Re: [Discuss-gnuradio] RFX2400 Jamming

[Jeremy Chew]

Hi, here is an update:

I have tried transferring the RFX2400 (rev 30) from the new USRP 4.2 to an 
USRP 4.1. Now there seems to be no radiation at all when 2.44GHz is chosen, 
even with GR and ping working. It appears that IP tunneling starts up with 
no problem though.

Is there something I am supposed to do to set up the RFX2400 before starting 
to use it? (I have yet to get any application working with it.) In any case, 
how do I reset the programming on the transceiver board/USRP?

(NB: The noise floor mentioned below is more like -90 to -100dB.)

Thanks,
Jeremy

----- Original Message ----- 
From: "Jeremy Chew" <address@hidden>
To: <address@hidden>
Cc: "Harry Han" <address@hidden>
Sent: Tuesday, April 10, 2007 7:37 PM
Subject: [Discuss-gnuradio] RFX2400 Jamming


> Hi,
>
> I am not sure if others like Syed Shah may be having the same problem, but 
> I notice similar symptoms as he has with my new RFX2400s I got just last 
> month.
>
> With a spectrum analyser, I notice that with just switching on the 
> RFX2400, there is continuous radiation from the radio at frequencies I 
> have set before on the radio. The signals are measured at about -70dB 
> to -75dB approximately 20-30cm from the transceiver antenna, regardless 
> whether GNU Radio (GR) software or the PCs are turned on. The noise floor 
> is -80dB.
>
> Later, when the IP tunneling example is run without MAC, the signal at the 
> frequency selected for the example, 2.44GHz, goes to noise floor level. 
> However, once the ping application starts periodic transmissions, the RF 
> radiation at 2.44GHz rises to about -72dB and remains there continuously, 
> even after ping or GR are turned off. Not surprisingly, no ping packet 
> gets through.
>
> This does not happen with the RFX400s I have used. The software is the 
> same in both cases except for the frequency setting.
>
> I am using GNU Radio 2.8 as I had problems building GR3.0.x. In any case, 
> my application works with GR2.8 and the RFX400.
>
> Thanks,
> Jeremy
>
>
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