Severe OTA Interference From New Digital Services Tower - Page 5 - Canadian TV, Computing and Home Theatre Forums

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post #61 of 149 (permalink) Old 2011-02-18, 07:06 PM
 
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Originally Posted by GerryB View Post
Hi Trip.

Im cool with it except the part about the TV station getting back to me. They did as they were quite concerned, but it was A-Channel that I contacted, not RogersOmni1. The interference on A-Channel turned out to be not so bad so I told them as soon as I knew. Channel 60 though, which is RogersOmni1, is still a big mess. The CTV/A-Channel people were responsive the same day.
I've corrected it. Tell me if you like the correction or if more changes are necessary.

I don't know if having it on the front page of RabbitEars will do anything for you, but I figure it's worth a try, if nothing else.

- Trip
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post #62 of 149 (permalink) Old 2011-02-18, 07:11 PM
 
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Perhaps I missed it in the thread, but what did Rogers Wireless say when you contacted them?
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post #63 of 149 (permalink) Old 2011-02-18, 07:14 PM Thread Starter
 
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GeorgeMX -

If you have an engineering contact for Rogers Wireless let me know. Id send them an email.

Trip-

I like the way you put the story together. It is actually over 3 KW ERP not 1 kW. The LTE is 1.2 KW and there are 2 PCS transmitters at 955 watts, and an 800 MHz transmitter at 600 watts ERP.
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post #64 of 149 (permalink) Old 2011-02-18, 07:29 PM
 
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Originally Posted by GerryB View Post
Trip-

I like the way you put the story together. It is actually over 3 KW ERP not 1 kW. The LTE is 1.2 KW and there are 2 PCS transmitters at 955 watts, and an 800 MHz transmitter at 600 watts ERP.
I modified it to say 3 kW among "a few" transmitters.

I'm glad you like it.

- Trip
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post #65 of 149 (permalink) Old 2011-02-18, 07:40 PM
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Gerryb,
to satisfy my curiousity, do you have an oscilliscope there, where u could measure the period of that tone coming from that piezo speaker?
From that you could calc the frequency of the tone ur hearing. Wonder if it'd be around 15 KHz?
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post #66 of 149 (permalink) Old 2011-02-18, 08:01 PM Thread Starter
 
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It is 4 KHz. right in the middle of human hearing. I double-checked
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post #67 of 149 (permalink) Old 2011-02-18, 08:41 PM
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Gerry remember when that kid had the pirate radio going in south-Ottawa. There was one reporter who seemed more interested than most. I will see if I can pluck his name from the thread. Seems to me they were from the Citizen or the Sun papers.

Edit: PMed you the reporters coordinates.
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post #68 of 149 (permalink) Old 2011-02-18, 09:36 PM Thread Starter
 
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Thanks Jake I appreciate it.

Looks like I am going to have to do something. Im a bit horrified now that Ive proven I can light up a small LED lamp with the power from only about a 7 inch antenna (about the size of my head). See the video I just did below. The LED is bright and flickering with the various cellular and PCS linkups

http://s214.photobucket.com/albums/c...crowaveLED.mp4

That's a projector screen in the window to the left of the lamp
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post #69 of 149 (permalink) Old 2011-02-18, 10:51 PM
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Wow! I am amazed and worried at the same time. I will admit I don't know a lot about power transmission but that seems pretty excessive even for Homer Simpson.
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post #70 of 149 (permalink) Old 2011-02-18, 11:26 PM
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Gerry,

Seriously,... upload your vids on youtube with comments and a link to this thread!

We can make it go viral through CHCH, CTV, CBC news.

3D SSH III with ZZ4 refl. http://imageshack.us/user/jmsdigital
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post #71 of 149 (permalink) Old 2011-02-19, 08:42 AM
 
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Gerry are you sure they did not install some cell panels right above you too.

