Increasing power of transmitter

Discussion in 'HyperWRT Firmware' started by vulcan4d, Jan 3, 2005.

  1. vulcan4d

    vulcan4d Network Guru Member

    I got the linksys wrt54G to replace my BEFW11S4 B just plainly because I could upgrade to the hyperwrt firmware, which allows to increase the power of the transmitter. That way if I knew I would need more range, I could adjust it easily.

    So I got my wrt54g and immediately I noticed a weaker signal, at a test range of just 5ft away. I go by what XP tells me, have no idea what to make of netstumpler as there is no description of what the values mean. So anyway I get a "very good" signal at 5ft. My B router resulted in an "excellent" signal. So I didn't care much since I knew the hyperwrt firmware allows to increase the power.

    I flashed my router, setup and checked it, still "very good" at the default 42mW. Kinda odd since I read the default for the official firmware is just 19mW. Just for the heck of it, I set it to 21mW and the result was "low". Hmm, interesting. Set it to 53mW which is suppose to be the highest strengh without increasing noise, but still "very good". Set it to 84mW and finally the signal was "excellent". At only 5ft distance, I'm suprised at the poor signal strength =(.

    I'm using the same usb wi-fi B adapter for these tests as I had with my B router. Antennas were setup exactly in the same way. Is this normal for the G router?
  2. thikrat

    thikrat Network Guru Member

    I had something similar to this happen. I changed the antenna powert to 53 mw and i noticed two things... if i received a call on my cordless line before the firmware upgrade, the wireless internet would drop 75% of the time.... but now, its only about 20% of the time. However, it appears that my signal does the same thing the previos poster mentioned.

    Sometimes it just hovers around very good and 18 mbps.... is this normal? or am i just looking too deep into it?

  3. vulcan4d

    vulcan4d Network Guru Member

    Well I went and exchanged it and this one is pretty much the same. Guess it's how these G routers are. I said pretty much because this one 40% of the time comes up with an "excellent" signal. Using that netstumpler, the SNR value keeps jumping from 30-50. At 30 it says very good and at 50 it's excellent. Not sure why it fluctuates like this, the noise level is at a constant -92/93...whatever that stands for ^^. Anyway I should finally get my G usb pen adapters coming in soon, wonder how they'll pick up the signal.
  4. Poisonsnak

    Poisonsnak Network Guru Member

    The -92 is probably in dBm units, to convert to mW you use:

    Pd = 10*log(Pm/1mW)

    Where Pd is the power in dBm and Pm is the power in mW. The reverse formula may be more helpful:

    Pm = 10^(Pd/10)

    Also the SNR would be the difference between the signal and noise (hence the name hehe), even an SNR of 30 is pretty good imo that would put your signal level at -62dBm. My SNR around the house is more like 10 or 20 and I have no issues even with cordless phones. Maybe consider some 900MHz models? The WRT54GS operates at 2.4GHz.
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