Directed RF at our Office Causes Headaches

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owb24
Posts: 30
Joined: Thu May 27, 2021 4:26 pm

Directed RF at our Office Causes Headaches

Post by owb24 » Wed Jun 02, 2021 10:38 pm

Hi Guys,

Could anybody explain where the RF energy in below graph might be originating from? It was measured with a Narda RadMan 2 XT which is a broad banded device. It seems to be a directed RF signal towards our office and it is likely the culprit causing employees of our company to have strong headaches, all at the exact same time. Anybody seen something like this before? Thanks for any input.

Wally
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tim_rtd
Posts: 180
Joined: Fri Jun 30, 2017 11:34 am

Re: Directed RF at our Office Causes Headaches

Post by tim_rtd » Wed Jun 02, 2021 11:48 pm

Is there a freq showing anywhere there?

radiolistener
Posts: 91
Joined: Thu Jan 25, 2018 10:48 pm

Re: Directed RF at our Office Causes Headaches

Post by radiolistener » Thu Jun 03, 2021 6:39 pm

What is the frequency of this emission? If RF emission is so strong and can cause headache, then you can easily measure it's frequency with a frequency meter with piece of wire inserted into input connector.

Does neon lamp glowing in the hand when this thing happens? You can also use compact fluorescent lamp instead of neon lamp for testing. If the lamp glows in your hands, then this is a strong indication that you are indeed under the influence of powerful electromagnetic fields. In such case stop working and leave area because if you stay in such environment for a long time it can harm your health.

MMcC
Posts: 6
Joined: Fri Jun 04, 2021 5:01 am

Re: Directed RF at our Office Causes Headaches

Post by MMcC » Fri Jun 04, 2021 5:56 am

RadMan 2XT is an RF Exposimeter operating in the ranges 900KHz-60GHz (E-Field) and 27MHz - 1GHz (H-Field). While it is good for detecting exposure across the bands, it won't isolate the frequencies or provide any directional information.

owb24
Posts: 30
Joined: Thu May 27, 2021 4:26 pm

Re: Directed RF at our Office Causes Headaches

Post by owb24 » Sun Jun 06, 2021 4:28 pm

@radiolistener
@MMcC

The frequency for this signal is probably around WiFi 2.4 GHz. At least we have measured such a signal previously with this device: https://fieldsatwork.ch/products/expom-rf/

Who ever is doing this, is surely hiding under common frequencies.

Recently, I have been using Pluto SDR for measurment. I notice something strange around 70 MHz. Anybody?

https://we.tl/t-2i6KqhOpO5

MMcC
Posts: 6
Joined: Fri Jun 04, 2021 5:01 am

Re: Directed RF at our Office Causes Headaches

Post by MMcC » Mon Jun 07, 2021 4:01 am

It is hard to say. I don't think anyone has published a clear list of frequencies, noted effects such as headaches and power densities.

owb24
Posts: 30
Joined: Thu May 27, 2021 4:26 pm

Re: Directed RF at our Office Causes Headaches

Post by owb24 » Mon Jun 07, 2021 5:34 pm

@MMcC

There is a wide range of publication on the subject. Here is an example:


https://www.researchgate.net/publicatio ... nse_system

radiolistener
Posts: 91
Joined: Thu Jan 25, 2018 10:48 pm

Re: Directed RF at our Office Causes Headaches

Post by radiolistener » Fri Jun 11, 2021 4:41 pm

owb24 wrote:
Sun Jun 06, 2021 4:28 pm
Recently, I have been using Pluto SDR for measurment. I notice something strange around 70 MHz. Anybody?

https://we.tl/t-2i6KqhOpO5
It doesn't looks like a strong emission.

Here is example of a strong carrier at 6 MHz:
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owb24
Posts: 30
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Re: Directed RF at our Office Causes Headaches

Post by owb24 » Mon Jun 14, 2021 11:44 am

@radiolistener

Which software are you using? I would be interested in using it myself.

Attached is a signal we measured around 70 MHz, it pulsates in 8 blocks - strange. It seems to be directed at our office - away from the office, the signal vanishes. Any idea?
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radiolistener
Posts: 91
Joined: Thu Jan 25, 2018 10:48 pm

Re: Directed RF at our Office Causes Headaches

Post by radiolistener » Mon Jun 14, 2021 5:08 pm

owb24 wrote:
Mon Jun 14, 2021 11:44 am
Which software are you using? I would be interested in using it myself.
HDSDR, it is available here and supports different hardware through ExtIO plugins or sound card input: http://www.hdsdr.de/

I'm using custom ExtIO plugin for my custom DDC SDR (Digital Down Conversion Software Defined Radio) radio receiver based on a high dynamic range ADC and FPGA.
owb24 wrote:
Mon Jun 14, 2021 11:44 am
Attached is a signal we measured around 70 MHz, it pulsates in 8 blocks - strange. It seems to be directed at our office - away from the office, the signal vanishes. Any idea?
It looks very like FM broadcasting stations on OIRT FM band (65.9...74 MHz). Such FM band is used in Brazil and Eastern Europe. It was used in USSR as the main FM broadcasting band.

If this is the case (I'm sure for 95% it is), then pulsating is just because they transmitting the music :)

By the way, the signal strength is just 16 dB above noise floor, such low signal cannot cause effects like headache and other things you're talking about. It is pretty safe level.

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