Maestro noise problem

LA9AKA

My first post here, I'm kind of desperate for help to solve my Maestro issue. 


I bought a new Flex 6600 and a Maestro direct from FRS back in August. It was a breeze to set up and use, but I soon realized I had a problem with my Maestro. When connecting the Maestro everything worked fine for a few minutes, but then a "motorboating" sound gradually came along, starting out very low in volume, reaching a peak, for then again to go away in the same manner. The motorboating sounds a little bit like FSK441. When the noise is at its peak, the Maestro is unusable. I cant even hear extremely strong stations with volume up high. 

I first thought this was a network problem, looked at my network stats and they show minimal packet loss and excellent connection via WiFi. Tried direct connection to the switch, problem is still the same. 

I then realized I could turn the AF volume all the way down, and the noise is still there. I can even transmit, tune the antenna or change bands. The noise is there no matter what I do. Searched the forums here, but there was no similar problems to be found. Made a trouble ticket to Flex and they said I had to ship the Maestro to their EU service center in Germany. 

Norbert at Flex in Germany was very helpful and he had the Maestro in use for several weeks with no issues what so ever. The only thing I had not sent in was the original PSU, so he suspected it to be faulty. The Maestro arrived back to my QTH again, and the noise was present after 10 seconds of use. This was using the original PSU, so I connected it to a linear 13,8V PSU and was sure the problem was solved. But no, noise is still there. Next up Norbert suggested I connect the Maestro directly to my 6600, but no joy, problem still occurs. 

Last suggestion was that I should try to turn off my 6600 when the noise was present to see if the noise came from the radio itself. Tried this, but the noise was still there after the radio was disconnected. 

There is also another problem, I can listen to a very clear, rich sounding signal. Then it suddenly becomes distorted and sounds very thin with really bad audio quality. This problem also comes and goes, and can be fixed by restarting the Maestro. Often this problem comes just before this motorboating sound, but not always. Settings like AGC-T has no influence here. 

So basically I'm totally lost now what to do... I'm having a brand new Maestro that I can't use. This is not a complaint against Flex support, they have so far handled my problem well, but I would sure like to hear from other users ideas about what to try to resolve the issue.

I have filmed and captured the noise at several occasions and sent to Norbert at Flex EU.  

I need to add that using SmartSDR on my PC or the IOS app, everything works really well with no issues. 

To clarify; the noise comes out of the Maestro internal speaker. I will try connecting a headphone next time I'm in the shack and the noise appears.The noise is sometimes very loud, and sometimes barely audible. It varies a lot. It sometimes occur a few seconds after turning the Maestro on, and sometimes after 20 minutes. But for most of the time it shows up within a minute or two. Then it goes through uneven cycles as long as the Maestro is powered on. 

Any ideas? 


73 
Hans Christian LA9AKA 

Duane_AC5AA

What happens if you turn off the Maestro internal speaker and listen instead to a powered speaker connected to the 6600?  And headphones connected to the 6600?

LA9AKA

Duane, thank you so much for your input! 

As I wrote above, I have not tried headphones on my Maestro. And I have not tried what you suggest, headphones or a powered speaker on the 6600. I will give it a try just to see, but as far as I know I have isolated the problem to the Maestro. Since the noise is there even when I turn off my 6600. I will get back with my results later this week.

HCampbell WB4IVF

Since Flex/Germany used your Maestro for weeks without any problem, I suspect the problem may well lie outside the Maestro.  Have you tried using the Maestro/6600 (directly connected with new cable and another PS) at a different location, just to make sure that the Maestro is not somehow picking up locally generated noise? 

Howard

LA9AKA

Howard, thank you for your input! I agree, the noise can of course come from an outside source affecting the Maestro. I just cant imagine what could be causing this interference. I only have a few houses nearby, noise levels in general are pretty good. No other transmitters even remotely close. I will first try to bring my Maestro someplace else and connect via WiFi and see what happens. If noise occurs still, I will bring my 6600 and Maestro to a friend to see if the noise disappear. 

