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Joined: 19 Feb 2003
Posts: 1
Location: Malaysia

Post Radio Reply with quote
I am a college student and just learned some new stuff for radio. I was just wondering how can i make a transmitter and the receiver unit (something like walkie talkie or ham unit) operating in an unlicensed airwave. What is the range of the unit. What if i wanted to do a unit that can transmit around 200-400km or maybe even more? I understand that is lies in the modulation and demodulation for it to travel further. So can anyone educates me more and provide me with some material to work on? circuit diagram,block diagram and the pcb diagram with the list of the materials wanted for the project. Thank you. And by the way, can a repeater be used for the signal in WiFi? I mean i got a PCMCIA wireless network card from DLINK DWL650 and got a friend lives quite far away using also wireless signal. Can i amplify the signal without disturbing other channels? just for plain Adhoc. not the Infrastructure.
Wed Feb 19, 2003 6:48 am View user's profile Send private message MSN Messenger ICQ Number

Post hope this helps Reply with quote
Update: The DWL-650 has newer variants (they no longer have the "axe-head" style antenna housing) that are *not* Intersil Prism based. Linux users beware: the dwl-650 version 2 uses the ADMtek chipset. Trust me, no amount of forcing any orinoco module will work with that card or any later version, go to ADMtek's site and download/compile/install the source. D-Link has changed the chipset on this card at least twice since version 1 without any change in the model number that is typically quoted by vendors.
Beware of buying the DWL-520 PCI card!

It has been described as a Prism II compatible card, but this same model number has three different incarnations.

The latest version of the DWL-520 uses the ADM8211 chipset (DWL-520c1, on the DLink web site, though you can't find those last two, magic letters, any where on the box or card).
beware with DWL-520 and ADM8211 (DWL-520c1), this chipset has a very bad receiver sensitivity. manual quotes rx-sens at -84dBm

For the output power part, go to the Radio -> configuration option. All the textboxes that come up are the power output for each channel. The highest output power (100mw supposedly) is at hex value 80, and as you change the value (in either direction) from 80, the power output drops linearly (so 7A and 86 are the same power output). These settings might also explain why out of the box, performance isn't the same on all channels (with ver 1.1 hardware, certain channels have lower output power by default, with ver 1 hardware, they're all the same)!
Tue Oct 07, 2003 11:07 am
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