Oh the troubles we've seen...
The install of our new wireless systems is proceeding with a bit of a speed bump along the way. The 3732 systems are working very well with no RF interference. The new IEM systems have been another story. The frequency sweep done by Sennheiser a couple of months ago seems to not be accurate anymore. All of our IEM systems are in the B band, which is 626 – 662 Mhz. Sennheiser assigned all of our IEM systems based on open channels in that range. Since some of those are no longer available and we didn’t know they were gone, we got ourselves into a big mess.
It appears that at least one if not two TV stations have come online since the sweep was originally done. The almost square waves you see are TV broadcasts. We were told to use some of those frequencies for our systems. Bad idea as you might imagine. At the time we did not have access to the data you see in the picture. We knew we had problems and only survived the weekend because of the helical antennae and strong output from our IEM transmitters. Even with those, our worship team had RF dropouts. Without knowing where to move frequencies, it was just a complete guessing game.
We contacted Sennheiser who let us borrow the NET1 interface. The NET1 allows you to attach almost any Sennheiser receiver and do a frequency sweep using the available range of the receiver attached. The NET1 system in built into the 3732 boxes we have but not the 300 series IEM. Since they are in different bands we had no way to see what was happening. Once we did see the data it was a shock to us to see how little space is available. We managed to get all our systems in the open spots but have no margin left. We are going to purchase a NET1 box so we can continue to monitor all the systems across all our campuses. There is a new band being released by Sennheiser called the G band which will live between what is currently A and B bands for them. We are planning to exchange a few of the IEM systems we have for the new band in hopes of opening up more space for us in the future. We just have to pray no one decides to put up another TV channel in the 650Mhz range.
It appears that at least one if not two TV stations have come online since the sweep was originally done. The almost square waves you see are TV broadcasts. We were told to use some of those frequencies for our systems. Bad idea as you might imagine. At the time we did not have access to the data you see in the picture. We knew we had problems and only survived the weekend because of the helical antennae and strong output from our IEM transmitters. Even with those, our worship team had RF dropouts. Without knowing where to move frequencies, it was just a complete guessing game.
We contacted Sennheiser who let us borrow the NET1 interface. The NET1 allows you to attach almost any Sennheiser receiver and do a frequency sweep using the available range of the receiver attached. The NET1 system in built into the 3732 boxes we have but not the 300 series IEM. Since they are in different bands we had no way to see what was happening. Once we did see the data it was a shock to us to see how little space is available. We managed to get all our systems in the open spots but have no margin left. We are going to purchase a NET1 box so we can continue to monitor all the systems across all our campuses. There is a new band being released by Sennheiser called the G band which will live between what is currently A and B bands for them. We are planning to exchange a few of the IEM systems we have for the new band in hopes of opening up more space for us in the future. We just have to pray no one decides to put up another TV channel in the 650Mhz range.
posted by Jason at 12:27 PM
4 Comments:
wow.... i will have to post a copy of my sweep in that band to make you feel better.
A wise man once told me, ". . . wireless is hard. . .". Oh, that was you Jason. I feel your pain.
hopefully you won't have to worry about the frequencies come February with those tv stations being forced to go elsewhere!
Dude, I have no idea what any of this means. Here's what I do know. I couldn't do what I do if it wasn't for guys like you doing what you do.
Keep up the great work.
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