedicated, and there is no shaping or fair-use throttle that quietly drops the upload after a few hundred gigabytes. What is provisioned on day one is what the truck gets in month twelve, in both directions, at every venue on the calendar.

Bonded cellular in and around the OB truck

Bonded cellular combines several mobile connections into one logical link. The encoder or bonding router spreads the data over all modems, and a server at the receiving end reassembles the stream. When one connection slows down, the others take more of the load. For an OB truck, bonding is used in three places:

• Portable encoders on camera or in backpacks, sending feeds from positions where no cable reaches.
• Rack-mounted bonding units in the truck, carrying contribution or extra feeds from the truck itself.
• Bonding routers that give the truck a general-purpose IP connection for comms, data and crew.

Bonding increases capacity and resilience within the limits of the networks at the venue. In real conditions, bonding efficiency is typically 15 to 25 percent below the theoretical sum of all modems. The trade-offs between bonded cellular and satellite for the main feed are covered in our article on bonded cellular vs satellite.

The protocol on top of the connection matters too. SRT and RIST recover lost packets and handle jitter, and they need headroom and a stable latency budget to do that well. What these protocols ask from the connection is explained in our article on SRT and RIST.

SIM strategy: spread the bond across operators

Bonding over four modems on one operator still depends on one operator’s masts, one core network and one congestion pattern. When that operator’s cell at the venue fills up, all four modems slow down together. That is why broadcasters use SIMs from several different operators in one encoder, an approach explained in our article on multi-carrier SIMs in one encoder.

For a truck that works across Europe, managing a local SIM per operator per country is a logistics problem. Non-steered multi-network SIMs solve it: each SIM connects to the strongest available network in the country where the truck is parked, free to choose among all partner networks. Weconnect SIMs have access to 700+ networks in 195 countries, with multiple operators per country. They support permanent roaming by default, as part of how the service is designed and contracted, so a truck that spends a whole season on the road abroad keeps the same SIMs without any technical intervention. In a bonding set-up, the modems can be spread across different networks so the bond keeps its diversity at every venue, from a stadium in Germany to a rally stage in Spain.

Data volume is the other half of the SIM strategy. A single 1080p feed at 10 Mbit/s uses about 4.5 GB per hour. A production day with several feeds, file transfers and rehearsals quickly reaches hundreds of gigabytes. Weconnect profiles carry no shaping or fair-use throttle on the uplink, so the capacity available at the first rehearsal is still there in the final minutes of the live show. Data pooling spreads one allowance across all SIMs in a truck or fleet, and pay-as-you-go models for event-based broadcasting keep costs tied to the days the truck is actually working. Plans can also be combined for redundancy, for example pay-as-you-go SIMs in the bonding encoders plus a high-volume SIM in the truck’s general router.

Antennas and installation on the truck

The modem inside a steel truck body receives a fraction of the signal available on the roof. Cellular performance of an OB truck therefore starts with the physical installation:

• External antennas on the roof or a mast. Height and a clear line to the masts make the biggest difference, especially in stadiums where the truck is parked in a compound between buildings.
• Separate antennas per modem. Give every modem its own antenna with enough spacing, so the bond keeps its full benefit.
• Short, good-quality cables. Every metre of cable between modem and antenna costs signal. Mount modems close to the antennas where possible.
• Access for portable units. Portable encoders need space to be placed outside the truck when the signal inside the compound is weak.
• Site survey before the event. Measure upload per operator at the planned truck position, ideally at a comparable event, since an empty venue gives a misleading result.

Backup: keep the paths independent

A truck with fibre, satellite and bonded cellular has three independent paths when none of them share a single point of failure. Common shared weak points are the same power circuit, the same router and the same operator on the backup SIMs as on the main bond. The design rules for independent backup paths, including switchover and testing, are covered in detail in our article on redundancy and backup connectivity for OB vans.

OB van internet for the crew and production office

The crew needs internet too: email, rundowns in the cloud, social media teams uploading clips, and production staff joining calls. Mixing that traffic with the contribution feed is a classic mistake. Give crew and office traffic its own connection, or at least its own network with a bandwidth limit, so the live feed keeps its capacity when someone starts a large download. At large events, the production office often sits outside the truck, and its connection becomes part of the wider event network, as described in our article on event WiFi.

Managing SIMs across trucks and productions

A facilities company with several trucks, flypacks and portable encoders runs dozens or hundreds of SIMs that move from production to production. Through the Weconnect connectivity management platform, every SIM is visible with its usage and status. SIMs can be activated when equipment ships and suspended when it returns, usage alerts flag a unit that is consuming far more than expected, and cost places split connectivity per production or client, so it can be recharged correctly. After each production, the usage data shows which operators performed best at which venue, which helps plan the next visit.

Checklist: preparing the cellular side of an OB truck

1. List the functions. Contribution, extra feeds, return, comms, REMI, file transfer, crew.
2. Calculate upload per function. Include a buffer of 35 to 40 percent for contribution feeds.
3. Survey the venue. Upload per operator at the truck position, preferably during a comparable event.
4. Spread the SIMs. Multi-network SIMs with symmetric, upload-first profiles across modems, so the bond uses several operators.
5. Check the installation. Antenna height, separation, cable length and access for portable units.
6. Separate the traffic. Crew and office on their own network, with limits.
7. Test the backup. Disconnect the primary path during rehearsal and confirm the switchover.

Veelgestelde vragen

What is an OB truck?

An OB truck, or outside broadcast truck, is a mobile production facility that contains the equipment to produce live television from a remote location, including vision and sound mixing, replay and graphics. It sends the finished programme or individual feeds to a studio or master control over fibre, satellite or bonded cellular.

How does an OB van connect to the internet?

An OB van connects through a combination of paths: fibre where the venue provides it, satellite for booked contribution, and bonded cellular routers and encoders that combine several mobile connections. Cellular is also used for comms, file transfer, data feeds and crew internet.

Is bonded cellular good enough for outside broadcast?

For news, smaller productions and extra feeds, bonded cellular is widely used as the main contribution path. For large productions, it typically complements fibre or satellite as an extra or backup path. Performance depends on upload capacity at the venue, the number of operators used, the antenna installation and SIM profiles built for symmetric upload.

How much upload does an outside broadcast feed need?

A 1080p contribution feed in H.264 needs about 6 to 12 Mbit/s of sustained upload. With a buffer of 35 to 40 percent for network variation, plan for roughly 8 to 17 Mbit/s of real upload capacity per feed, plus capacity for comms, return feeds and file transfers.

Why do broadcasters use SIMs from different operators?

Modems on the same operator share the same masts and slow down together when that operator’s network is congested. Spreading the SIMs across several operators keeps the bond working when one network fills up, which is common at full venues.

How much data does an OB truck use?

A single 1080p feed at 10 Mbit/s uses about 4.5 GB per hour. With several feeds, rehearsals and file transfers, a production day can reach hundreds of gigabytes, so live work calls for data plans with full uplink capacity from the first to the last gigabyte, with no shaping or fair-use throttle.

Volgende stappen

Weconnect supplies multi-network SIMs with symmetric, upload-first profiles for bonding encoders, OB trucks and flypacks, with access to 700+ networks in 195 countries and central management across productions. Whether you run one truck or a fleet of facilities across Europe, we help you build the cellular side that holds up when the venue is full. More on our approach is on our page for mobiele connectiviteit voor uitzendingen and our broadcast connectivity solutions. Challenge us with your connectivity requirements. Direct reactie binnen 4 werkuren.