Mike, Our last project we used two IRF-6s with different addresses and two Ts per IRF-6. We also had a fifth T2 for IR operation only. Starting with the IR unit and working back, all programming and operation went flawlessly until the second T2 on the second IRF-6. No matter what I did I could not get reliable operation via RF. I swtiched the programming with the single T2 in IR mode and the new remote worked just great. The T2 unit with the problem RF worked just fine in IR. I programed the *troublesome* T2 to the other IRF-6 and had the same problem.
In my case it seems to be the T2 in RF mode that was the problem: range was not the issue. All other units worked at distances and conditions that I thought they should not(44+ feet, two concrete lathe and plaster walls, antenna and IRF-6 near/on TV and equipment) with standard issue antennae.
I agree with Pat that fully extending the antenna wire helps for reliability.
