Hello there


All modern smartphones incorporate LTE., Orthogonal frequency multiplexing.Also known as multicarrier modulation (MCM), along with CDMA code division multiple access both are forms of wideband modulation.

Yep, you're correct and I wasn't thinking of it in terms like that, I was thinking more of the meter he might be using and not having much in the form of input selectivity or an ability to reject multiple frequencies, maybe more like Broad band, but to your point, yes, I misspoke the term. As I mentioned before, without knowing the setup, its hard to know what's really going on. Stay Safe and Healthy!

 

I concur. You seem to be a man of integrity which is rare nowadays.
So...unofficially welcome to misfit Island I'm sure you fit right in.

Well thanks for the kind words. I've been designing PCB's for 30+ years now and before that an engineering tech in a communications company that's long gone now. That said, I don't know everything and I can prove it! If I'm wrong, I'm wrong. (that's happened before too) I just always know that sometimes things are not always what they seem to be and unless you know what and how something is done, you really don't know, (And that's just on the things I might know about.) As someone you might remember, (depending on your age) Gary Owens said about an Expert. "An Ex is a former has been, and a spurt is a drip under pressure." To that I added, "I don't want to be an expert, I'll settle for knowing a lot about it, but never everything, otherwise, you're not learning. ;-) Stay Safe and Healthy!

 

Well outside my area but I can't help feeling that xchcui's question deserves something better than vague obfuscations

Obfuscation is also applied to programs to ensure intellectual property (IP) protection through reverse engineering prevention.
We try to do our best with the information given by the thread starters often times woefully inadequate as you just witness.

 

What kind of instrument were you using to measure this? My guess is it is utterly insufficient to capture anything of real value, especially if it's just a generic "EMF reader", which is essentially just a broadband RF power detector and some smarts to map it to values to display on the screen.

If you actually wanted to check the output of a cell tower, you would probably use a spectrum analyzer and a calibrated receiver antenna. Then you could capture not only the frequency spectra the tower covers, but also use zero span mode to capture the duty cycle or change in power vs. time. A cell tower will operate in TDD like modes where sometimes it is transmitting, sometimes receiving, sometimes on different frequency bands, and with different output power depending on how far away the client device is (the cell tower and client device both have transmit power control).

 

Thanks a lot for all the answers.
It is a generic emf meter which suppose to sense RF power density
between:50MHZ-5GHZ,without any selectivity.
After reading all your responses,i guess that the emf meter
that i used is not suitable for that task indeed.(regardless of
the reason that make the spike's reading).

Thanks again for your help

 

And now we all know, "The rest of the story".

 

A very basic accessment might use non proprietary instrument.

The Doctors researching biological effect of RF or RF physicists example referenced p.34 of the pdf
https://www.icnirp.org/cms/upload/publications/ICNIRPrfgdl2020.pdf
all use specialized equipment there are many different organs, tissues, nerves and cells.

There does exist an insurance underwriter regardless of the old articles stating that the industry cannot
monitor and insure RF tower safety the industry non-the -less is rapidly expanding in that direction.
https://safedynamics.com/#rf-work-aware

The thermal effects from high power RF emitters is well known. We used HERO, HERF, RADHAZ and EMCON Alpha when servicing exposed RF systems on my old ship in the dark ages.

https://www.crfs.com/applicationstory/naval-emcon-emissions-control/
https://www.globalsecurity.org/military/library/policy/navy/nrtc/14226_ch3.pdf

 

Many years ago while living just one block away from one of those towers, I asked why the signal of my mobile (data, no voice) when in my office, many many blocks away, I could hear in my PC's audio output, while at home it never happened.

I was told that all was matter of the distance mobile / tower governing the mobile's power output.

Here, the focus is on the tower, so I am not sure if the above could suggest an explanation.

 

Many years ago while living just one block away from one of those towers, I asked why the signal of my mobile (data, no voice) when in my office, many many blocks away, I could hear in my PC's audio output, while at home it never happened.

I was told that all was matter of the distance mobile / tower governing the mobile's power output.

Here, the focus is on the tower, so I am not sure if the above could suggest an explanation.

It's QRP (reducing power consumption), the phone modulates power to get X link budget for good quality calls.
https://urgentcomm.com/2012/07/01/a-balancing-act/

Slightly OT.
We would play 'games' with Soviet SIGINT satellites to see how long we could escape detection by reducing transmit power to low levels, switching frequency ranges and antenna types. One of the TU-95's would do an overflight when they found us.
http://www.russianspaceweb.com/tselina.html

When their plane arrived our planes would play 'games' with them.
https://theaviationist.com/2017/12/...e-story-of-the-phantom-upside-down-near-bear/

 

RE: jkenny Joined Aug 15, 2009 4 Mar 6, 2021Mar 6, 2021 26

<<What kind of instrument were you using to measure this? My guess is it is utterly insufficient to capture anything of real value, especially if it's just a generic "EMF reader", which is essentially just a broadband RF power detector and some smarts to map it to values to display on the screen.>>
Not always. For example GQ390 having well elaborated spectrometer functionality yet range from DC to 6 GHz. However sad to tell it spectrometer function is not very good above 1 GHz. Or other example RF-Hack-001 having 50 kHz to 6 GHz and much more developed spectrometer part, yet metrologically bound to relative units instead of physical. Thus, may use them both paralelly, one is telling how many V/m or A/m or W/m^2 means 100% of other instrument scale.

