This blog will deal with issues related to electromagnetic and Cellular radiation and it is written by an EHS person (Electromagnetic Hyper Sensitive person).
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Few weeks back I got a new Car DVD/GPS unit for my small Fiat Panda.
I am an EHS person and the car was already tested and found to be low EMF car.
In addition I have installed RF protection film over the windows to block the RF coming from cellphone towers along the side of the road.
2 weeks ago I installed the new system in my car and was amazed that the system emitted RF radiation even after the WIFI was turned OFF and the Bluetooth was not operating.
I reported that on my latest post: http://norad4u.blogspot.com/2017/06/how-can-people-stand-car-multimedia-gps.html
It took me few days of trial and error + testing the unit with an RF meter to find out where the radiation is coming from, it was the GPS antenna.
This a video I did after finding out that the GPS antenna was emitting the radiation https://youtu.be/85yf96bamX4
I first thought that it must be a mistake, or a bug since I thought there should not be any RF emission from a GPS Antenna, since GPS units do not emit any RF, right? wrong!
Today I found-out that the GPS antenna main pin has 3.3V on it, I was begging to think why.
Later on tonight I came to the conclusion that the antenna must be an ACTIVE ANTENNA.
Did some research and it turns out that there are Active antennas for GPS out there and that some GPS units need them, and some come-with them.
So this in an other thing to test when you buy a car or a DVD/GPS unit for the car, does the GPS unit is Active or Passive.
I am still trying to work this out , maybe it is possible to just connect a passive antenna and all will be OK, maybe I will need to find a switch in the software or GUI. I hope I will manage to do it and to make this unit a NO RF EMISSION unit so I can use it in my car.
In the picture - the DVD/GPS Car unit in question, on my lab desk
The Solution:
I got and installed a passive GPS antenna.
Then I tested the RF radiation emitted from it, there was no radiation measured.
The GPS receiver gets all the data and gets the signal from the satellites.
It seems that the RF emitting Active Antenna has no added value.
This is perfect example of RF Exposure without any real need.
In the picture - Active (right) Vs Passive (left) GPS antenna
In the picture - no RF emission from the Passive antenna
Why is it radiating?
The unit I have has WIFI (which I turned off) and 3G data if you use dongles for communication (for getting updates of traffic) so I don't think there is a real function to the RF emission. I think it is just a RF signal that should not be there.
I don't think it was part of a tracking system as well (which is usually also relaying on UMTS or GPRS modems).
Active GPS external antenna gets 3.3V on the coax cable and use it to run a LNA (Low Noise Amp), basically a filter+amplifier.
The unit identify it is active by the load, and push the 3.3V over the coax.
If there is no load (in case of passive antenna) the unit does not find load, and does not push the 3.3V over the coax.
Please see - http://www.trakgps.com/en/index.php/information/gps-articles-information/67-gps-antenna-factsheet
I am guessing the Active GPS antenna that I got with my DVD/GPS car unit was one of the following:
1. Badly designed not to include an RF Faraday cage over the LNA amplifier in side it .
2. Badly designed to have the 3.3V reach the antenna it self and not just the LNA.
3. A malfunction antenna.
4. Maybe all active antenna are working this way - this is way I urge you all to use your RF meter to test as your GPS units with external antennas.
In this case, I used the RF meter right a way to make sure I turned the WIFI and Bluetooth correctly.
Then I saw the RF from the active antenna.
It took me a while to understand what and where from, but if I did not use a RF meter it would have take me a lot more time and cost me many more headaches.
So, the Bottom line is:
1. Use your RF meter every time you need to buy, install, operate a new device, you can never know.
2. If you have a GPS unit with external antenna make sure it is not active. If it is active measure it with the RF meter and let me know what you saw.
3. If you are find the external antenna to radiate, and you prefer it not to, try to change it with a passive antenna.
2 years ago I even built my own set of floor stander Audio speakers to go with my Cambridge Audio Receiver and CD Player. I made sure they will be low ELF speakers (magnetically shielded) and I use low ELF speakers cables.
