GPS Tracker Antenna & Faraday cage effect

Thread Starter

neomem2023

Joined Mar 1, 2023
2
Hello,
After a recent bad experience due to my bike being stolen. I'm trying to install this GPS Tracker (S7 model) in my bike (S7 model) :
1677691829619.png

Inside :
1677691981479.png

I have install it here in the bike frame:
1677692219633.png

The problem is, that once the GPS tracker inside, it is impossible to catch ths GSM neither GPS signal. Very probabely due to
Faraday cage effect.

Could someone help me to fix that ? can I for example connect the GND power to the bike frame, by coil rolling... or something like that to allow the GPS tracker to catch GSM & GPS signals ?.

Thank you by advance for your support
 
Last edited:

nsaspook

Joined Aug 27, 2009
11,743
You're basically asking for the impossible if the antenna is totally inside a electrically sealed enclosure. Hide it in/under the seat, in a 'fake' plastic light, plastic water bottle, etc ...
With an external antenna unit, the main body could be hidden in the tube with a small wire and antenna to the seat or some other external covertly exposed position.
 
Last edited:

Thread Starter

neomem2023

Joined Mar 1, 2023
2
You're basically asking for the impossible if the antenna is totally inside a electrically sealed enclosure. Hide it in/under the seat, in a 'fake' plastic light, plastic water bottle, etc ...
With an external antenna unit, the main body could be hidden in the tube with a small wire and antenna to the seat or some other external covertly exposed position.
Thank you for your reply. I'm just wondering technical solution to keep the gps inside the tube, maybe your external antenna solution could be good.
By the way, I noticed that when I pulled out the charge power cable from a the small hole in the downside bike frame, the GSM antenna worked again (communication are estabilished) but not the GPS signal. That's why I was thinking that it sould have a way to create antenna waves propagation outside the "faraday cage" by cable, coil or by the cage contact itself :)
 

nsaspook

Joined Aug 27, 2009
11,743
Thank you for your reply. I'm just wondering technical solution to keep the gps inside the tube, maybe your external antenna solution could be good.
By the way, I noticed that when I pulled out the charge power cable from a the small hole in the downside bike frame, the GSM antenna worked again (communication are estabilished) but not the GPS signal. That's why I was thinking that it sould have a way to create antenna waves propagation outside the "faraday cage" by cable, coil or by the cage contact itself :)
The key is proper antenna (a random cable in a hole can couple RF energy from the outside but it likely won't be an efficient antenna) outside and working efficiently so your bike can get located.
 

Janis59

Joined Aug 21, 2017
1,717
Strictly teoretically, Faraday Cage effect is unidirectional. From outside nothing is coming into (Law: the sum of electric field inside the Cage is ultimative zero, because all the charges are straighforwarg floing to outer wall). So... this principle makes no any big problem to transmit from inside toward outside, however sure, the antenna impedance will be affected strongly, therefore in real life, the signal strength will diminish. If sea-container made of 2 mm steel what is earthened by 4 Ohm 3 meter long wire (thus linked via significant inductance) at 868 KHz using 3 km capable LORA(TM) data station, the 99.9% good transmission packets distance diminishes from those 3 km to about 30 meters. There we hanged another retranslator and got the demanded 3 km.
Yet in case of bicycle seems 1) receiving the GPS is important and 2) the LTE-4G signal transmission in far distances from tower is as well important. Thus, You should avoid of any FC. Just place it in somewhere hidden plastic part. Under the seat. In hole drilled into steer handles. In light sources. Into some decorative addendum like rosy elephant dool sitting on the luggage shelf or something similarly innocent "girly". The plastic mirrors on the steer is very great place.
 

Janis59

Joined Aug 21, 2017
1,717
Just reminiscence. At end of 80-ies once I let my bicycle stay near Opera house, where I sticked it to lantern stake with 3 cm thich high quality steel tross and 2 cm thick sector key what then was stated as "million secrets". I jumped only inside for 60 seconds to give the letter to secretary in hands. When out, already bicycle had gone but my tross was cut by one move - seems military cutter is allmighty. Then I came to the Sweden. Just some time ago had ended the cutting hands for thieves. Bicycles was everywhere, not locked, just put in stack, and no-one is steeling it!!! Then I went to Finland, there was the same. Snow was falling some weeks ago, but I see the bike staing at the latern stake full under snow, it means staying maybe month. I asked - how this can happen, why owner is so uncareful. Answer was, probably he was drunk and forgot where he left it.... Then I was going to Sweden hundreds of times, and each year the bicycle steeling became a larger and larger problem thus I see the frame chained to lantern having no wheels, no seat, no steer; I see the front wheel chained to stake but frame and rear wheel stolen, I see the rear wheel and frame chained but front wheel stolen. etc etc. So, the old good times when Sweden cut the hands off the thieves had been gone and nowadays there the bike "freedom fighters" are the same active as at us. The cancer invading the World is on the growth phase.
 
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