 

Many years ago while living just one block away from one of those towers, I asked why the signal of my mobile (data, no voice) when in my office, many many blocks away, I could hear in my PC's audio output, while at home it never happened.

I was told that all was matter of the distance mobile / tower governing the mobile's power output.

Here, the focus is on the tower, so I am not sure if the above could suggest an explanation.

Ironically, you were too close for a good signal and your phone was cranking up the power to get a good connection.

This image it the horizontal radiation pattern and you can see the antennas are designed to radiate away from the tower. Very close to the tower, there are nulls.

 

RE: Yaakov and antenna directivity graph.

Willing to opponate to terms in the picture "very low". For example 5G substation some 300 meters near the University student campus. Four transmitters in about 20 meters high. Each transmitter works near 5 GHz with 180 W of output power. As the near zone works about 200 people staff in 1./st and 2.nd floors high and other 200 people are typography and big newspaper redaction about 150 meters afar, I have measured field geometry there. Sorry I dont remember the figures itself, but nearest zone 10-50 meters afar from antenna pole thus 20 meters below it the intensities was 50% to 300% of ICNIRP normative but "patchy" - two steps right or left and field changes some 4-8-fold. In the 50th meter field became bit better uniform however irradiation of staff in the 2nd floor was slight over normative whist in 1.st floor was about 80-90% of max permittable. In 200 m distance there was no any difference between the floors and irradiation was about 50% of max max. In student place 300 m afar it was about 20-30% of normative. So... my only concern is what will happen if (according pronounced plans) similar substation will work one in each next 200 meters.

 

RE: Yaakov and antenna directivity graph.

Willing to opponate to terms in the picture "very low". For example 5G substation some 300 meters near the University student campus. Four transmitters in about 20 meters high. Each transmitter works near 5 GHz with 180 W of output power. As the near zone works about 200 people staff in 1./st and 2.nd floors high and other 200 people are typography and big newspaper redaction about 150 meters afar, I have measured field geometry there. Sorry I dont remember the figures itself, but nearest zone 10-50 meters afar from antenna pole thus 20 meters below it the intensities was 50% to 300% of ICNIRP normative but "patchy" - two steps right or left and field changes some 4-8-fold. In the 50th meter field became bit better uniform however irradiation of staff in the 2nd floor was slight over normative whist in 1.st floor was about 80-90% of max permittable. In 200 m distance there was no any difference between the floors and irradiation was about 50% of max max. In student place 300 m afar it was about 20-30% of normative. So... my only concern is what will happen if (according pronounced plans) similar substation will work one in each next 200 meters.

I don’t think the TS was talking about 5G. Most likely given the comments about interference with PC speakers, it was 900Mhz 2G or 3G. Those antennas are higher and the radiation pattern has dead spots close to the tower. A different thing.

 

A map showing the contribution from all cell sites is more comprehensive about the actual zones
and their coverage.

The Universities that are involved in the test sites have been video conferencing during past year due to lock down and travel restrictions.
The department heads and all their technical support have benefitted from the down time by focusing on improving the educational aspect
during lock down. When we say "5G roll out and RF safety" now we can include the role of higher education as a significant part
in improving our understanding and having the tools and the program to do that correctly also involves teachers.
Hopefully not jumping ahead too far however the awarenesss that some university programs are becoming more involved
and the back log of this situation is a concern.

The many years of careful FCC rule making involved legality issues. What is available will be conciderable progress
for some and not enough for others because the rate of technological change in this field has out paced government in turn education.
Amoung the latest global infrastructure scenarios there was lengthy study and continues. But right now there is good amount of determination to get what is being used globally into release. It is up to the US providers that made development and revisions to keep their end of the deal with the collaboration that they are presently working with and some of those issues such as indemnity will need to be addressed to the public.

 

Thank you Delta prime for your earnest input, I can relate to the frustration. I was'nt aware that Motorola solutions was still that active or held that much weight with telecom exposure safety. It is my understanding that global interest having stakes in larger trillion populations are poised to grow will need to be indemnified or those liable can include tower, information providers, equipment manufacturers and real estate investment trusts.

As an enthusiast looking in and from what I have been able to understand is that experts from the larger US information provider stake holders ( Verizon, ATT, T mobile and others) are often brought in to advise FCC staff in order to obtain sufficient material about matters also FCC allows exparte a chance to input, but the formal decision-makers for the Commission, Right now are those shown on this revised chart. The past 35 years slowness suggest US innovators forced offshore to survive.
https://www.fcc.gov/sites/default/files/ogc-org-chart.pdf