Firmware after 374.43 (with TX power from 0-100%) drops in dbm strength

[N66uASUS]

tested 374.43 (fork), 374.43 (merlin), latest stock 376.3602, and latest merlin 376.49.

firmwares after 374.43 will have a slider from 0-100%.
374.43 and older will have a number box with 0-200.

signal strength dbm gain is highest with default settings on 374.43 (fork) and (merlin).
i checked with inssider.

on 374.43, dbm gain goes down to -45
while on other firmware, its around -50-53.

why is that?

also tx power dont seem to make a difference after 80. but i can see difference if i reduce to 10 tx power.
if 10 tx power = -65 dbm.
80 tx power = -45 dbm.
100 tx power = -45

200 and 500 tx power still -45 dbm.

why newer firmware makes dbm signal strength weaker? (even at 100% tx power)?

 

[ColinTaylor]

It probably varies from router to router and firmware version to firmware version. But in 374.43 (merlin) on the N66U for example, the power appears to be applied in bands as follows (for both 2.4GHz and 5GHz) [see router/rc/sysdeps/init-broadcom.c]

<20mW
<40mw
<70mW
<80mW
=80mW
>80mW

Add to this the fact that depending on your region the higher power settings might be capped (typically at 80mW)

I haven't looked at any of the other firmware versions so the banding might be different for them.

UPDATE: I've just had a quick look at the current merlin code (376.49_4), just the N66U part. The banding appears to be the same although the code that allows >80mW has been removed. So 80mW (2.4GHz and 5GHz) is now the maximum irrespective of region.

See here: http://forums.smallnetbuilder.com/showthread.php?t=18762 for one of many threads about this.

 

[kvic]

I believe 80mW in 374.x branch never meant to be 80mW (way more than that actually. So one reviewer on Amazon was so amazed by AC56U's performance at 80mW!).

Also the GUI slider in 376.x branch of firmware never gets arithmetic right. If i were you, I would always keep it at 100% and never touch the slider or changing the % from the GUI.

Always go with nvram setting changes if you want to fine tune tx power. Not the GUI nvram values but "maxp2ga" and "maxp5ga"

The GUI is pretty but not functional. Speaking on my experience with AC56U.