[landlord11]

Hi, I recently installed dd-wrt on a TRENDnet TEW-828DRU. I tried a few builds and am currently on 30880. Unlike others I had no trouble installing and upgrading.

I noticed an odd issue monitoring the signal strength on the 5GHZ band. I was sitting directly next to the unit while testing, so there was no obstruction. When set to the lowest channel I get a nice strong signal, but as I move the unit to higher channels the signal strength and SNR decline. For example, I might see >95% strength at channel 36 but only 60% strength at channel 149. SNR declines as well. Has anyone else ever seen this?

I tried playing around with transmit power but didn't have any success.

I'm running the unit as an AP with WAN disabled and am only using wl0 and wl1.

Thank you!

Brian

[Per Yngve Berg]

It can be limitations with the Regulatory Domain.

[landlord11]

Thanks for the reply. I have my regulatory domain set to US, and have also tried Canada. My understanding is both domains should allow the same output for low and high channels. For example, channel 36 and 157.

But I'm seeing these signal strengths (using 40 MHz bands)

36: 90%
44: 88%
52: 80%
60: 74%
100: 62%
108: 60%
116: 53%
124: 60%
132: 60%
149: 60%
157: 55%

It is also much lower power than output by Apple Airport units I have (I get better signal through my difficult walls from Airports across the various 5GHz channels). Given I can reach much higher output levels at channel 36 I assume the hardware is capable and the limitation is software. But it doesn't match the expected behavior of these regulatory domains.

So I feel like there is something limiting output power in addition to the regulatory domain.

[mac913]

It's the regulatory domain that controls power output with depends on Country & Channel used. These power settings are part of the closed code of the WiFi drivers that DDWRT has no control over, plus it keeps DDWRT legal; well that's my take on it.

As for your comparing Apple Airport to the latest DDWRT firmware. It's not apples to apples comparison :) The newer drivers in DDWRT will have updated Country Regulatory then the Apple Airpot. I true comparison would be to use the same WiFi Driver dates on both units. Or using a DDWRT firmware dated then same or earlier than the firmware date of the Apple Airport would be a better test.

[landlord11]

Hi, so in the interim I picked up a Netgear 6700. I installed the same dd-wrt version, 30880, and set to the same regulatory domain (United States). The Netgear outputs full power on channel 157 while the 828-DRU does not. So something appears to be wrong with dd-wrt on the 828-DRU.

[Per Yngve Berg]

The CFE is also part of the tx power limitstion.

How did it oerform with stock fw?

[landlord11]

I didn't notice any issues, but wasn't paying as close attention at the time and don't know if I was on a similarly high channel. I'll need to flash back to stock to test conclusively. Which I'm happy to do; is there anything I need to be aware of when reverting? I.e. Is there a specific process to follow, or meerely flash the old firmware via dd-wrt's firmware upgrade interface?