Factors affecting IR range?

[Mog]

Having spent hours hand-crafting a protocol using P8/740
direct calls, I was really pleased when I was able to
successfuly control my new device !

BUT, (there always has to be a but), I find that when I
move from my wifes chair to my own, I can no longer
control the device - no reaction whatsoever

So what are the main factors that affect the range at which
IR control will work?

In this instance, all is fine from 6 feet, but not from 10 feet,
using the device upgrade in my Topline.

The original remote works fine from 10 feet, as do the codes learned
in my Kameleon.

I have recorded the output of my Topline on the Kameleon, and am
pretty happy with the results - the timings match up pretty well,
with those recorded from the original equipment remote.

I'm guessing factors may be:
Pulse timings, battery condition, duty cycle - are there others,
and which are the most significant?

It's pretty frustrating, having got this close, and now to get
this problem!

[mr_d_p_gumby]

So what are the main factors that affect the range at which
IR control will work?

1) Carrier frequency. The IR reciever in the equipment is tuned to a specific frequency, and if you are off somewhat, it will not be as sensitive.

2) Pulse widths. The decoder in the equipment doesn't see the exact pulse timing that is transmitted, but rather it sees the demodulated signal that the IR receiver sends to it. The IR receiver can output varying pulse widths depending on the strength of the signal it receives, and it sounds like the pulse widths start to get out of bounds beyond 6 feet in your case. This might be because they are not quite correct yet.

Overall, I would try to get your pulse widths on the P8/740 even closer to the OEM remote, if you can. It sounds like you are close.