Advice on GSM Antenna Placement on Rear Panel of Unit (Drawing attached)
Just looking for a little advice on GSM antenna placement on a unit i am working on. The box is made of mild steel and is powder coated. It has a 220V Mains supply at 50Hz going in at the rear also along with a PWM fan,
I have attached a drawing of the back of the case in the hope that someone would be able to help me best position it (if its even suitable to go at the back)
Plan is to use those small stubby antennas about 50mm in height with a connector on the back to screw it on to,
A few questions really,
- Will the 50Hz mains signal interfere with the GSM Reception?
- Will the 12V PWM Fan interfere with GSM reception?
- Is it ok to place the antenna on the rear of a mild steel powder coated box
- Is it ok that the antenna cant see over the top of the box or will i lose all signal coming from that direction?
Thanks again,
Stephen
If the antenna is external of the box, all the influences from the objects you mentioned will have minor importance.
Yes Antenna will be outside the box but pointing straight up and not over the top of the box but you see no problem in this or any interferance from the 50Hz 220V AC or anything like that no?
The "stubby antenna" is designed for mounting position perpendicular to the metal ground plane. If you mount it in parallel to the metal box, close to the box, the antenna will not radiate as designed. Mounted this way, radiation pattern and input matching will change a lot.
I only drew a cross section of the back, height is correct but the box is actually about 500m in width,
So antenna will be perpendicular to the longer metal side, should this be ok do you think?
I don't understand your intended orientation. The antenna wire should be pointing away from the metal surface. The antenna wire must not be in parallel to any metal nearby.
ok fair enough,
Well yes the plan was that it would go paralell to a metal side but you think not a good idea (which makes sense), Straight out does not really suit either though as it will get broken off,
When people put WiFi cards in their computers the antenna is normally parallel to the computer chassis, How does this work so?
These antennas with rotary joint can be oriented at variable angle. Parallel to the metal is the worst case for electrical performance.
If the antenna is known to operate in parallel to a metal chassis, parallel to the metal boundary, the length could be designed to achieve the correct resonance frequency. However, I don't think that the rotary joint WiFi card antennas are optimized that way, because the orientation is unknown.
This doesn't mean that your antenna will fail completely. It only means that it radiates less efficiently, and antenna mismatch losses are increased.
Ok thanks for your help, sure ill just some experimentation with it and see,