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TOPIC: Antenna Input Crosstalk

Antenna Input Crosstalk 10 Mar 2020 18:35 #1

  • DL9NBJ
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Hi @ all
I have problems with crosstalk from antenna input A2 (HF) to A1 (2m).

When I looked at the spectrum at 2m, I was wondering where all the interference suddenly came from, when I found that the interference can only be seen if the antenna at the A2 input is not grounded.

Who still has these problems?

I have this effect from the beginning, unfortunately I have failed to take pictures. At the moment my SunSDR2DX is not set up at the remote location, it requires too much bandwidth for WLAN, I still have to install a Raspi with software. I also thought it would be a little easier.
vy 73 de Thilo DL9NBJ

Problems with my SunSDR2DX:

VOX - works only on 2m, not on HF
TUNE - does not work, reduces power when tuning if SWR is bad
Displayed supply voltage has incorrect values
Crosstalk betwen antenna ports A2 <-> A1
Solved: ... ;-(
Last Edit: 10 Mar 2020 18:35 by DL9NBJ.
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Antenna Input Crosstalk 10 Mar 2020 20:08 #2

  • EI9HEB
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In my case using 2m and 20m band at the same time is impossible.
The 20m band display 14Mhz but what im really receiving is 145Mhz
As an example, local 2m repeater 145762.500 on the right and the same signal on the left on 14.348
How do you VooDoo?
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Antenna Input Crosstalk 10 Mar 2020 21:48 #3

  • DL9NBJ
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Very impressive !
That means you have crosstalk from 2m to 20m, i didnt checked this direction until now.
Can you messure in db the Crosstalk level difference with an beacon or an Repeater signal?
Can you also approve crosstalk from 20m to 2m?

Thank you very much !
vy 73 de Thilo DL9NBJ

Problems with my SunSDR2DX:

VOX - works only on 2m, not on HF
TUNE - does not work, reduces power when tuning if SWR is bad
Displayed supply voltage has incorrect values
Crosstalk betwen antenna ports A2 <-> A1
Solved: ... ;-(
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Antenna Input Crosstalk 10 Mar 2020 22:14 #4

  • EI9HEB
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Look like it is exactly the same level on 20m than on 2m

When I record IQ files on 20m and play them back. The player shows 2m band.
So look like when 2m is selected on the main receiver the second receiver receive 2m band but display 20m.
This is not crosstalking it a bug :wall:
How do you VooDoo?
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Antenna Input Crosstalk 12 Mar 2020 16:03 #5

  • G4ENZ
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I don't think you are allowed to have one receiver above 80MHz and one below 80MHz. The ADC only runs at 160MHz. What you are seeing is an alias rather than crosstalk.

Martin G4ENZ
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Antenna Input Crosstalk 15 Mar 2020 00:36 #6

  • DL9NBJ
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Hi Martin

I only have one receiver active at a time. So far I have only noticed these effects at 2m because the band is so quiet there. It is immediately noticeable when strange signals appear. But it may be that these effects are within the normal and permitted range.
vy 73 de Thilo DL9NBJ

Problems with my SunSDR2DX:

VOX - works only on 2m, not on HF
TUNE - does not work, reduces power when tuning if SWR is bad
Displayed supply voltage has incorrect values
Crosstalk betwen antenna ports A2 <-> A1
Solved: ... ;-(
Last Edit: 15 Mar 2020 00:38 by DL9NBJ.
The administrator has disabled public write access.
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