Maximum TX Transmit Power on DIR-615 D2 (Ralink)

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KrypteX
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PostPosted: Fri Feb 13, 2015 10:36    Post subject: Maximum TX Transmit Power on DIR-615 D2 (Ralink) Reply with quote
I'd like to know what is the real maximum TX Transmit Power for the Ralink-based DIR-615 D2 router (and/or the similar D1/D3/D4 and H1/H2 versions, all Ralink) ?

The product manual states 15 ± 2 dBm, which is roughly equal to 32 ± 18 mW. So the max value is 17dBm = 50mW.

DD-WRT sets a default 100 mW in recent builds, even though it used to be 71 mW in older ones (e.g. 23320).

So which one is it ? Is there anyone who knows if DD-WRT might damage the radio if run at 100mW for too long ? Can the radio handle 100mW, if the manual states an average 32mW (50mW max) ?

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js1662
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PostPosted: Sun Feb 15, 2015 0:00    Post subject: Reply with quote
According to Wikdevi, DIR615-H use RT3352 from Ralink for Wifi. I found the following product brief from the Internet for RT3352: https://wikidevi.com/files/Ralink/RT3352%20product%20brief.pdf

The Tx power as mentioned on the product brief is 16dBm so I believe setting it to 15dBm is about right. Since the transmitter is build in the RT3352, so it probably won't transmit a power higher than it can handle. Hence I guess it probably won't damage the chip if you set the power too high as I doubt it will output the higher power you want.

I would start at 15dBm setting and see how it works. Increase the power and see if it works better. If not, I will set it back to 15dBm.
KrypteX
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PostPosted: Sun Feb 15, 2015 7:53    Post subject: Reply with quote
Here's a short table of dBm-to-mW transformation:
Code:
14   dBm =  25 mW
15   dBm =  32 mW
16   dBm =  40 mW
17   dBm =  50 mW
18   dBm =  63 mW
18.5 dBm =  71 mW
19   dBm =  79 mW
20   dBm = 100 mW

So the factory spec is 16dBm = 40mW for the Ralink RT3352 chip. But I have a bit older chip on my DIR-615 D2, Ralink RT3052, with factory spec 14dBm = 25mW, which is much lower than the 100mW set by default on DD-WRT.
I've changed the Transmit power in DD-WRT on this router, and it accepts any value up to 120mW (I didn't check any further, because I wouldn't want to damage the chip). The Status page confirms the TX Power value.

I know others have gone up to 250mW, but that's 10 times higher than the 25mW from factory (if we are to believe the factory specs in the product briefs).
I remember older builds used 71mW, which still might be a bit high.

Is there anyone who knows which is the safest max transmit power handled by these Ralink chips (without burning out in the longterm) ?

_________________
THERE ARE NO STRANGERS HERE; ONLY FRIENDS YOU HAVEN'T YET MET.
____________________________________________________________________________
DD-WRT Links: BUILDS | SUPPORTED DEVICES | HOW TO RESET | TRAC | CHANGELOG

Atheros:
Netgear WNDR3800 ........ DD-WRT 29048
Netgear WNR2000v3 ....... DD-WRT 29048
TP-Link WA901NDv3 ....... DD-WRT 29048
TP-Link WR710Nv1 ......... DD-WRT 29048
TP-Link WR740Nv4 ......... DD-WRT 28493
Ralink:
D-Link DIR-615 D2 ......... DD-WRT 29048
Alozaros
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Joined: 16 Nov 2015
Posts: 123
Location: London,UK

PostPosted: Sat Dec 12, 2015 17:44    Post subject: Reply with quote
yep that is what i want I to know as well... ??
I also noticed and did some research and it seems it comes by default 100mW and its suggested 71mW so, even then its still over the limit according to the chipset ??

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D-Link DIR-615 H2 .........DD-WRT currently bricked after 28493
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D-link DIR-655.............. stock D-link FW (NAT,Guest AP)
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LOM
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PostPosted: Tue Dec 15, 2015 7:05    Post subject: Reply with quote
Read the FCC Test Report it states the "MAXIMUM PEAK OUTPUT POWER"
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