17-10-2018, 22:26
(This post was last modified: 17-10-2018, 22:58 by meteoestarreja.)
Hello engolling,
no need to thanks, that's why I'm here, it's excelent when I can give a little of my knowledge and at the same time, take so many from you guys, I think that's the hole ideia of sharing.
So, honnestly, I already tested dozens of those tiny transmittors and I'm not saying that it's completely random to get a "good" one, but, it's true that I tested some weird ones even from the same batch.
Depending on the models it's even possible to "tune it" and solve the deviation problem, if you have no chance to test it with some kind of equipment, I suggest to use something like hornychz used, an RTL SDR.
With a cheap dongle, you can use a raspberry or a computer with sharpsdr for example to get an ideia of what is going on with your transmitters. It won't help that much about power measurement but definetly will help about frequency deviations, bandwidth used, RF saturation and easely check if input voltage will shift the frequency for example.
In the first use of the dongle probably you will have to calibrate it, but that's easy if you pick a signal that you now for sure it's frequency, preferrably a signal with narrow bandwidth and near from 433Mhz.
With this you can even test several locations and have an ideia wich ones are better for your purposes.
If I may also suggest, if coaxial cable is needed, you can use a (much) better one, other than rg58. Start with LMR cables for example, to get an ideia, check this small table
https://en.wikipedia.org/wiki/Coaxial_cable
you can even find better tables with much more data on it, this is just a start
Another thing that would help, is using a diretional antenna instead of an omnidirectional one, that ensure that almost every energy is directed to the right spot.
I hope that this would help
no need to thanks, that's why I'm here, it's excelent when I can give a little of my knowledge and at the same time, take so many from you guys, I think that's the hole ideia of sharing.
So, honnestly, I already tested dozens of those tiny transmittors and I'm not saying that it's completely random to get a "good" one, but, it's true that I tested some weird ones even from the same batch.
Depending on the models it's even possible to "tune it" and solve the deviation problem, if you have no chance to test it with some kind of equipment, I suggest to use something like hornychz used, an RTL SDR.
With a cheap dongle, you can use a raspberry or a computer with sharpsdr for example to get an ideia of what is going on with your transmitters. It won't help that much about power measurement but definetly will help about frequency deviations, bandwidth used, RF saturation and easely check if input voltage will shift the frequency for example.
In the first use of the dongle probably you will have to calibrate it, but that's easy if you pick a signal that you now for sure it's frequency, preferrably a signal with narrow bandwidth and near from 433Mhz.
With this you can even test several locations and have an ideia wich ones are better for your purposes.
If I may also suggest, if coaxial cable is needed, you can use a (much) better one, other than rg58. Start with LMR cables for example, to get an ideia, check this small table
https://en.wikipedia.org/wiki/Coaxial_cable
you can even find better tables with much more data on it, this is just a start
Another thing that would help, is using a diretional antenna instead of an omnidirectional one, that ensure that almost every energy is directed to the right spot.
I hope that this would help