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 3. GQ EMF EF Meter RF Spectrum Power Analyzer
 Pre-Sales Questions on 2 Usage Cases
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MegaBurn

USA
4 Posts

Posted - 02/05/2019 :  20:32:49  Show Profile  Reply with Quote
Hello,
I have a few pre-sales questions and need some advice...

A power company used eminent domain to force an easement across my front yard for a 138kV electric transmission line. The nearest conductor (of 3) will be roughly 200 feet off my front door, bathing my house in some mix of EF, MF, and LF (sub-RF) EMF. The house has a metal roof, which may provide decent EMF & EF protection, but I may need to install sheet metal under the siding. Before the line is energized I need to take baseline or ambient background measurements for EF, MF, EMF, in various places around the house. Afterward the line is energized, I want to mount the meter at whichever spot has the highest measurement (from that transmission line), for ongoing monitoring, similar to how people monitor ambient radiation levels with a Geiger-Muller counter. Will also check the house for wiring problems, leakage from appliances, etc.

Would the EMF-390 be well suited to continuously monitoring ambient EF, MF, EMF radiation?
(e.g. similar to how a GMC-600 looks well suited to continuously monitoring background alpha, beta, gamma/x-ray radiation)

Another forum thread mentioned a few instances of interference from the battery charger circuit when USB is connected ( https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=5777 )... Is this a known issue, which will be fixed soon? If I buy an EMF-390 before its fixed, to avoid this interference issue, will the unit operate normally on USB power, without a battery, and if so, at what amperage (min mA)?


I have another one-time usage, to survey EF/MF/EMF radiation levels around a plasma cutter and arc welder, for minimum safe distances for workplace safety, sensitive electronics, CNC controller, and desktop PC. The plasma unit is a Thermal Dynamics PakMaster 100 XL Plus, input 480V 26A AC3, output 112V 80A DC with high frequency pulsed DC arc pilot (lil EMP machine), which has a reputation for generating strong enough EF/MF noise to kill small animals (half joking), and this sort of equipment has been known to damage or destroy heart pacemakers, hearing aids, etc. The arc welder is a Lincoln Electric Ideal Arc CV-300, input 480V 30A AC3, output 37V 400A DC, with an actual tract record of frying a few cell phones and about a dozen credit cards. For the survey, I plan to take measurements at various distances, with the closest being the maximum safe rating for the EMF-390, or up to about a foot from the equipment.

What are the maximum safe EF, MF, RF values for the EMF-390?
(e.g. above which the device may be damaged or destroyed, especially MF)

Is the EMF-390 modular, can the sensors (coils) be easily detacted from the PCB? Could I put them in a wand with a short shielded extension cord and put the meter in a shielded box? (i.e. similar to how the same can be done with the GM tube in a GMC-500/600)


Thank you,
Chris
Reply #1

EmfDev

855 Posts

Posted - 02/06/2019 :  10:56:25  Show Profile  Reply with Quote
You don't need to remove the battery, the battery charging circuit will be completely stopped when fully charged.

It's not easy to dettach the sensors since they are soldered. and Yes the EMF-390 should be able to log data.

As for the how high are mf/ef/rf, we haven't experience that one. Maybe very very high.
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Reply #2

MegaBurn

USA
4 Posts

Posted - 03/24/2019 :  03:05:59  Show Profile  Reply with Quote
EmfDev,
Thanks for replying. Few more questions about the EMF-390, if you don't mind...

Is there an easy way to attach an external antenna? ZLM mentions that and calibration briefly in another thread, https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=6424 and you mention the EMF-380 has an antenna socket for AM/FM only, here https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=5516 , but in another thread there is mention of an audio jack in roughly the same location, https://www.gqelectronicsllc.com/forum/topic.asp?TOPIC_ID=6740 ... there is no mention of these features in the user guide PDF file (as of 2/3/19).

Any model updates coming soon? EMF-390v2? Maybe with a 5GHz band on the spectrum analyzer?

Is there a preference for people to order from the old store ($118) over the new store ($119)? I found you guys via Amazon ($125), but will order directly.

