i did not plan to mix them, that is why i bought 2 of each.
but when i search for them i saw that the dsm2 is cheaper then dsmx i thought that it might had some thing to do with the signal lost or some thing on the dsm2 sats, and i coud see in the specs of the tx that it can run with the bouth of them, so i choose the cheap one's for the 450 bird