new search engine and GSM interference info [Telecom]

Over the past 5 to 6 weeks in several threads, we've discussed and argued the interference issues attributed to GSM cell phones.

At this point it's probably safe to write we now understand the whys and wheresfores of the multifaceted problem and I was just about to put a closure on my files about GSM interference this weekend when 2 interesting events occurred. One is a "new" search engine referred to me by an acquaintance, the other is a refinement on the GSM inter- ference problem's cause (as item (1) below).

The acquaintance suggested I use for research- related searches for its better results. Always wanting to learn new things every day, I gave it a try. The interface is clean like Google with the additional benefit IP addresses aren't tracked.

Searching for "GSM interference problems" (as I had done with not much success or relevance with Google) claims 1.3 million results found with those 1,3 million reduced to 48 unique results ranked by relevance.

Whoa! What a pleasant surprise. Each of the 48 results was relevant and pertinent, nothing like the eleventy-seven bazillion useless hits typically returned by other search engines.

Here's what I gleaned and learned from those 48 results by IXQuick:

  1. the problem is specific to GSM with TDMA, not CDMA. To wit:

GSM uses TDMA (Time Division Multiple Access), so each user transmits a short burst of information at a different time, so they don't interfere with one another. A GSM phone sends one packet (burst) of data every 4.615ms, or about 217 per second. Your speakers are being interfered with at 217Hz, causing the buzzing sound.

This does not occur with CDMA (Code Division Multiple Access). In CDMA, each user gets a different code applied to his signal, so the base station can separate the users apart that way. This allows all users to transmit at the same time, so the radio isn't switching on and off at 217Hz (or any other rate in the audio spectrum).

  1. shielding techniques for some GSM cell phones: placing the phone atop some of the anti-static bags used for hard drives seems to work.

  1. some solutions for those having problems with their hearing aids:

4, Texas Instruments forum video on GSM interference:

  1. another good article with thoughtful user comments:

  2. information about Tempest:

  1. a new appreciation and understanding for the banning of cell phones on commercial airline flights

  2. interesting background information about GSM supplementing the 1994 article in comp.dcom.telecom:

NONE of the above were found in any prior searches using any of the big 5 search engines (Google, Yahoo, Bing, CUIL, Ask).

It's going to be a cold day in Hades before I return to any of the conventional Internet search engines.

Reply to
Thad Floryan
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But here's one more data point. Doesn't affect my point of view that it's the responsibility of goods manufacturers to ensure that their products are not affected by interference in our increasingly noisy RF environment, but...

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Reply to
Dave Garland

Thank you for that URL! Another poster in an earlier thread mentioned that event but not the URL.

Hmmm, does anyone know if cellphone providers have a ringback capability? By "ringback" I mean some method to cause one's cell phone to ring; not having landlines anymore I can't call myself. :-)

Reply to
Thad Floryan

It bothers me that it's UL certified but UL doesn't have a certification for not being susceptible to common sources of radiointerference. And I guess control mechanisms for gas stoves and ovens aren't subject to FCC regulation.

My stove/oven has an electronic control, but it's just for the clock. The gas jets are controlled with knobs. Gas appliances with electronic controls of the gas jets have been available for 10 years or more.

Reply to
Adam H. Kerman

I've heard that Orange (PL) has a way to let your phone, even if an oldy without an alarm clock, call you up at a preset time to

*simulate* an alarm clock. No idea, tho', whether any US carrier offers a service like that :-) . Cheers, -- tlvp
Reply to

If they contain digital circuits, and then the FCC does regulate emissions _from_ the stove or oven. But they don't concern themselves with interference _to_ them.

Reply to
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