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DSE New Zealand XH6825 500mW 2.4GHz Bidirectional Amplifier

A little while back there was a heads-up and ensuing discussion on the Melbourne Wireless mailing list about a 500mW 802.11b/g amplifier that Dick Smith New Zealand sells. Well I bought one. This is the item in question:
External link

I ordered it in early February and received a customer code from the website but no email confirmation. After a month I just assumed that the order didn't go through. Then on 10th March it arrived. The invoice is interesting as it appears I haven't been charged NZ GST on the item, even though the "tax code" says that I have. I paid NZ$264 for it, which is AUS$240. I also bought a 7dBi magnetic mount antenna (which I now strongly suspect to be a 5dBi antenna) for NZ$40.89 and postage was NZ$25.11. The grand total was AUS$298 charged to my credit card.

The Amp has a RP-SMA connector on the antenna side and a standard-SMA connector on the radio side. Included is a SMA-to-RP-SMA RG-316 pigtail so you can plug the amp into your AP. The Amp runs on a 6V DC supply - don't know what the current draw is though. The manual claims a 17dB increase in transmit gain and a 10dB increase in receive gain. Interestingly, the Longreach 1 watt amp claims a 15dB increase in transmit gain and a 16.5 increase in receive gain. Refer to PowerAndGainToDecibels.

I've been putting the amp through it's paces, and have compared it to my External linkLongreach 1 watt amp.

I have a External linkSuperpass 8dBi omni on top of a 13 metre mast at my node - Node GMR. It was connected to a SVEC AP inside my house, and I used to have the Longreach amp inline - in locally powered mode. I shelled into Node GES and ran Wavemon. He has a 13.5 metre mast with a 25dB conifer on it pointed at me. We run on Channel 4.

Here are the Figures from Node GES

Link Quality 54/92 80/92 78/92
Signal Level (dBm) -66 -53 -55
Noise Level (dBm) -100 -100 -100
Signal-Noise Ratio (dB) +34 +47 +45

I now use a Minitar as my AP, here are the figures with the DSE Amp inline:

Link Quality 78/92
Signal Level (dBm) -53 (dips into -52)
Noise Level (dBm) -100
Signal-Noise Ratio (dB) +47 (dips into +48)

As a control I also ran my laptop in my office with an Enterasys card (using the internal antenna) and ran External linkKnoppix STD on it. Here are the Wavemon figures:

Link Quality 20/92 28/92 27/92
Signal Level (dBm) -75 -65 -66
Noise Level (dBm) -93 -92 -91
Signal-Noise Ratio (dB) +15 +27 +25

These figures from my office are a bit rubbery because I was sitting right next to the laptop and there was a lot of fluctuation. I did stare at the screen for a long time however and wrote down the most stable figures.

I don't have a SMA-to-N-type pigtail yet so I can't plug the amp into any of my cards. So I have yet to run wavemon on an interface that actually has the amp plugged into it. I plan on doing so soon so I can get a good idea of the noise figure of the DSE amp.

Any other suggestions for testing? -- DanFlett 170304

Update: 03/09/2006 On the subject of these Dick Smith Amps.
I (another mw member), bought one an amp that looks (and its specs) are exactly as the dse one.
There obtainable for around $130-$160 from citytechnology.com.au and have a brand name of micro-beam

Version 7 (current) modified Tue, 03 Jul 2007 23:11:57 +1000 by steve
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