High power long range WiFi USB adapter

22 Aug 2009
Posted by Laptop Junction

Alfa USB 500mw Wifi Adapter Awus036hWith the arrival of the DELL Optiplex Sx280 ultra small desktop the Senao 100mW WiFi card is replaced by more powerful WiFi hardware. In 5 years the wireless network industry released new WiFi standards and produced hardware with more capabilities. The old Senao 802.11B  100 mW PCMCIA card is replaced by a Alfa Network 802.11 B/G 500 mW USB connected WiFi client. Here's a bit about both WiFi adapters, WiFi antenna's and a short performance review.


WIFI High Power Access PointsWIFI how to stay connectedWIFI repeater extender booster



Alfa Network 500 mW WiFi USB Adapter

The AWUS036H Alfa Network 802.11ABG 500 mW (27 dBm +/- 1dBm) USB card comes in a small plastic box with a peculiar flat shape. It has a green activity LED on top and a RP-SMA antenna jack on the business end. The AWUS036H Alfa Adapter comes with a small antenna. The AWUS036H small plastic casing is less suitable for bigger antenna's or cable. The extra long antenna that came as a gift was so long it dwarfed the tiny box requiring an extra mount to prevent it from falling from the table.

Long Range Alfa Network WiFi USB Adapter Realtek RTL8187L.
  USB 2.0 Alfa Network Long Range WiFi Adapter

Inside the AWUS036H the Realtek 8187L chip makes stuff work. The PCB looks rather simple with two 8 pin peripheral chips with markings 1554-P032-3E1 (probably RF related) and ATMHL8-46D-1-Z8H371 (most likely flash memory).

Realtek RTL8187L WIFI USB Chipset
The AWUS036H Alpha Network chipset - RTL8187L and two yet unknown chips.

WiFi antenna's for the road

Antenna's are everything - a good antenna increases the chance of finding WiFi signals where others fail. The Senao 802.11B 100 mW PCMCIA card lasted for years because of the antennas installed in the Machine.

WiFi omnidirectional antennas. Indoor window-surface-mount, outdoor with magnetic mount
Left: Outdoor omni-directional WiFi antenna with magnetic mount - Right: Pig-tail window Antenna

The antenna's that came with the AWUS036H pictured with the retired Senao OEM PCMCIA WiFi card.

RP-SMA Omnidirectional indoor WiFi Antennas
AWUS036H Omni-directional indoor WiFi Antennas with RP-SMA jack

The large RP-SMA antenna is simply too big for the small AWUS036H casing.


AWUS036H Drivers, Manual and Realtek Wireless Utility

The Realtek website lists drivers for Windows (Vista, Xp, WinCE, Win98), Unix (Linux 2.4/2.6 and Debian 3.1) and Mac (Tiger, Panther). There are no links to documentation or source files available. The mini CD in the AWUS036H package comes with all OS drivers, manual and a Realtek Wireless LAN Utility (RtWLan 402.2006.1.18 - January 2006) for Windows. Without driver installation a Windows XP SP2 system automatically recognizes the AWUS036H Alfa Network WiFi adapter.
WiFi Security wise the AWUS036H Alfa Network WiFi adapter has 64/128-bit WEP, WPA (TKIP with IEEE 802.1x), AES capability.

WiFi performance Alfa Network 500 mW USB Adapter

First experiences with the AWUS036H Alfa Network WiFi adapter are quite good. The AWUS036H managed to connect to an outdoor 54G WiFi Access Point over a distance of about 1500 feet (460 meter) through dense wet forest. The reported link quality was low and the connection was set at 1 Mbps (128Kb/sec).

Far much better than the Senao 2511CD which couldn't connect at all using the same antenna and required a WIFI repeater / Range Extender. Over this large distance without line of sight the WiFi connection performed reasonably well with download speeds averaging round 17Kb/sec (0.132 Mbps). A window surface mount pig tail antenna connects the AWUS036H with the outside world through a 3 meter coaxial wire.

The advertised 500 mW (27 dBm +/- 1dBm) remains an unverified claim/ The maximum power specification for a USB2.0 port is 500mA @ 5 volts. At least the current (Amps) necessary to create 500mW transmission power @ 2.4 Ghz should be there - however WIFI transmission power depends on the WIFI mode (B/G) which in this case was 54G.



Senao 100 mW WiFi PCMCIA card

Senao produced the 2511CD Plus EXT2 802.11B - 100 mW PCMCIA card in early 2000 and competed with the popular Orinico WiFi adapters from Proxim as a cheaper alternative. The Senao 2511CD uses the Intersil Prism 2.5 chipset. Most WiFi adapters back then came in either (mini)PCI or PCMCIA (Cardbus) flavor. Nowadays USB connected WiFi adapters have become quite popular because it allows more flexibility where to place the adapter hardware and antenna.

Senao Prism PCMCIA WiFi Adapter 2511 CD PLUS EXT2

mmcx plug jack senao wifi pcmcia card

The downside of the Senao WiFi card are the 2 sensitive MMCX antenna jacks mounted on the side. These jacks are not made for frequent use and wear out easily. Also some laptop designs have PCMCIA slots that go too deep which makes it impossible to connect a MMCX antenna plug. In all the Senao 802.11B  100 mW PCMCIA card never failed during 3,5+ years on the road.