I also love Car audio systems.
4 years ago I got DVD+GPS unit for my old Mazda 3 car (which I since then sold). The device came with build in WIFI+Bluetooth card. It was not possible to turn the Bluetooth or WIFI OFF in this device. At the end, I had to removed after making sure it could not be turned OFF .
2 years ago I got an 4.4 Android car DVD+NAV system from my Mazda 6. This device allowed me to turn off the WIFI+Bluetooth from the GUI setup with no need to crack it open and remove the cards.
Few weeks ago I ordered an additional new Android DVD+NAV 2DIN system for my secondary car (my Fiat Panda). It cam by the mail few days ago, and tonight I managed to install it.
So far I found no way to turn the Bluetooth of this device off, and it keep scanning for devices, emitting RF radiation in side my partially RF protected Fiat Panda.
I relay hope to find a way to disable the Bluetooth without taring it open and taking the card or chips a part.
I can't imagine how people can drive with the Bluetooth and WIFI turned on inside their car, with a smart phone and not feeling the radiation, it is so strong, as specially if you have a 4G smartphone.
I imagine that even if they don't feel it, it effects them and reduce their driving capabilities and performance. I am an EHS person, so I can't stand the radiation from the Bluetooth hand-free unit or the smart phone (if I had one) for more then few minutes, but other people drive with these devices scanning and transmitting in side the car metal box for house.
I think that the lesser evil of using a cell phone in a car is using a in car cell phone with an external antenna. The exposure of the driver in this case are lower then when using a hand held cellphone inside a car , and usually lower from his exposure from RF radiation from cell tower.
I made this video in my low RF environment so the background levels in this video are lower than 0.0005mW/m2.
The RF exposure near the drivers head was around 0.02mW/m2 , peeking to 0.8 mW/m2 (once) but most of the time even lower than 0.01mW/m2.
The RF exposure near the external antenna was higher.
The radiation issues in hybrid cars are turning to be a real thing. Reports from around the world about measurements of high radiation levels are coming out.
All "regular" cars radiate from low frequency electromagnetic sources like the alternator, car's electric system, and the layers. In hybrid and electric cars you have to add also the electric motors, the electric batteries, and the power conductor from the batteries to the motors.
In some of the cars there are also some high frequency radiation sources like the car's Bluetooth system, car tracking systems, thewireless key, Wi-Fi and mobile communication systems, and of course the passengers and driver mobile phones.
Using your mobile phone inside your car ( a close metallic object), other than taking the driver's mindoff the road, results with you espousing yourself to high levels of radiation.
Below is a like to an article that summaries measurements of several cars, both hybrid and "regular". The article is in French but you can get some of the info from the pictures or you can translate it.
Is the real cause of sudden acceleration in Toyota vehicles related to electromagnetic interferences? Toyota claims that the causes of the sudden acceleration are out-of-position floor mats and sticky accelerator pedals. In the USA claims are made that the real cause is electromagnetic interferences that cause the electronic acceleration pedals to malfunction.
POLICE officers in Lancashire are suing their own force for injuries allegedly caused by their radio system. (System Private/Profesional Mobile Radio TETRA).
Lots of people are driving their car while holding a cell phone. They Slow down, while not paying attention to the traffic on the road, in order to read a new SMS.They read the newspaper (while driving) and then checking if a new SMS arrived. The bypass a car and then check if some one had called. They slow down and search the cell phone memory for some one they can call.
When a driver use the phone while driving his mind is distracted and the radiation in the car does not help, and may cause the brain and neurological system to slow down his reflex and to make his reaction time longer.
Using a hand free kit does not help, the driver mind is still distracted and his reaction time is getting longer.
Stop it! You need to understand this is very dangerous! A cell phone should be use only in emergency. Using it while driving may lead to an emergency!
An Australian TV program that shows how dangerous it is to use your cell phone while driving.