HCampbell WB4IVF

Also, you might try shutting off your circuit breakers and running the Maestro/6600 from a battery to rule out interference being generated by other devices within your own home.  

Steve K9ZW

Hi Hans Christian

Was wondering if you're using the Maestro wireless or cabled?  

I imagine everything is up to date on versions?

With the noise being there whether your radio is on or not, yet not being evident while in for repairs, you have a bit of a head-scratcher going there.  

Do you get any benefit on putting torroids on the cables if you are wired?

GL & 73

Steve
K9ZW

LA9AKA

I will try to do so! But I find it weird that I do not hear any of this RFI on any ham or broadcast band. No indication what so ever on the panadapter on any band... 

LA9AKA

Steve, yes this is a head-scratcher for sure. I'm using 3.1.8 now, problem was the same on earlier versions. I have tried both WiFi and wired ethernet, and of course a direct connection to the 6600. The only cable connected at the moment is the one from the PSU, I will try to use some mix31 torroids on it. But as I said to the gentleman above you here in the thread; I can't see any sign of this so called RFI on any band. 

NR4O

I recently noticed a very low level high pitch ‘whine’ coming from my Maestro speaker.  You can only hear it when there is no received signal.  I disconnected the external power and ran on the internal battery I have installed.  The noise was not present.  The noise was coming from my station DC power supply line.  I wrapped several turns of the power cord through a small 1 inch sized toroid and that seems to have cured the problem.  
You may want to try running on battery power to eliminate noise coupling from your DC power source.

Eric - NR4O

HCampbell WB4IVF

Using a battery is a great way to narrow down the source of RFI.  And RFI problems don’t always show up on spectrum displays. 

For example, a few years back I installed an Icom 7000 in my Accord including a noise filter at the battery.  All seemed to go well, but when I started the engine I heard noise which didn’t show on the spectrum display.  Obviously noise from the engine electronics, but surprisingly disconnecting the antenna cable and using a portable battery did not seem to affect it at all.  After some testing, the culprit turned out to be the cable from the 7000 external video display port to the 7” TFT monitor which picked up and apparently injected the noise into a later stage in the radio.  A new high-quality shielded cable solved the problem. 

When you turned off the radio and found that the noise was still present on the Maestro, did you also turn off the radio PS or was the radio PS still on? 

Let us know the results of your tests.  I’m curious how this unfolds.

Howard

Steve K9ZW

@Hans Christian - what happens when the Maestro is away from your shack?

As you mentioned it doesn't make a difference if the radio is on, would it worthwhile to take your Maestro someplace else and turn it on - even better operating remote - to see if the noise continues?

Quickly rereading things I'm wondering if the noise continues when you run your Maestro on a battery back?

You do seem to have interesting situation.  

GL & 73

Steve
K9ZW

Blog:  http://k9zw.wordpress.com  

LA9AKA

Gentlemen, thank you so much for your input! I've had very little time lately to experiment with the Maestro, I emailed back an forth with Norbert at Flex EU service center, and he says that it is highly unlikely that RFI is causing my problems. If there was RFI powerfull enough to interfere with the Maestro, my 6600 would be affected long before the Maestro. 

So Norbert ordered a pickup of my Maestro from UPS and there would be no cost for me shipping it to Germany this time. Great I thought... But right now, I must say that I am not a happy camper. This UPS pickup thing was handled extremely poorly both by UPS and Flex EU. The Maestro is still not on it's way, and I need to pay for some of the shipping. I am pretty frustrated to say it the least. 

I will keep you posted about what the end of this story will be. 

73
Hans Christian LA9AKA

LA9AKA

Steve, I was supposed to do this, but I was not able to get it done before Norbert at Flex EU service center ordered a pickup of my Maestro by UPS. He said that it was highly unlikely that RFI is causing this. I will keep you posted what his findings are later on. 

Thank you, and 73
Hans Christian LA9AKA