First Look: Sat-Comm Karbon 75 Ka-Band Flyaway Antenna
As regular readers know, I often cover backhaul and contribution feed technologies for Streaming Media. With my own passion for and experience in live webcast and live signal streaming, I keep a close eye on the options available to readers at both the major broadcaster and independent journalist/school football webcast ends of the spectrum.
We have, over the past few years, looked at technologies such as leased lines, domestic ADSL, traditional TV satellite news gathering, facility lines, bonded ISDN, VSAT IP Satellite, and of course more recently the emerging kit and services offering cellular multiplexer (cellmux) channel bonding and link-aggregation.
To be honest, all of these should optimally be in your tool kit as a webcast producer or live TV/radio streaming engineer, and I refuse to be drawn into an argument about which is best. Each has its own strengths and weaknesses, and it is absolutely critical that you have a rich awareness of these capabilities, but remain focused on the business problem you are trying to solve. Naturally you will find one will perform well in one situation, where in another it will fail dismally.
While these days I design systems for a large number of different clients, and this gives me scope to recommend different technologies on a client to client basis, I also appreciate that if you are reading these pages looking for advice as you choose technology so you can build an operating webcast platform that will suit a variety of circumstances you may encounter, you simply may not have the budget to invest in all of these technology options, and you will have to select perhaps just one or, ideally, maybe two that give you a suitable workflow for your business.
A Backhaul/Contribution Feed Primer
Let us just recap the requirements of a backhaul or contribution feed. Incidentally these terms mean exactly the same thing, but the choice of words will vary with which end of the link you are on: If you are onsite at the event sending the signal into your distribution network, then you would usually think of the link as a contribution feed. Conversely if you are focused on the distribution headend servers receiving the inbound feed from remote engineers at the event, then you would normally call the link the backhaul (and backhaul is also the name used by mobile operators for the signal path from a transmitter tower to their core network, and for similar reasons).
Backhaul/contribution feeds in live streaming are one of the most important links to get right: If you have a poor service on this link into the distribution network, then the only thing the distribution network can send out is a poor service to all audience members.
With some of the technologies I mentioned above (leased line, traditional TV satellite newsgathering, and facility line) the connections are expensive and dedicated to the purpose, and accordingly will come with a high Quality of Service and are extremely reliable.
The facility line and leased line services are installed many weeks or months in advance, tested extensively, and contracted for an entire year (or multiple years). For a TV station this is a great option, but for a small one-day webcast a facility line is almost always prohibitively expensive. There are a few locations where a service like this may be installed for regular use—for example there is a facility line in Leicester Square in London which is regularly used for TV broadcasts of the red carpet at film premieres. Such public locations with frequent valuable content justifying installing a costly permanent line are rare. For the webcaster with (typically) sub-prime content, facility lines on site and leased lines are prohibitively expensive for one of events.
Because outside broadcast is a well-established workflow in the TV broadcast industry, an option may be to hire a TV satellite truck for a one-day event. This will provide a dedicated ‘TV broadcast quality’ signal path and allow the delivery of the signal to an infrastructure where a downlink and encode provider can acquire the TV signal at the satellite downlink, and then, using a streaming encoder, they can convert this to a live webcast stream. The permanent location of the streaming encoder in this model means that leased lines with high-quality SLA can be installed between the encoders and the CDN/distribution network entry points, and reused from event to event, while the truck does the moving around with the tried and tested outside broadcast technology. This model works well for many of the medium and larger streaming companies because of the constant reuse of the core services and, at scale, the relative cost of the day hire for the satellite truck is valued against the reliability of this age old technology and the simplicity of the setup. Obviously this is a logical workflow if the event already has TV coverage and the webcast is a ‘simulcast’ online of the same broadcast feed.
