SBX TX/RX RX leakage

GNU Radio
1

Hi, guys, I am doing full duplex on SBX. Is there any leakage from TX
to RX? Is that much?

Best,
Gang

2

On 07 Feb 2013 11:31, gang li wrote:

Hi, guys, I am doing full
duplex on SBX. Is there any leakage from TX
to RX? Is that much?

Best,

Gang

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There’s roughly
40dB isolation TX/RX on these cards.

3

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

4

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?

5

On 02/08/2013 04:10 PM, gang li wrote:

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 L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium

6

Just put 50 Ohm dummy loads onto the connectors and check for a signal,
then
you see if it is leakage or not :slight_smile:

Ralph.

TX/RX and receiving on RX2 at the same time. When I put the antennas

energy leaked from TX to RX will dominate in the total received
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

7

Thanks for your reply. I dont have a dummy load in hand. Are there
any other ways to check that?

On Sat, Feb 9, 2013 at 2:35 AM, Ralph A. Schmid, dk5ras