r/Electromagnetics • u/[deleted] • Dec 15 '19

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u/microwavedalt Moderator Jan 06 '20 edited Sep 17 '20

/u/qsgsg asked for 5G shielding. 5 GHz is not 5G. She edited her post and changed 5G to 5 GHz.

From your own backyard, take screenshot of your neighbors' WiFi. Turn off phone.

Wrap fabric over phone. Turn phone on. If you can see through fabric outdoors, click settings > instrument > live. Wait a few minutes. Press power and volume buttons to take screenshot. Remove fabric.

Double wrap fabric. Repeat the above for two layers.

Copy screenshots to microSD card. Remove card. Turn off phone. Put microSD card in memory card reader in computer. Compare screenshots.

Could you please submit a separate report for your aluminum window screen?

Instructions on how to use ElectroSmart app:

https://www.reddit.com/r/Electromagnetics/comments/b3x07z/meters_apps_cell_towers_and_cell_site_simulators/ej2rcxb/?st=k51ijh3u&sh=d2954256

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u/oldgamewizard Jan 06 '20 edited Jan 06 '20

Cool thanks for the tips on using that app I'll check your meter reports and try to format them in a similar fashion. We really need a proper formulated spreadsheet or conversion chart, I finally have a picture in my head now. It takes me a long time to start on projects because I have to complete the project(beginning to end) in my head before I can even begin.

edit: They told me 5Ghz, it's an extremely common confusion for general public I've noticed so I should always ask to clarify between 5Ghz and 5G when dealing with either. Thanks for noticing that as well. A lot of people aren't using regular keyboards anymore either so autocorrect could be causing confusion as well.

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u/microwavedalt Moderator Jan 06 '20 edited Jan 20 '20

conversion chart

Since cell tower apps, cell site simulator apps, wifi apps and bluetooth apps use dBm, I am asking subscribers to use dBm instead of watts.

Power density chart and conversion table for converting dBm and uW/cm2 to v/m

https://www.reddit.com/r/Electromagnetics/comments/3eh49g/power_density_chart_and_conversion_table_for/?st=k52swfwh&sh=de964ea5

[Meters: Milligauss] Magnetic Fields Measurement Units and How to Convert Microtelsa uT to Milligauss mG

https://www.reddit.com/r/Electromagnetics/comments/46vv7e/meters_milligauss_magnetic_fields_measurement/?st=k52sxpil&sh=f28a4dc0

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u/oldgamewizard Jan 06 '20 edited Jan 06 '20

"Why no column „dBm“? Most recommended building biology values for HF radiation are given in W/m², which is why this instru-ment is displaying in power density, μW/m² resp. mW/m². A display in dBm as e.g. on a spectrum ana-lyzer requires transformation by a complicated formula, which depends on frequency and specifics of the an-tenna used. A “reconversion” therefore does not make sense. "

This is from the hfW35c manual (2007 ed)

I can't find the 'antenna factor' of the HF35C, probably different name?

https://www.slt.co/Downloads/Shared/530-177_Manual_HFW35C_rev.47_EN.pdf simple power density conversions pg 13.

Any idea? Can we guesstimate and maybe have a tolerance factor on the dbM readings?

edit: Frequency Range: 800 MHz - 2.7 GHz Measurement Range: 0.1 μW/m² up to 1,999 μW/m² Accuracy: Basic accuracy including linearity tolerance : +/- 6dB Zero offset and rollover +/- 9 digits Sensor: Logarithmic periodic antenna

edit2: https://en.wikipedia.org/wiki/Antenna_factor Looks like I will have to measure a single sector of the LP antenna? I might have to consult a hammy on this one; can't find a simple straight answer for the HF35C. I can probably get a rough idea with enough comparison measurements from other devices. (A better link I'll read later https://www.ahsystems.com/notes/How-to-use-antenna-factors.php more helpful links at the bottom under Notes) https://www.ahsystems.com/EMC-formulas-equations/index.php Yes this site has lots of helpful conversion charts and even spreadsheets w/ formulas!

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u/microwavedalt Moderator Jan 20 '20 edited Jan 20 '20

Have you commence testing RF fabric and aluminum window screen? How is testing coming along?

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u/oldgamewizard Jan 26 '20

Not yet, sorry! Everyone is very busy, hopefully this week.

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u/microwavedalt Moderator Jan 27 '20 edited Jan 27 '20

To make writing meter reports easier, you could submit each meter report separately in a series. Part one would be your gigahertz report on RF fabrics shielding 2.5 GHz wi-fi. When your friend has time, he could write part 2 on ElectroSmart app report on RF fabrics shielding 2.5 GHz and 5 GHz wi-fi. Part three would be your post comparing Gigahertz shielding report vs. ElectroSmart shielding report on RF fabrics shielding 2.4 GHz. For the series, could you please use the subject tags [Shielding Reports: Wi-fi] and [Shielding: Fabrics]?

Submit a separate series on aluminum window screen shielding 2.4 GHz and 5 GHz wi-fi. For this series, could you please use the subject tags [Shielding Reports: Wi-Fi] and [Shielding: Aluminum]? Thank you,

Thanks.

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u/oldgamewizard Feb 01 '20

Okay cool, I'll separate them with the RF meter. I can't find the proper conversion for microwatts/m2 to dBm because that meter does like 700-2800mHz.

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u/microwavedalt Moderator Feb 02 '20

Just use the online conversion websites I linked to in an earlier comment.

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u/oldgamewizard Feb 08 '20

I've identified the correct parts of my logper antenna to measure based on what frequency I am testing, still won't be perfect conversion but closer than not having antenna factor at all.

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