Attic CM 4248 at Buffalo,M4 at Buffalo.VHF yagis at Toronto .
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post #72 of 149 (permalink) Old 2011-02-19, 11:24 AM Thread Starter
 
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Just checked my building. No there is nothing on my roof, just the roof across the street. The antennas on the roof across the street are tilted downward at an angle that makes them point straight at my apartment.
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post #73 of 149 (permalink) Old 2011-02-19, 11:41 AM
 
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GeorgeMX -

If you have an engineering contact for Rogers Wireless let me know. Id send them an email.
Rogers Wireless had to file an application with Industry Canada to get the experimental license. The application form and associated correspondence will provide the name of a contact person at Rogers responsible for the application. Contact the local section of Industry Canada responsible for managing RF licenses and ask to speak with the official responsible for the Rogers experimental license. Request the name of the contact person at Rogers or a copy of the license application and correspondence. Industry Canada may not want to investigate causes of interference but they have an obligation to assist you in resolving the problem by identifying the license holder.

You should contact the Rogers individual and explain what you believe has happened since they activated the experimental transmitter. Ask for their cooperation in confirming that the problem is originating from their cell site. You might suggest arranging a time and date to turn the transmitter off for a brief period to confirm that the problems you experience are directly related to the experimental transmitter. You should also invite them to visit your home to confirm the problems for themselves and witness the effect of turning the transmitter off and on again. The license and operation is experimental so they should not refuse to conduct a brief shutdown to confirm the problem.

Your email should be civil, rational and to the point. You don't need to go into side issues about RF hazards and safety code 6. Anything that looks like a rant will quickly put you and your issue into the crazy category. Threats to send stuff to the media or make publicity trouble for Rogers won't aid your cause. Your objective should simply be confirmation that the new transmitter is causing problems. Copy your correspondence with Rogers to the Industry Canada official handling the file. If the issue becomes a public concern or you contact a politician for assistance, a 'paper trail' will aid your cause, assuming you are always civil in your correspondence.

There are several possible outcomes from the suggested test. One, the interference remains because the source is actually something other than the cell site. Two, the interference goes away and comes back when the transmitter is cycled off and on. In this case, the transmitter is causing the interference but it may be doing so legally, meaning it is operating within the parameters set by Industry Canada and in compliance with safety code 6. You would have to prove the transmitter is not operating in compliance with the license to get action from Industry Canada.

Lots of homes have experienced interference from broadcast and other transmitters operating completely within their approved technical parameters. AM stations are particularly good at inducing interference into audio equipment because every diode junction in an amplifier can demodulate the signal into audio frequency sound - intelligible music and voice. In the early days of radio in the 1920s and 1930s, people often listened to radio stations from miles away using a 'crystal set' that drove headphones. These devices were unpowered and used only the energy in the radio transmission to function.

The interference problem in modern equipment is usually caused in the amplifier or other device by poor shielding or a design that lacks suitable bypass filtering to short RF frequencies to ground. Electronics are often 'value engineered' by removing components that low cost manufacturers decide is not necessary for the equipment to function. I have heard stories of companies taking reference designs provided semiconductor makers and picking components off the board until the equipment stops working. An RF bypass capacitor for the DC power trace on a circuit board may cost 5 cents but leaving it out may not cause any problem unless you happen to be close to a transmitter site...

Your television set is experiencing problems because of the signal ratio between the cell transmitter and the the broadcast stations. You may be getting tuner overloading due to the high signal level. You would probably experience the same or worse problems if someone located an analog TV transmitter on the same channel with the same power in the same place. You would see black sync bars and possibly an overlaid picture floating around rather than noise.

Experimental operation inside the current television band is part of the problem. The TV tuner has no filtering to block the unwanted signal. After the August 2011 transition, you should be able to install a low pass filter in your antenna line to block all frequencies above channel 51 and prevent tuner overloading. You could ask Rogers to provide you with a suitable filter.

The health and safety issue may deserve further consideration but if the estimated signal level is 17 dB below safety code 6 levels as reported in one of the posts in this thread, you are talking about a signal less than 1/50th of the allowable limit. If you choose to complain about this level of signal you a just entering the broad and unresolved debate surrounding safe RF levels.

