#20369: Xiaomi mini Wireless signal is very weak
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Reporter: rexchou | Owner: developers
Type: defect | Status: reopened
Priority: high | Milestone: Chaos Calmer 15.05
Component: kernel | Version: Trunk
Resolution: | Keywords:
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Comment (by anonymous):
comment from padavan on site:
http://4pda.ru/forum/index.php?showtopic=596689&st=4700
W) PA / LNA
Each chip has a WiFi radio transmitter and receiver. To send a signal it
must be reinforced through PowerAmplifier (PA) to the level of 20dBm
(100mW), the levels vary with the laws of each region. In some WiFi PA
chip is embedded in the device may be diluted with a built-like (iPA), and
external (ePA). External PA are always well received signal amplifier Low
Noise Amplifier (LNA), so if there is ePA, the circuit ePA / eLNA. If you
are using a built-iPA, it can be applied iLNA or external chip eLNA.
On a subject:
2.4 radio wired as iPA / eLNA + T / R switch
Radio 5 wired as iPA / iLNA (T / R switch and built-in)
When placed external chip LNA, the input from the WiFi chip should be
muted (normal gain LNA 12dB, depending on the characteristics of the
particular eLNA), otherwise the LNA will supply high level, which will be
distorted. For this purpose the EEPROM registers parameter "External LNA
Gain", which tells how much dB you need to reduce the sensitivity of the
input to which a signal from the LNA.
When using the internal LNA, it is common practice "External LNA Gain" is
not filled in, ie It is the nominal sensitivity. On sabzh factory in
EEPROM 5GHz hammered 2dB, it decreases the value of "hearing" at radio, ie
the worse the hearing, the worse the AP hearing the client at his disposal
and greatly reduces the speed of the link.
the last described is exactly what is happening on 2.4G wifi
--
Ticket URL: <https://dev.openwrt.org/ticket/20369#comment:50>
OpenWrt <http://openwrt.org>
Opensource Wireless Router Technology
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