Reading forum posts and reviews, it seems like a lot of people are interested in detecting wifi signals. Have you considered using a wifi chip in passive mode (or modified to be strictly passive) to gather info about wifi devices? This could provide detailed info on channel usage for sorting out conflicts or surveying crowded wifi environments, and maybe identify devices hiding from regular wifi (e.g. sort of stuff that is wifi but a smart phone needs a special app to connect to, including cameras, DVR's, IoT gadgets/sensors, actual "spy" gadgets). Maybe it could also occasionally switch to active wifi to upload log data, say on a schedule.

Does the high voltage tube in a geiger counter generate enough EF/RF noise to cause issues with EF/RF readings? e.g. if a EMF-390 and GMC-600+ were side by side in the same pocket or backpack? I'm thinking about getting a GMC-520, 520+, or 600+, but will probably wait for something like a 620+ or 700 (600+ with environmental sensors + TVOC + GPS, maybe cellular).

Is news posted anywhere on product development? Have a newsletter?


Thanks,
-Chris
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Reply #3

EmfDev

855 Posts

Posted - 03/25/2019 :  10:58:26  Show Profile  Reply with Quote
The audio jack is not an official feature of the EMF-390. That's why it is not in the user guide.
However, the current EMF-390 model has that jack for earphones. It will automatically turn off the speaker clicks or alarm if you plug in an earphone to the jack. And can hear sounds from the earphones.

For antennas, no external antenna DIY for MF/EF. But there is a DIY antenna for general RF.

There's no plan in adding 5GHz band as of now or new 390 model.

It doesn't matter where you order, we will ship you the latest one we have. But support said the new store offers an option with extended warranty.

The GMC-600+ will affect the EMF but not EF/RF reading unless you turn on the WiFi.

We don't usually post new product development. You can always email support.

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Reply #4

MegaBurn

USA
4 Posts

Posted - 03/26/2019 :  01:47:42  Show Profile  Reply with Quote
EmfDev,
Thanks... Order placed, 1x EMF-390, via new store. Didn't see an option for extended warranty, subscribed to a newsletter, and noticed the shipping prices differed, $5 new store, $8 old store. Included a note about interest in future EMF & GMC models.

-Chris
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Reply #5

MegaBurn

USA
4 Posts

Posted - 03/28/2019 :  20:57:27  Show Profile  Reply with Quote
Received the EMF-390 today (3/28), much faster shipping than expected. Seems good, some of the readings are surprising, but I expected a learning curve. The alarm beeps remind me of an anomaly detector in STALKER, puts a bit of a nostalgic twist on hunting for "anomalies" in wiring, appliances, etc. Being in a narrow hollow and having a metal roof, my house is really quiet, 0 EF/MF/RF readings pretty much everywhere, and a sort of weak diffuse (flat) background noise on the various spectrum bands.

After I get a feel for it, I'll post a review on Amazon.

Thanks,
-Chris
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Reply #6

EmfDev

855 Posts

Posted - 03/29/2019 :  08:40:57  Show Profile  Reply with Quote
Thanks Chris. You can change the speaker sound in the Menu. Looks like you're not close to a cell phone tower. That's good! You can see RF picks up when at your WiFi or you're using your cellphone.

Edited by - EmfDev on 03/29/2019 08:49:02
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Reply #7

Stephan

Germany
8 Posts

Posted - 04/04/2019 :  01:04:26  Show Profile  Reply with Quote
I have a question about the sound output (audio jack).
Is the volume changeable and can e.g. a WLAN noise (Tock... Tock ...) be distinguished from DECT (faster Tock... Tock...).

Thanks,
Stephan
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Reply #8

EmfDev

855 Posts

Posted - 04/04/2019 :  08:37:42  Show Profile  Reply with Quote
Hi Stephan, you can change the beep volume from the main menu. You can also try to change the alarm type to ghost and go to RF Browser mode.
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Reply #9

Stephan

Germany
8 Posts

Posted - 04/04/2019 :  08:58:37  Show Profile  Reply with Quote
Thank you for your answer.
Please let me know if you can hear the sound of the radiation source:
WLAN (Tock... Tock ...), DECT (faster Tock... Tock...), radar and so on.

Only hearing the alarm with headphones is rather uninteresting for me.

Many thanks
Stephan

Edited by - Stephan on 04/04/2019 09:00:47
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Reply #10

EmfDev

855 Posts

Posted - 04/04/2019 :  09:23:18  Show Profile  Reply with Quote
The sound is not exactly 'tock'. But it picks up more signals with a chord less phone compared to wlan.
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