A Sudden, Severe Case of RFI
By Trip Ericson on Friday, February 18 2011, 18:40 - News - Permalink
How would you feel if you suddenly had tons of RF (up to 1 kW ERP) being beamed directly at you from a few hundred feet away on 700 MHz? That's exactly what happened to Gerry B., as documented in this thread on DigitalHome.ca recently.
He first noted the interference because it was interfering with his analog TV reception, which has suddenly become quite miserable.
In the course of investigating, he determined that it was an experimental transmitter put up by Rogers, one of the major communications companies in Canada, in addition to a few other transmitters on the same building. Their permits calls for the use of more than 3 kW ERP combined from the antennas seen in this picture.
He started testing other devices to determine the amount of interference observed. Here's what happened when he turned on his electronic keyboard.
(If your browser does not support the <video> tag, please click here to view.)
Gerry also attached a diode to a multimeter and found 1V floating around in his apartment. He also used a Shotkey diode, a capacitor, an inductor, and a speaker to make a Piezzo-Microwave. With no battery attached... I'll let the video tell all.
(If your browser does not support the <video> tag, please click here to view.)
He wrote a letter to Industry Canada, who is responsible for the licensing of broadcast stations in Canada much like the FCC is in the United States. Here is the response he received.
Industry Canada does not conduct general public investigations and is not responsible for identifying, locating, or resolving interference affecting the operation of such devices as AM/FM radios, televisions, stereos, telephones, etc. Our mandate as defined by legislation (the Radiocommunication Act), does not support these activities, however, for your convenience we have created a set of "self-help" information materials in form of videos and brochures title "Cutting through Interference...". These are intended to help the public better understand all the factors involved regarding the cause of interference and how it can be resolved.
In this self-help material, we offer various suggestions as to how the public can identify the source of the interference and what steps should be taken to correct the problem. Some of these steps are very simple and require no technical expertise. More complex problems may require the assistance of: a qualified technician at a local service shop, the service provider (cable operator, broadcaster, etc...) or the service utility (telephone or power utility).
Self-help information is available to the public on the Internet. Visit our web site at: http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/h_sf06086.html
As with interference complaints made to the FCC, Industry Canada was unwilling to do more than send an unhelpful form letter in response.
Gerry has also contacted one of the TV stations receiving some of the interference and received a concerned response, though the station with the worst interference is owned by Rogers - same as this new transmitter - and thus he has not tried to contact them. He is now looking to the media in general and at any other options that people suggest. Hopefully something can be done to alleviate this issue.
Comments
WOW!
Outrageous!
I can't believe that they're allowed to produce this level of interference to the general public. How can Industry Canada justify not following up on such a solid case of unwanted RFI! (And, yes, I know the FCC here in the states is at least as bad...)
In the mid 60's, I had an aunt and uncle who made the mistake of buying a house only a couple hundred yards from a 5kW AM radio tower. The audio of that radio station could be heard, loudly, through the speakers of their console stereo (those big wooden piece-of-furniture stereos that were in vogue in the 60s) whenever its power was on and it was set to "phono". It came through in the background of the audio on their TV too, and no AM radio in the house could receive ANYTHING but that station! It came through across the whole band!
They moved within a year.
(Admittedly, todays consumer electronics tend to be less prone to this sort of interference, than those of the 60s.)
What kind of device is this that rogers is transmitting with?
Folks, this is exactly what we'll get when white space devices become a reality. It won't be 1 volt of RF but it will be a lot of interfering signals in close proximity. The parties pushing white space devices will then trot out the old tired and patently false arguments that "no one watches TV with an antenna anymore."
Nevermind, I see that it is 4G LTE that they are transmitting with, which is basically OFDM on the downlink side.
In terms of the interference.. while this installation isn't the best PR in the world, I do have to take the somewhat contrarian opinion that this is an indication of inadequately-shielded/filtered consumer gear.
That said, if he's reading 1V/m inside his apartment, it would be interesting to know whether this site is in compliance with RF safety rules.
Belongs to Rogers, huh? Are they not one of the largest cable operators in Canada? (as in, as Ryan suggests, they really don't care if there's interference to OTA broadcasters???)
Doug, I'm not sure if this is just a case of inadequate shielding. Maybe for the audio breakthrough but definitely not for the TV reception issues. Rogers is a telecommunications conglomerate so they deal with wireless, cable, phone, you name it... Along with Bell they are like Verizon and at&t.