Grounding the Maestro

EA4GLI

Have quite a bit of electric noise being captured by the Maestro. The interesting thing is that the same noise I see in the panadapter on the Maestro is not there when I connect with the computer. The other interesting part is that any time I touch the metal knobs on the Maestro the panadapter visual noise decreases considerably. If I operate with the USB battery its much better but it is still there.

The PSU that came with the Maestro is not usable for me... it produces a ton of noise... chances are the ground prong in the outlet is not really grounded. 

I am using the same PSU I use with the Flex radio and there is definitely some grounding issue... so I was wondering... is there any recommended spot to ground the Maestro?

Chris DL5NAM

Salvador, how you detect the PSU noise at Maestro? In Audio ?
Maestro is a user panel/interface no receiver. I use the MeanWell PSU from FlexRadio. No problem with Maestro or any other TRX here in shack.

73 Chris

EA4GLI

Video.
Check the PSU that came with the Maestro

https://www.youtube.com/watch?v=J2HW4nvtKJ4

Granted that it could probably work better with proper grounding in my house... so I am not putting all the blame on the PSU, but it is there.

Chris DL5NAM

Yes, i see and understand. Will check and compare here too. 

Chris DL5NAM

Salvador, i can see also here. Not so strong like yours. If i connect PSU i see also a light sinus wave.
I change to other and stronger PSU: problem is gone!!!!  So it's the MeanWell .
If i found time i will check the MW what current the Maestro take and with Scope the voltage 

EA4GLI

I am pretty sure it is on my end.... not a direct fault of the Maestro... but it is more sensitive to electric noise than operating with the computer and SmartSDR.

Here it is the effect of "grounding" the Maestro by touching.


https://www.youtube.com/watch?v=-eqJicSEuZE

EA4GLI

It is odd that the Maestro PSU produces so much "noise" in my case. Comes with a couple of toroids and it has ground in the wall plug...

This last video is with the Maestro connected to a 30Amp  PSU (powerwerx SS-30DV)

EA4GLI

One more thing. If I connect the ethernet cable the noise is almost completely gone.
So try with WiFi.
With WiFi and USB Battery also less noise... it is definitely getting the noise through the 12v plug.

Steve (N9SKM)

Sounds like good ol common mode noise to me. Same thing happens with the PSU that pro audio sells for the KX3 which actually is a very low noise supply. Put a few wraps around a ferrite and see if that helps.

EA4GLI

Around the power cable?

Steve K9ZW

Be suspect of that amp and proximity.  The PSU may well be acting as an antenna for amp noise.

I improved my main station by putting my Expert Amp on the floor.

Got much better when I repurposed the Expert (now have an Alpha-9500 where it was).

While every shack is different, based on my experience look carefully at the amp as a potential noise source though.

73

Steve K9ZW

Chris DL5NAM

Mainly at 12V - but at power cord also is never a fault

EA4GLI

Well, that fixed it, I have half a ferrite rod that broke... do not drop your ferrites... I just put 5 turns of the 12v power cable around the toroid and the common mode noise is gone. I just repurpose a broken ferrite that I though had no use whatsoever.

The surprising thing is that the same PSU is not throwing any of that noise into the Flex radio. 

I am going to try to add ferrites to the Maestro PSU to see if it makes a difference.

Thanks a bunch guys!!

EA4GLI

I have the 1k here in Barbados and have not had any noise issues, but I have the 1.3k in Spain and I had to move it around because I was getting RFI into the shack.

I will keep all of this things in mind.

Steve (N9SKM)

Pro audio has a good article on common mode noise. the PSU they supply is very low noise (they show plenty of tests and i have looked at it on a spectrum analyzer as well) but when you plug it into the rig i get more noise if im using my mag loop antenna. The mag loop is just much more susceptible to common mode noise in this instance. Ferrite on the power cable and noise is gone.

Steve K9ZW

My 1K wasn't so clean as yours. 

Great amps, but I understand these issues are not uncommon.

73

Steve K9ZW

Dietmar K

I'm wondering how a pure digital display can have grounding problems. If I understand correct, the MAESTRO displays the digital data received from the FLEX?!

Does the MAESTRO has any connection to the FLEX - STP lan cable, power cable? If so, I assume the FLEX itself is affected and not the MAESTRO?

//Dietmar

Steve (N9SKM)

Rf noise of any kind can effect circuits. digital or analog. what is most likely happening is that the power to the maestro is coupling noise into the radio itself that it is picking up on the antenna port. Or something in the maestro with his length of power cable is resonating. Rf in the shack can be a hard thing to track down sometimes, just the right length of cable that will pick up some random frequency and resonate is all it takes to put noise on something.

Someone with a spectrum analyzer can slap the PSU that came with the maestro on the probes and give us the skinny, But the fact that a ferrite fixed it it should be no factor now. There are infinite lengths of cables in shacks that can resonate, every once in a while you get unlucky.

EA4GLI

An update. The provided PSU will still produce the common mode noise in my shack even if I add a couple snap on ferrites on the cable.