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TOPIC: RFI/Ground Loop Problem or SunSDR2DX shielding problem

RFI/Ground Loop Problem or SunSDR2DX shielding problem 14 Mar 2020 09:54 #1

  • HA5OLA
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Hi,
I am struggling with a big problem with my SunSDR2DX, I always use MON function, but couple weeks ago I switched off and to my big surprise I still hear myself back on my headset on 20/1715/12 meters. I started with the usual remedies:
1.) Grounding: I put a 2m ground-rod under my radioroom in my garage into ground (I have a car service pit wihout foundtation in my garage) grounding wire in 4 sqmm. and 11m long- still same RFI
2.) 1:1 Choke baluns: everywhere! one balun at antenna feedpoint, another after Sunsdr another after tuner - still same RFI
3.) Antenna: I was confident that my Hexbeam is making this issue, so change to a 2 elem 20/17/15/12/10 Prosistel Yagi  - still same RFI

What is also troubling me that when I had the SunSDR2Pro I did not experience such issues. Also if I tune on 15m I many times get "Maximum output message", also if I drive my Acom 600s amp I usually need 20-22W to reach 600W out, buton 15m (21mhz) I only need 5-7W to reach 600W - very strange.

I use Heil Proset-6 headset - the same I used on Sunsdr2Pro. And I use LDG AT-1000ProII tuner.
Also my tower is not so far from my radio room so I can "backfire" on myself, but still there were no problems with Sunsdr2pro.

Any ideas?
73!
Robert
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RFI/Ground Loop Problem or SunSDR2DX shielding problem 15 Mar 2020 00:23 #2

  • DL9NBJ
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I keep getting these errors "Maximum output message

My question would be, how do you hear yourself back?
Crystal clear or distorted?

It could also come from the Windows settings.
Please check mic settings, see picture


xxx.png
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 00:30 by DL9NBJ.
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RFI/Ground Loop Problem or SunSDR2DX shielding problem 15 Mar 2020 08:49 #3

  • HA5OLA
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Dear OM Thilo,

The sound is what I hear is distorted so its typical RFI .
BTW in Windows 10 I can not find the settings what you mention BUT I do not use PC microphone.

To be honest my problem is that it is only happening with Sunsdr2 if I use my Icom which is 15cms from Sunsdr2 there is no RFI.
Still, my antenna is close to my house so I suspect Shielding, Grounding problem of Sunsdr2.
Strange because it is grounded.

73! Robert
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RFI/Ground Loop Problem or SunSDR2DX shielding problem 16 Mar 2020 07:59 #4

  • Rome
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HI, Robert.
Did you try to use ferrite beads on the antenna output of the TRX? We always recommend to use them.

We'll be checking SS2DX operation with an external tuner this week and will fix the firmware if necessary.
Роман, Roman
Expert Electronics
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RFI/Ground Loop Problem or SunSDR2DX shielding problem 16 Mar 2020 08:28 #5

  • HA5OLA
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Hi,

Yes I have ferrite beads everywhere (power supply cable, GPS, PTT microphone etc.). I know its seems ridiculous but I bought a box of ferrite beads and cores and wherever I saw a cable I put it on (even on rotor cable). Also for feedline I have put a Diamond CMF2000 1:1 choke ferrite balun right after SUNSDR2 and between the Amplifier than another between Amp and tuner than another after tuner plus balun at Yagi center.
My problem: that I tested yesterday my Icom 7100 again at it shows no problem. Could I somehow improve shielding of the Sunsdr2?

73!

HA5OLA Robert
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