yes I know there is alot of discussion for this subject: 433 or 915 mhz telemetry, 433 is legal in europe, 915 in the US. Me ( in europe) 'must' use 433 mhz because it's legal, but I read it has alot of interefence with the usb hub?! (with a very short range as result). Does the 915 mhz telemetry any problems with that?
kind regards azerty09
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Just as a word of caution... Besides the fact that 900MHz is used by GSM - in some countries, it's also used by TETRA police radio. The usage by GSM means a ton of strong interference, because there are basically everywhere mobile phone towers.
It also means, the chance to be caught if you use those radios illegally is VERY high, because modern BTSs (GSM base stations) do a regular interference measurement and with BTS locations being so dense, especially in more populated areas, it's excessively easy to triangulate interferences. Then, TETRA base stations of some manufacturers actually actively scan for interference sources, especially, when the TETRA net is used/operated by the police.
Again, depending on country, this can end up VERY expensive, because it might not only be seen as "operating an unlicensed transmitter" but also as "interference with public communication systems" or "interfering with government communication systems", which can end you up pretty close to terrorism charges nowadays...
The 915Mhz ground station with the USB connection works fine.
3DR never produced a version of that board for 433Mhz because there is too much interference from the 480Mhz USB signal however that board has been cloned a ridiculous number of times and all of those clones have the problem that the original board (that was never produced) did.
If you buy a 433Mhz board set from 3DR it has 2 air radios with and an FTDI extension cable. That configuration works fine as well because the USB signal is a kept far away from the radio and there is no interference.
There was an issue with the 'groundside' USB 433MHz radio where the laptop USB system caused interference with the serial-to-USB converter in the radio that you connect to the laptop.
There are various workarounds using USB hubs etc however I think the most effective is to use two of the serial 'airside' radios which don't have built in USB (you just connect the module to your laptop using an FTDI cable).
If you buy the 433 radios from 3DR you will get 2x airside modules and a FTDI cable which should get around the USB interference issue you've been reading about
Cheers Paul
Hello, why should you use a USB HUB?
Using 900+ MHz will be more subject to interference becouse of mobile frequency.
Connect the 433 MHz directly to the computer, and use a extension cable for the antenna.