hi,
i use fastract supreme 20 , 663g. I face alot of problems about signal quality. at+csq responses become under 10 in some places. Bc of the weak signal, modems connect to server very hard. sometimes they get stucks. I have added many controls in the software to reduce this problem. For example i check at+creg response periodicly. But these controls does not solve the problem permanently.
What i want to know is if there is a way to increase signal quality. I guess it is not related with the software. I think it is about the antenna. I use standart antenna wich wavecom sends us. it hasnt got a cable. it is short(5 cm) and pluged in directly. Do you know any other antenna which performs better? Or which way can i follow to get rid of the problem?
Using an antenna with a longer cable might help by allowing you to position the antenna in a more favourable location; but beware that cables are “lossy” - so that the advantage can easily be lost due to the extra attenuation in the longer cable!
Be sure to specify high-quality cable and connectors!
There are very many specialist suppliers of antennas - including GSM antennas.
Ask you Distributor if they know of any local to you, and google “GSM antenna” or “GSM aerial”.
With antennas, Size Matters - all other things being equal, a bigger antenna will give you a better signal.
For best performance, the antenna needs to be specifically tuned to the frequency band that you are using; eg a “dedicated” 900MHz or 1800MHz aerial will give better performance than a “dual-band” 900-1800MHz aerial.
What you need is an antenna with higher gain; high-gain antennas also tend to be directional.
For highest gain, you will need something like this - a “Yagi” antenna:
Note that there is an inherent limit in the GSM technology on the maximum distance (due to timing) from BTS to mobile - if your nearest BTS is simply too far away, then there is nothing that can be done!
Remember that the range of any radio-based communiucation system is finite.
In particular, remember that there are still many areas that do not have (usable) GSM Coverage - therefore, any system that relies upon GSM has to have some contingency for areas where coverage is simply not available.
If you are selling a commercial system, you need to be careful to set appropriate expectations with your (potential) customers…
I will ask my distributor about antennas but i guess they wont give me a logical solution. To force them giving me the best solution, i need to know the parameters of antennas about rising signal quality.
Should i look for an antenna which has higher gain than mine? What other parameters are there for an antenna to provide better signal? Does better signal mean larger size?
Why do you think that?
A distributor of GSM devices should be ideally placed to understand these issues; moreover, your local distributor should be familiar with the local conditions that you are likely to encounter, and what suppliers and specialists are available to help you.
I would expect a distributor of GSM devices to stock a range of suitable antnnas - or, at the very least, have close contacts with suitable suppliers.
The principles are the same regardless of application - so any standard text on antennas should help!
Again, search for local specialists.
Isn’t that exactly what I said?!
The impedance & VSWR also need to be correct - but that should be a given if you specify the antenna for use with your device.
