Re: [Discuss-gnuradio] RFX400 Antenna Connection

[David Scaperoth]

what is the receive PGA set to?  I find it works best at the midpoint  
(35 or so).  you may want to simply scale back your transmit power  
with a multiplier block:

gr.multiply_const_cc(0.1)

I don't know exactly what the correct amount of attenuation is, but  
40dB sounds like enough (you'll have to wait for Matt or Eric on  
that).  one way to tell would be to use the usrp_fft.py and send a  
tone into the 400 board, then you could see what the power level is  
needed to get the signal in above the noise floor (i.e. strong enough  
for GNU Radio to see it).

how far away are the boards from each other?

hope this helps.

David


On Mar 5, 2007, at 5:53 AM, Jeremy Chew wrote:

> Hi,
>
> I am trying to eliminate channel error by using a cable to connect  
> two RFX400s together. The strange thing is that nothing useful  
> seems to get through when the radios are connected by cable. I have  
> tried attenuation in the range from 0 to 40dB and with several  
> cables to no avail. Using antennas works much better.
>
> Do you know what is wrong? And what should the cable attenuation be?
>
> Thanks,
> Jeremy
>
>
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