16-10-2018, 08:38
(This post was last modified: 16-10-2018, 08:41 by meteoestarreja.)
I think you will find this very interesting:
https://goughlui.com/2016/05/01/shootout...-compared/
A few things to consider (in my opinion):
- First of all, beware of local regulations on 433Mhz. Amateur operators are right there in that "neighborwood", and will be pretty easy to annoy someone IF you have an operator near you.
The fines can be a bad surprise if your regulator decides to pay you a visit.
I'll bet that almost every TX modules are "illegal" because of the chinese frequency stabilization and in other cases, the output power. The good thing is, those frequencies are not that populated and I think that almost no one will ever notice those tiny TX pcb, anyway, be mindful.
- Like Werk_AG said, sometimes the module will perform worse with 12V than with 9V, will heat more and probably will fail sooner.
- Also like Werk_AG said, some modules will change TX frequency by changing the voltage
Meanwhile, I invite you guys to check this:
http://www.image.micros.com.pl/_dane_tec....1-433.pdf
Like you will see, those RX modules will tipically work between 433.82 and 434.02 Mhz.
I saw TX modules transmitting outside those freqs - in 434.90 for example, so, going up on the power does nothing besides making higher the risk of RF polution and RX saturation
In the older TX modules (those with two small coils), even the antenna lenght could change the frequency ... by the way, those coils can be used to "tune" the frequency.
- If I was you and if possible, I would check thoses frequencies, then I would insist first on the TX antenna, second on the RX antenna, third on TX antenna and forth on RX antenna, at last, I'll check the RX antenna one more time just in case
I tried several antennas and modules and can say for a fact that the modules, even if they are alike, same model etc etc, they can perform different.
I found for example two equal modules, bought on the same seller with almost 1Mhz difference on the frequency. Altough RX module is sensitive, that can add some surprises to the end result.
One of them was transmitting way outside of RX range, so, I had almost nothing received on RX when using those specific module, when I changed by the equal brother, voila, everything was good to go.
Some time ago, I made a few tests and after measuring the right frequency and trying some different antennas, I can say that I managed to receive the TX signal from about 1 KM from it. Yes, it was on a relative open space with a few houses and trees along the way, but, the signal was there without any changes on the power.
- Like Werk_AG also said, is better to use the antenna right on the SMA plug not using coaxial cable, the less the better, in fact, the best results I ever had was with the antenna directly on the module bypassing the SMA plug, oh, wait, with so many tests my TX PCB does not have any module soldered, it's "hanging" with cables to connect the module to pcb and making life easier when I remember to test something different on RF
Sorry for the long post but I felt I have to say something about this.
My final advise is, power can help but isn't everything
https://goughlui.com/2016/05/01/shootout...-compared/
A few things to consider (in my opinion):
- First of all, beware of local regulations on 433Mhz. Amateur operators are right there in that "neighborwood", and will be pretty easy to annoy someone IF you have an operator near you.
The fines can be a bad surprise if your regulator decides to pay you a visit.
I'll bet that almost every TX modules are "illegal" because of the chinese frequency stabilization and in other cases, the output power. The good thing is, those frequencies are not that populated and I think that almost no one will ever notice those tiny TX pcb, anyway, be mindful.
- Like Werk_AG said, sometimes the module will perform worse with 12V than with 9V, will heat more and probably will fail sooner.
- Also like Werk_AG said, some modules will change TX frequency by changing the voltage
Meanwhile, I invite you guys to check this:
http://www.image.micros.com.pl/_dane_tec....1-433.pdf
Like you will see, those RX modules will tipically work between 433.82 and 434.02 Mhz.
I saw TX modules transmitting outside those freqs - in 434.90 for example, so, going up on the power does nothing besides making higher the risk of RF polution and RX saturation
In the older TX modules (those with two small coils), even the antenna lenght could change the frequency ... by the way, those coils can be used to "tune" the frequency.
- If I was you and if possible, I would check thoses frequencies, then I would insist first on the TX antenna, second on the RX antenna, third on TX antenna and forth on RX antenna, at last, I'll check the RX antenna one more time just in case
I tried several antennas and modules and can say for a fact that the modules, even if they are alike, same model etc etc, they can perform different.
I found for example two equal modules, bought on the same seller with almost 1Mhz difference on the frequency. Altough RX module is sensitive, that can add some surprises to the end result.
One of them was transmitting way outside of RX range, so, I had almost nothing received on RX when using those specific module, when I changed by the equal brother, voila, everything was good to go.
Some time ago, I made a few tests and after measuring the right frequency and trying some different antennas, I can say that I managed to receive the TX signal from about 1 KM from it. Yes, it was on a relative open space with a few houses and trees along the way, but, the signal was there without any changes on the power.
- Like Werk_AG also said, is better to use the antenna right on the SMA plug not using coaxial cable, the less the better, in fact, the best results I ever had was with the antenna directly on the module bypassing the SMA plug, oh, wait, with so many tests my TX PCB does not have any module soldered, it's "hanging" with cables to connect the module to pcb and making life easier when I remember to test something different on RF
Sorry for the long post but I felt I have to say something about this.
My final advise is, power can help but isn't everything