From: Dan Halperin <address@hidden>
To: Bill Stevenson <address@hidden>
Cc: address@hidden
Sent: Wednesday, November 5, 2008 1:08:41 PM
Subject: Re: [Discuss-gnuradio] a simple qustion about the attenuator for the SMA cable
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On Nov 4, 2008, at 2:31 PM, Bill Stevenson wrote:
> I have a rudimentary question about the attenuator. When I was searching some questions in the archive, I found that some guys mentioned when testing the transmitter and receiver for daughter board, the antenna should be connect by Tx/Rx SMA, the Tx and Rx can NOT be connected directly by cable and we need a attenuator about 40-50 dB!! What is the meaning of attenuator here? Is it a hardware? Thanks a lot for all!
An attenuator is a piece of hardware that weakens ("attenuate" means weaken) the power of a signal transmitted along a wire. When you directly wire a TX board to an RX board, the power transmitted is much stronger than receiver expects (even a tiny bit of air gap induces a lot of attenuation) and can fry the circuitry. So we simulate this air gap with an attenuator.
Fixed RF attenuators can be had for fairly cheap
($10-20) I think.
- -Dan
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Hello, Dan
I got it!Thank you so much! But I think we could also attenuate the transmitted power by
setting --tx-amplitude to a reasonable value. Do you think so? What's your idea?
Thank you!
Bill