[USRP-users] [Discuss-gnuradio] SBX TX/RX RX leakage

gang li blant.lee at gmail.com
Fri Feb 8 17:47:14 EST 2013

Yes. I am doing full duplex on the same frequency, transmitting from
TX/RX and receiving on RX2 at the same time. When I put the antennas
far way from each other, the received signal amplitude is very low.
And when I change the distance between them, i found the received
signal amplitude is kind of stable. So i think maybe the leakage takes
the major. Am I right?

On Fri, Feb 8, 2013 at 4:26 PM, Marcus D. Leech <mleech at ripnet.com> wrote:
> On 02/08/2013 04:10 PM, gang li wrote:
>> When the signal received on RF2 port has a very weak strength, the
>> energy leaked from TX to RX will dominate in the total received
>> energy. I have observed this in my experiments. Are there any ways to
>> measure the leaked signal so i can compensate it? I am thinking a way
>> of by connecting the RF1 and RF2 ports with a long cable and 60db
>> attenuators. And then i record the received signal. I assume it is the
>> leaked signal from TX. Are there any better ways? Thanks for your
>> reply.
>> Best,
>> Gang
> Are you TX/RX on the same frequency, or different frequencies?
> The usual way to deal with this on different-frequency setups is to use a
> duplexor, or a deep notch filter on the RX port, and probably boost your
>   antenna signal a bit with an external amplifier.
> But if this is *same-frequency* duplex, the on-board leakage is really minor
> compared to the coupling between your antennae.
> --
> Marcus Leech
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org

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