To bring this into perspective though, a leased line may cost in the range of £500 per month (on a 12 month or longer contract) where recently I booked a satellite truck from an event in Rio which cost about $10,000 for the day including the bandwidth, operators, and site survey, plus a further $2,000 for the downlink and encode to a streaming format in London. Had the venue already had a leased line in place then we could have sent a guy with an encoder to the event in the place of the satellite truck, and they would have encoded and contributed the feed directly to the distribution network over the leased line from Rio—and this would have been significantly cheaper (approximately $1,500 for personnel on top of the leased line install costs of about $6,000). Obviously, had the leased line been already available in the venue (perhaps installed by the venue to attract more webcasts!) then the overall cost would have been $1,500 for the manpower or thereabouts.
Find Your “Good Enough” Point
As you can see, the high Quality of Service options are available. It’s just that your event potentially needs to have a financial return of at least $12,000 forecast to cover a satellite TV outside broadcast truck on site for a day.
So what are the options for those projects on a tighter budget? Well the first, and most important, question to ask as one starts to try to compromise quality for budget is ‘when is good enough good enough?’
While it obviously excites any content publisher to proudly announce that their content will be available in a super-mega-ultra-high-definition-low-latency-cross-platform form, the fact is that setting the highest quality possible as a “requirement” is folly. It is purely branding for the sake of branding.
What the audience actually wants (without exception in my experience) is an engaging immersive and enjoyable experience that “just works,” and those webcasters who sell on pixel resolution and highest possible bandwidth frankly miss the point.
I have lost count of the number of webcasts I have seen that are produced at a bitrate that my Wi-Fi cannot keep up with, or with such high pixel density that the decoder on my laptop burns a hole in the laptop battery and it’s dead before the show is over.
Working to lowest common denominator as a first principle is a must. And yet it is often the last consideration (typically prompted by audience feedback that the stream is not playing well). Think about your audience—are you really only interested in those with high-end machines and who live in central urban metro-zones and are serviced with Gigabit fiber? Perhaps if you are an IPTV operator this makes sense, but if you are trying to stream a small live concert to a globally diverse audience with fans all over the world, it may make more sense to simply provide an audio/internet radio stream and drop aspiration of video altogether. Those listeners in Africa or New Zealand may then actually be able to tune in on their 3G dongle in the outback.
For sure, once you’ve got this lowest common denominator is in place, then add layers of higher-quality experience options such as higher adaptive bitrates for those whose bandwidth can handle them, but rather than trying to promote the highest possible quality to that tiny premium audience, instead focus on providing a great service for everyone, and then add the premium high-end services as a bonus.
Many companies do HD badly. Very few do “LD” (low definition) well these days, since they are so focused on trumping the competition by offering higher and higher pixel density and bitrate to their customers as a “must have.”
Once you work out where your “good enough” point is then you can properly scale your contribution/backhaul architecture.
Don’t forget that for some events, such as small internal presentations in a business, a domestic DSL line with 256Kbps may well be more than adequate—the audience will sympathize even if the neighbor contending with you for the available 256Kbps and reducing your signal quality compromises the line speed. Indeed 256Kbps on a domestic DSL is more than likely considerably over-provisioned for a live radio contribution, be that to internet radio or even sending a contribution over DSL to a traditional broadcast radio station.
The Cellmux Alternative
The range of cellmux technologies attempting to use the cellular for backhaul has proliferated in the past 3 years. While a single 3G service neither offers enough bandwidth nor enough stability for a broadcast, by aggregating many such services together and treating them as a single “bonded” pipe, this type of “over-provisioning” is enabling broadcasters to get away with using cellular networks (which offer little or no Quality of Service guarantee) to provide high bitrate streaming contribution feeds. As regular readers will know, I have found this method attractive and highly disruptive to the models we have discussed above. The kit is falling in price, the flexibility is a very strong value proposition and this is all adding up to being a game changer: We are seeing live feeds from moving vehicles, and from more and more previously inaccessible locations.
Cellmuxes have been absolutely critical to opening new media paths from ever-more-challenging live locations, and through this have created new content opportunities.
But it is important not to drink all the Kool-Aid: Cellmux works so long as the people nearby to the cellumux don’t start hammering their smart phones’ data services during the broadcast; the cellular network operators do not differentiate the traffic between a twitter user on an iPhone and a cellmux-based broadcaster at the finishing line of the Olympic race, and while they augment live broadcast well, basing your entire premium broadcast on this technology is foolhardy.
