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Block 28 wireless


Marc Hoppe

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I rented a Lectro Sr camera hop from a pro audio place in NYC and they gave me (actually the producer, who picked it up) block 28. 

I had a conversation with the rentals manager who assured me that block 28 was clear and I would have no issues, even after I discussed the current laws with him.

I have been on another shoot all day and have not really had time to deal with this, but I am more than a bit concerned.

What problems or issues should I expect to face?

Thanks.

Marc

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" the rentals manager who assured me that block 28 was clear  "

pretty clear!

you can get additional info by doing a search on jwsound.net, RAMPS, or elsewhere, including manufacturers websites!

no more TV stations there!!  

A lot of wireless mic users have already left, too!

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In most places, for the time being, you will have really good luck with 28.  Just look for the used freqs (Qualcom & AT&T have bought some of the upper spectrum), avoid those freqs, and you'll be okay in most situations.

The main exception to this is that some venues (certain stadiums, studios, etc.) have already banned use of these frequencies in their facilities, so if you're in a facility where you'll need to coordinate frequencies with them, they might not let you use them.

The FCC has decreed that June 6th is the cut-off date for Block 28 (and up) usage.  That doesn't mean it won't work after that date, it just means that technically, it's a no-no.

<i>*** Correction:  June 12th, 2010 (not 6th). ***</i>

John B.

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The FCC has decreed that June 6th is the cut-off date for Block 28 (and up) usage.  That doesn't mean it won't work after that date, it just means that technically, it's a no-no.

To put a finer point on it, the June ban is for frequencies from 698mHz to 806mHz, which includes a good bit of Block 27 also.

...and I had the date wrong.  It's June 12th.

http://www.fcc.gov/cgb/wirelessmicrophones/

John B.

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Thanks again John.  I haven't paid too much attention to this because I don't have any gear in the block 27-29 range.

I'll be back in an arena tomorrow where my block 22 gear was slammed last week and I wanted something out of that range.  I was cleared for block 21 for my wireless, but blocks 22-25 were pretty full. 

I have been dealing with a whole host of different personal issues (flooding) and this gig has taken a bit of a back seat, especially since this client keeps changing their mind about everything on this job.

People like you and your willingness to share information are what makes this group such a valuable resource.

Thanks.

Marc

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  • 3 weeks later...

I've been noticing that 700 MHz has started to become an unpredictable place. Not clear at all. The different players that have bought up the space have started firing up and testing.

Here's a copy of a Spectrum Scan I did at Carnegie-Mellon in Pittsburgh, PA on November 29th of last year.

pittsburgh.jpg

http://www.parkeraudio.com/pittsburgh.jpg

The live broadcast show had 16 wireless microphones, 24 wireless two-channel headsets and four IFB channels. This was the first time I saw activity in the 700 MHz since analogue TV went off the air. No real rhyme or reason to the frequencies. Really stinks and made my job a pain. 

Analogue TV was predicable and, therefore, manageable. This is sporadic, unpredictable and, frankly, a nightmare. I would recommend staying clear of 700 if at all possible. I have heard of other traveling RF Techs seeing the same kind issues in other cities.

As an aside, a major cable news outlet in New Jersey hosts AT&T cell arrays on their building. Last I heard AT&T was planning to start 700 MHz tests in January. Which was bummer for the news outlet considering they had fully installed Lectro 28 block system (I think around 30 wireless and IFB's)

There is one hope. If you own block 29 there is a small sliver of frequencies that WERE NOT sold. The “D Block” (758-763 / 788-793 MHz) was put up for auction and never received a winning bid. As of now, there has been no talk about bringing it back up for sale. So I have been recommending to people to use this narrow block if you have to use anything in the 700 MHz world. Of course, as of June 12th of this year...it'll be illegal.

Kevin Parker

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I have been on the road in the US for the last 6 weeks, using block 28. Started in Chicago, then visited St. Paul, MN. Spent some time in Durham, NC, then traveled through TN, GA, and AL, and finally, FL.

Block 28 has been clear every time I've used it. Pretty much the whole block completely free.

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ynpredictable?? sure!  but aside from fixed TV channels, which were really only a small part of the total interference picture at any given place and time, actual clear frequencies have always been a variable. I could get a couple of wireless operating on each block shown on your scan, but 16 wireless mic's (not even counting the 24 IEM's, and any wireless intercom's) is way more than "a couple", and typically needs to be spread over multiple 25 MHz blocks, no matter where you are!!

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Just trying to make the point that when a rental company tells you "700 MHz is all clear" ....it ain't true.  They are trying to squeeze every last rental day out of the gear.  I don't blame them, I know the pain.  I sold off and replaced all my Lectro 28 and 29 gear last year and spent a fortune on getting all my antenna distribution re-blocked or switched to wide band. Took a lot of whiskey to make that pain go away.  For months I kicked myself for not working the stuff on a few more jobs.  Every time I would scan a location 700 MHz was clean as a whistle.  Then, in Pittsburgh, it all changed and I came up with the scan below.  After calling some other live broadcast RF Techie types I felt even better when they confirmed that they were seeing the same things.

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Test it! I have a block 28 set and it *was* a ghost town until very recently.

My cart has a block 28 VRT in the Venue, but in my bag i only have a 401 RX.

I don't know the exact frequency, but Verizon's LTE (4G network) is in the 700 MHz range. I KNOW they have LTE gear running in Boston and Seattle (for testing). I do not know about NYC or Philadelphia though. Verizon is ahead of the other guys with LTE rollout, and is supposed to have a decent network up and running in less than a year (rumors are that they will sell their first LTE phones very late 2010 or early 2011). Supposedly their network will be fully up by 2014. I don't know how far along the other LTE networks are.

I was on a job last week (in Philadelphia) and noticed a screen full of crap at two locations. A few days ago I was about 45 minutes outside the city and still saw a fair amount of noise on my 401 RX. The guy I was working with had a Block 28 411 and it was pretty clear. Those could have been flukes, but who knows. Maybe I'll take my 28 RX with me around town and do some scans.

Seeing how the SR is somewhere between the RX quality of the 401 and 411 I would suggest a quick check. If you are going to be very close to the camera, you will probably be fine, but if you are going to push the normal Lectro limits of range, I suggest a quick scan.

EDIT: I guess the jobs I did in Fall/Winter 2009 were a good 100 miles from Philadelphia (DE beach or Poconos). Everything I did locally was either on provided gear or I didn't use the block 28 stuff. I guess I need to go do some field scans.

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" even after I discussed the current laws with him. "

"operating this microphone system without a license is subject to certain restrictions: the system may not cause harmful interference; it must operate at a low power level (not in excess of 50 milliwatts); and it has no protection from interference received from any other device"

" technically, it's a no-no. "

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@JohnGooch Interesting! Last time I had issues finding a clear spot on 28 was on a Saturday. I was inside the Please Touch Museum and then inside a hotel at Penn's Landing.

So I have been driving around with my Block 28 201 RX with me and randomly taking scans around Philly. I realize it's not a lot of help to Marc in NYC, but the constant source I am seeing has been everywhere. It's possible it's something that will be national. I don't see anything on the LTE charts to say what it is. I think Verizon would fall on Block 29.

Here's the pictures of the Block 28 scans in Philly. The full vertical bar is the scanning line, not a source of RF. I was not able to find the RF noise I had experienced inside a few buildings recently (on a Saturday).

http://www.flickr.com/photos/xjohnpaulx/sets/72157623667036213/

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