Re: [Discuss-gnuradio] High packet error and reception problems with RFX 2400

[David Scaperoth]

On Apr 3, 2007, at 4:12 PM, Syed Faisal Shah wrote:

> Hi fellows,
>
> We just purchased USRP from Ettus equipped with daughter board RFX  
> 2400. We are trying to test these boards and have following problems:
>
> 1. The benchmark_tx.py and benchmark_rx.py from the GNU radio tar  
> ball 3.0.3 gave close to 100% packet error. During the experiment,  
> we used the maximum gain for receiver antenna and maximum amplitude  
> for transmitter.  We are transmitting wirelessly using different  
> settings of center frequency from 2400 to 2475MHz and bit rate of  
> 50k to 500kbps. We are using vertical antenna from Ettus for this  
> band. We varied the distance between the tx and rx from few  
> centimeters to 1m. At 1m, the receiver was unable to receive/decode  
> any of the packets at at all. Similarly at low bit rates, the rx  
> wan unable to receive/decode any of the packets. We appreciate any  
> help or clue to this problem.

Have you tried wiring the radios together with SMA (and 40dB  
attenuation)?  If nothing else, this should work flawlessly before  
you move on to wireless experiments.

What was the signal strength when you had the two boards a few  
centimeters from each other?  Just curious, What was the maximum gain  
you used for the transmitter (i.e. how did you set it?)  Another  
variable in this problem could be the setting on the Rx PGA.  Have  
you modified this value?  Most people have reported success at half  
of maximum.


> 2. We tried to use usrp_siggen.py and usrp_oscope.py programs to  
> transmit/receive a sinusoidal signal. The oscilloscope program did  
> show a sinusoid wave but the amplitude is weak and noisy. Even the  
> response to the orientation and distance of the transmitter is  
> random. For some orientation of the transmitter the received signal  
> gets better for a moment and then goes down again.

What was the gain you used (-g option) for the usrp_siggen.py?  Have  
you tried using SMA cables?

> Have anyone experienced this issue with RFX daughter board and  
> vertical antenna? Any help will be highly appreciated.

For what its worth, the RFX400 / RFX900 seem to work well with  
vertical antenna, and I don't see why the 2400 wouldn't either.


> Regards
>
> SFAS
>
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