In the context of a pre-planned premium online webcast from a static location, cellmux is a great backup for resilience, but there are better options at similar prices that can provide guaranteed Quality of Service that cellmux cannot. I recently covered Eutelsat’s Ka-band-based KA-SAT Newsspotter service in a separate article, and as far as connectivity is concerned this emerging option is extremely exciting for the webcaster.
For a few tens of pounds/dollars an hour one can ad-hoc provision a 10Mbps high quality IP connection from anywhere that can “see” the satellite. Obviously cellmux can work on moving vehicles and in places where line-of-sight to the satellite may not be possible, and in that domain cellmux is the clear leader, however these new IP via satellite services represent the same Quality of Service as TV satellite uplinks, but are much smaller—essentially portable by one person—and much cheaper by the hour.
The Sat-Comm VSAT System
Last week I was lucky enough to have a Sat-Comm Ka-band flyaway/portable Very Small Aperture Terminal (VSAT) system brought to me to test out, prior to me commissioning them for two or three series of sporting events I am overseeing from a streaming perspective.
The requirements for these events include these characteristics:
- The events are all from different locations, changing from day to day as they “tour,” so mobility is key.
- The events require a 350Kbps low-bitrate and a 1Mbps high-bitrate contribution feed and sufficient bandwidth to monitor the output feed back onsite at the event.
- The event’s video producers want to be able to establish the connectivity themselves to keep the manpower costs down, and this needs to be a “quick job.”
- They want to be able to encode onsite so that they have flexibility to stream live to their website even when the events are not available live on TV.
Now, cellmux could have been a contender, but some of these events are pay per view, and so the risk of introducing links that may simply fail mid-broadcast was a major risk, and one that leaves cellmux in the wings.
The NewsSpotter service is only available in Europe, and for two of these clients, all their audiences are in Europe. For the third client it emerged that for those events not in Europe we have TV broadcast satellite up link coverage, and we will downlink and encode those in London anyway. For the rest of the events we are looking to use NewsSpotter and to connect to the NewsSpotter service live we are going to deploy Sat-Comm’s flyaway terminals.
Sat-Comm is a satellite terminal manufacturer and integrator based in the UK that has introduced the 75KA Flyaway dish (see pictures). The whole system packs into an aircraft-ready hold bag and weighs around 23kg.
Now while that is massive compared to the average cellmux (which is often only slightly larger than a cigarette pack), it also comes with a 10Mbps uncontended service proposition that is available from Turkey to Spain and from Libya to Norway. That is something that no cellmux can offer.
The flyaway we tested was unpacked and put together, leveled with its neat (and purportedly unique) gimbal system, elevated (using data from an iPhone app that helps with all the positioning) and locked onto the satellite with a quick manual twist (guided with a tone)—all in the space of about 10 to 15 minutes.
I recall occasions attempting to point dishes like this manually with meters and compasses, and spending several hours doing so. This new setup seemed simple and quick. This changes the dynamic significantly. It becomes easy to create a live link in moments from anywhere with a clear view of the sky. 10Mbps is a flexible amount of data pipe—whether for the super-mega-HD bitrate or for a mix of lower bitrates and formats, it should get most live streams live. Indeed once the system had a lock on, the booking process for bandwidth was “self-service” requiring the operator to simply fire up the system from the next 15-minute slot by booking online.
The terminal costs about £12,000—so in the cost of two TV broadcast truck event-hires you could purchase this terminal outright—and this means that if you have a series of events you could quickly be in a profitable situation, even including the bandwidth.
Once you have a terminal like this in your control you are online, with a service level guarantee whenever you want, and since you can encode and send a stream directly to the CDN, the only other cost is the CDN cost and man power. In other words, this represents an incredibly versatile solution.
Like all the other solutions for backhaul and contribution, there are different situations where VSAT has its applicability and others where it simply won’t work.
However as a broad rule of thumb it does appear that a Ka-Sat Sat-Comm terminal backed up by a cellmux could provide a great option for todays live webcaster.
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