Over the years there have been many instances of new services causing infererence with existing services. Back in the days of CB radio, some guy in a neighbourhood would get a CB set and wipe out reception on TV channel 2 because the second harmonic of the 27 MHz CB band falls in the 54 to 60 MHz assignment of the TV station. The CB radio could be operating legally but the signal level was sufficient to cause tuner overload and generate the second harmonic inside the TV tuner. The solution was a high pass filter to block the 27 MHz signal from getting into the TV tuner. In some cases, the CB owner might have to put a high pass filter into the antenna line to ensure that second harmonics from the transmitter (type approved and operating legally) did not get to the antenna.

In the case of the LTE transmitter, I would be very surprised if the transmitter is not fully compliant with the Industry Canada technical requirements. The transmitter is experimental in Canada but the equipment is commercially available and deployed elsewhere. The equipment manufacturer does not want to create problems for its customer, the wireless company, or be forced into an expensive retrofit program to correct a problem. Wireless companies spend huge amounts on equipment and when problems occur will force the cost of remediation back on the equipment supplier including the labour and inconveniece of swapping equipment. The telecommunications equipment manufacturer doesn't 'value engineer' like the low cost consumer electronics guys.

Over the years, many homes and businesses have experienced interference to their electronics when other parties legally install and operate RF transmitters nearby. At the end of the day, I think the most likely cause of your problems will be your consumer electronics and the use of channel 58 for the experimental transmission. Post transition, a low pass filter will keep the RF out of the front end of the tuner and should restore TV normal reception. As a goodwill gesture, perhaps Rogers could arrange for you to receive basic cable service until the channel 60 broadcaster puts a digital signal up below channel 52 and you get a low pass filter.
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post #74 of 149 (permalink) Old 2011-02-19, 12:25 PM Thread Starter
 
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Hi GeorgeMX

I dont disagree with anything you are saying. I calculated the 17 dB below safety code 6. Ive worked in radio-engineering for more than 15 years, dating back to my first days working for Nautel the broadcast transmitter manufacturer in Halifax just before I got my electrical engineering degree.

I believe that this is fundamentally different compared to interferences of the past that were manageable with common-mode chokes and shielding. The frequency in this case is simply too high and goes straight for the heart of the electronics. In the past and even now, broadcast transmitters would not be sited at 2000 watts ERP and only a few meters above where people live. 700 MHz may be the "perfect" frequency for them because it is high enough to have a small antenna but low enough to penetrate walls and cement with maybe a few dB loss. It also is therefore the "perfect" frequency for interference.

I havent sent anything to the media, but I am seriously creeped out that I can light up a lamp with the radio energy coming through my window. 17dB below safety code 6 is still above the Russian safety level and the level of a few places in europe.

You talk about electronics manufacturers cutting corners, but what about the corners that Rogers is cutting by not installing an appropriate mast for that kind of ERP? Especially in a residential area? In broadcast, the towers were always nice and high or on a mountain with the main beam pointed outward and not downward.

I will do my best to try to contact Rogers and see about having a solution, but I expect the worst since they plan on installing more and more of this LTE stuff at presumably very high ERP close to peoples homes to keep up with bandwidth demand.


Here's some happy bedtime reading from before the RF-safety crazies days that isnt a quack epidemiological study : http://www.feb.se/EMFguru/EMF/microwave-dna.html
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post #75 of 149 (permalink) Old 2011-02-19, 12:25 PM
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GeorgeMx,

I agree any communication with the suspect operator, Rogers, should be civil, etc. But if your insinuating that every form of consumer electronics known to man should have a Faraday Shield around it in order to function properly to accomodate Wireless operators all over the world, I think that's just going a little overboard.
Just face it, in a cellular system, they have no real need to be transmitting 1000 W ERP for any technology, anywhere. Much less in the city.
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