Re: [Discuss-gnuradio] why two switches and two Rx in RFX

[Jeffrey Karrels]

Message: 2
Date: Thu, 05 Jul 2007 10:10:15 -0700
From: Matt Ettus <address@hidden>
Subject: Re: [Discuss-gnuradio] why two switches and two Rx in RFX

...

> > I use two sets of USRP with RFX900 to test a FDD( frequency devision
> > duplex) by cable connection. According to my experience, the cable
> > loss should be less than 0.5-1 db, right? (which come with RFX900) So,
> > If I set the same gain for two RFX900 tx, say -a 100, the received
> > signal is much smaller than the coupled signal from itself, whatever
> > the different frenquency is. So, why there are both input signal? it
> > is coupled signal or intentionally designed? I think it is intentional
> designed, and since the tx signal is routed to Rx2 directly, so it is
> > much stronger than come from its peer end, is it right?
>
> You should NEVER connect the TX output to an RX input without a lot of
> attenuation in between.  You should also not be using RX2 in your situation.
>
> Matt

Question. What is "a lot of attenuation" (ballpark?)  I have a RFX1800
transmitting at "20" going into (cabled) a dbsrx with gain "40".
Between the transmitter and receiver I have 40dB worth of
attenuators... Would you suggest any different? I learnt the hard way
on the first dbsrx :)

Thanks
Jeff