Spektrum DSM X compatibility
- Thread starter Videoace
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RandyDSok
Well-Known Member
I'd have to refer you to the EU documentation for your radio since the standards/laws differ... but in the US I do believe the DSMX radios are backwards compatible with the slightly older DSM2 standard... I'm less certain about the 1st revision compatibilty but I don't think the newer radios are backwards compatible with the 1st rev...
Smoggie
Well-Known Member
You are correct. Any EU/UK spec Spektrum transmitter made in recent years do not support DSM2. If you have any old receivers that are DSM/DSM2 (i.e. with no DSMX support) then you are out of luck.
US transmitters as Randy said are different, they have retained DSM2 backward compatibility.
US transmitters as Randy said are different, they have retained DSM2 backward compatibility.
Yes, thanks for that info. Perhaps I'll fly in the USA!
Thanks. As I wrote to Randy, USA is the place to buy and fly. I wonder why the EU Spektrum txs aren't made backwards compatible.
RandyDSok
Well-Known Member
I was surprised by that as well... By not allowing backwards compatibility, they risk/encourage having more e-waste which isn't typical for either the UK or EU.
Smoggie
Well-Known Member
It's related to EU regulations on use of radio frequencies. The regulation in question is to avoid the 'blocking' of the 2.4GHz spectrum in areas that have many 2.4GHz users.
DSM2 uses two 'fixed' frequencies of the 80 that are available in the 2.4GHz band (the Tx actually selects two clear frequencies when it powers up). If you had 40 DSM2 users then the entire 2.4GHz frequency is fully 'swamped' and no one else could use 2.4GHz. The chance of 40 RC flyers all being in range at the same time is very slim but 2.4GHz is for a vast range of uses, not just RC. If they all used a DSM2 'type' system that used a fixed frequency then the band could be swamped in high use areas like cities. This is why the EU regulations limit fixed frequency (non-frequency hopping) 2.4GHz systems like DSM2 to very low power short range applications.
Frequency hopping systems like DSMX and most others don't have this same problem because they constantly jump (many times per second) between the 80 available frequencies. Even if you have 100+ users on line, the fact that you constantly jump frequencies means that for at least for most of the time you will find a clear frequency, so the system still works.
DSM2 uses two 'fixed' frequencies of the 80 that are available in the 2.4GHz band (the Tx actually selects two clear frequencies when it powers up). If you had 40 DSM2 users then the entire 2.4GHz frequency is fully 'swamped' and no one else could use 2.4GHz. The chance of 40 RC flyers all being in range at the same time is very slim but 2.4GHz is for a vast range of uses, not just RC. If they all used a DSM2 'type' system that used a fixed frequency then the band could be swamped in high use areas like cities. This is why the EU regulations limit fixed frequency (non-frequency hopping) 2.4GHz systems like DSM2 to very low power short range applications.
Frequency hopping systems like DSMX and most others don't have this same problem because they constantly jump (many times per second) between the 80 available frequencies. Even if you have 100+ users on line, the fact that you constantly jump frequencies means that for at least for most of the time you will find a clear frequency, so the system still works.