Digital Switch Over was recently completed at the Winter Hill transmitter - arguably the first site serving a large urban area to do so. The city of Manchester is home to a diverse range of PMSE users, including large TV studios, numerous concert venues & theatres, sports venues, and all number of community users; all sitting in Winter Hill's coverage area.
As the analogue signals in area were being switched off, myself & Principle Engineer Simon Eley visited the city in JFMG's survey vehicle. We were able to conduct signal measurements in and around some of the key venues in the area to help us better understand the availabilty of spectrum in Manchester. And a trip west along the M62 allowed us to do more of the same on Merseyside.
Now DSO has completed, the six analogue services serving the city have closed whilst the digital services have moved frequency and gone up in power. These changes have been fully refelected on the UHF Mic Location Planner on JFMG's Web Site. As a result users of microphone frequencies above 742 MHz will notice improved availability of useable spectrum in this range in and around the city.
A wet & windy winter doesn't mean I've retreated to the comfort of Alfred Place. I recently joined one of our customers on location, where they were filming a popular weekly TV show. There had been some on-site problems with wireless microphone performance, and I offered to help out by investigating as to whether the issue was spectrum related. With the studio nestled amongst small industrial premises, there was scope for all manner of electrical noise in the area.
I was able to check there were no signals from external sources, such as local TV transmitters, unlicensed users, arc welders ( ! ) etc, - as well as other equipment on the set. Using one of our RF Analysers I could look across a range of mic frequencies - and in time domain too. This device would show up short bursts of interfering signals and even glitches in the mic signal.
It is so sensitive that it could detect one of the microphone frequencies after a presenter had left the set for a crafty ciggy break. The mic receiver rack had muted, my spectrum display had fallen into the noise, but a thin line remained on the screen’s waterfall display – it’s the second line from the left of the display in the picture below.
At the end of the visit I was confident the spectrum at the location was clean. The earlier problems haven’t re-occurred, and filming has continued since unhindered – so the problem has been attributed to a rogue event. However, it was, as always, great to meet some of our end users on the ground and provide some support during their busy schedule. My only regret was, me being so organised, I’d packed some sandwiches, so had to decline the offer of some legendary location catering. Maybe next time.
NFL In London. A football game at Wembley, nothing new there you’d think. But, on 25th October this year, and for the third year running, the National Stadium played host to the National Football League for the American version of the beautiful game. And this was for no mere demonstration game. The Tampa Bay Buccaneers were the home side to the New England Patriots for a regular season game in the NFL’s 2009 season.
As well as a sporting event, this was to be a big wireless event. Demands for spectrum came from domestic and US television & radio, sound specialists, a film crew making a documentary about the event, and there was a significant requirement from the NFL themselves.
The NFL requirement may seem surprising; but radio communications are used by the teams as well as the referee & game officials. No longer are plays passed from the sideline to the quarterback by a team member running to and fro. The coach on the side line relays the play over an encrypted radio to the quarterback’s in-helmet receiver. Oh, and to stop the coach from cheating, by directing the quarterback real-time, NFL officials cut the radio link once the ball is in play.
Initial Work. Back in mid-July JFMG engaged with the Manager of NFL Frequency Organization Group, and the Group’s Chief Coordinator. In effect the NFL has its very own JFMG looking after all of the games played every year in the USA. In fact there’s a ‘Game Day Coordinator’ or GDC assigned to each team. The NFL guys knew which organisations from the USA were likely to be bringing wireless equipment to the game. They circulated information detailing licensing requirements in the UK, and directed the American organisations towards JFMG.
From mid-August applications started to arrive. As a ‘Major Event’ frequencies were not assigned first-come first-served, as soon as they were received. Instead requests were held until the overall demand was clear; and I took the overall responsibility of coordinating and issuing all licenses for the event. Whilst our established UK licensees were familiar with our process, for many of the US users this was their first foray this side of the pond. A few trans-Atlantic phone calls helped me understand their exact requirements, and some technical aspects such as the all-important tuning range.
Coordination. In the talk-back bands I had to fit in a number of outside broadcast customers plus the NFL. The NFL’s helmet radios were crystal controlled. Hard to believe in this digitally synthesised age. But these devices need to be small, light & robust; and be waterproof. It’s hot and sweaty in those helmets. Thus the receivers are encapsulated meaning they couldn’t be frequency shifted. Thus I had to fit the OB users around these fixed frequencies and maintain a plan free from intermodulation. Fortunately one of the OB crews was able to retune their base stations, allowing me to spread usage and keep spectrum clean.
In-band, there was a need to find over 100 frequencies that could co-exist with one another and be kept away from the high-power television broadcasts coming from Crystal Palace. Fortunately, equipment differences meant the applications from the USA were for areas of spectrum not usually occupied by UK users, reducing congestion.
With barely a week to go before the game, final applications were received and the last of the licenses issued. Pressure off?? No chance. Now my attention turned to on-site activities at the event itself. All zones accreditation was provided by the NFL, who, as with all games had their own Game Day Coordinators on-site. Ordinarily, the GDC's would come over from each team, but on this occasion it was the Manager & Chief Coordinator of the NFL Frequency Organization Group instead.
On-Site. Saturday was set up day, with most of the radio frequency users busy assembling and testing their equipment. I was able to visit a number of the crews from the OB and sound companies. I also met with Wembley IT staff, who were responsible for the stadium’s in-house radio communications facilities, and are keen to ensure visitor’s systems can co-exist with theirs.
Touring the technical areas I was also able to ensure compliance to frequency plans, and take a look at some of the antenna installations.
On Sunday, match day, there was activity on site from around 9 am, despite kick-off being some 8 hrs away. Almost immediately I found an uncoordinated (and thus unlicensed) frequency being used. This was simply down to a programming error on a radio mic, and the ‘offender’ (who shall remain nameless!) was quickly found and encouraged to retune to their correct frequency.
My approach in these instances tends to be the ‘carrot’–coordination is in the interest of all spectrum users in ensuring the event passes without spectrum problems. The NFL Coordinators have a “stick” - a low tolerance policy towards uncoordinated radio frequency use at their games. Penalties include eviction from the game and confiscation of equipment (see below). They have security guys the size of some of the players, and, I am told, have evicted NFL staff from their own events. I’m not even remotely jealous of their powers; honestly.
Game-time. As the match got closer there was concern over interference to the microphones being used for the National Anthems, with so many coordinated users moving around the touchline. The risk was small but real; so as Toni Braxton started belting out the Star Spangled Banner, I found myself by Wembley’s hallowed turf, spectrum analyser in hand, adjacent to the microphone receive point. The aim was to provide a ‘cordon sanitaire’ around the antennas. And to move any users who encroached the antennas during this time - in the event this wasn’t necessary.
Anthems over, game time. Working with the NFL Coordinators, we kept an eye on all spectrum use, with attention given to the coach – quarterback frequencies. The NFL was at pains to ensure that these ran interference free, since they’re key to the success of the game; and I’m happy to report there were no problems at all. The fact that we were given a ‘base’ in the press area meant we had some of the best seats in the house. And unusually for me, I actually got to see some of the event. Mind you, as a rugby fan, I can’t say I fully understood the game.
After the final whistle, the press conference areas were the next port of call, since they’re known locations where unlicensed equipment can suddenly appear; though luckily not at this game. After this it was a matter of collecting up my test equipment, and joining the queue to get out of the car park, as the NFL leaves Wembley for another 12 months. In fact NFL Commissioner Roger Goodell has stated that a second game could be added for the 2010 season – so I could be doing this twice next year….
