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V3 receive noise

WildBill
 

I¡¯ve had nothing but problems with my radio in the maybe 3-4 hours I¡¯ve used it since new. First the tx died and I had to replace a few smt resistors to repair and now the receive has horrendous noise. When I first boot it up the noise floor is good but it becomes bad within 30 or so seconds. I tried running with a battery with identical results. ?Anyone else have this amount of noise on theirs?


so far it¡¯s been a poor investment.
WildBill
 

I guess I¡¯ll cut my losses and part it out. I can always use another raspberry pi.?
 

Contact support for a solution.
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Gyula HA3HZ
WildBill
 

What support?
 

Try this.? Put a .1uf bypass cap on the small voltage regulator board, pin 4 to ground. It is the ENABLE port on the board. Pin 4 is the pin next? to the large electrolytic cap on the main board next to the header for the regulator.
 

I haven't had your particular issue, but if it is the full sbitx, seek a warranty solution first. Please contact sales, support. After that, this forum has some very knowledgeable hams who can assist with troubleshooting. The biggest challenge you might have is diagnosing if you are experiencing a hardware issue or a software issue. Most functions and features are handled by software in this radio. Ashhar and JJ have been very helpful to me in those cases. I suspect,? the first chore they, or others assisting will recommend, will be to save the files specific to your unit, download replacement software,? and see if the problem persists. Save photos of software versions, write down everything with as much detail as possible for your correspondence.? Noise is often caused by a bad filter capacitor or voltage regulator. If you have a good oscilloscope and voltmeter handy, that can be checked, after pursuing a warranty solution. Don't give up yet. Please keep us posted.

73
Scotty WD4PYT?

On Thu, May 30, 2024, 8:49 PM WildBill via <Km6q=[email protected]> wrote:

I¡¯ve had nothing but problems with my radio in the maybe 3-4 hours I¡¯ve used it since new. First the tx died and I had to replace a few smt resistors to repair and now the receive has horrendous noise. When I first boot it up the noise floor is good but it becomes bad within 30 or so seconds. I tried running with a battery with identical results.? Anyone else have this amount of noise on theirs?


so far it¡¯s been a poor investment.
 

Good, then I'll guess: you bought it from another radio amateur. In this case, do not contact HF Signals support.
Sorry to interrupt your monologue.
--
Gyula HA3HZ
WildBill
 

I bought it new from Gigaparts. I thought this item didn¡¯t have a warranty so I fixed the transmit issue that it had when I received the unit myself.?
WildBill
 

No scope. Best I can do is measure ripple voltage with DVM? I¡¯ll try that soon.
WildBill
 

But filter caps are necessary when using AC power, I tried with my dc power supply and also ran it on battery.
 

Sir, what is happening, I think, is that the voltage regulator is oscillating due to the ENABLE pin floating. By bypassing that line will keep the regulator from crating noise.? That noise is getting on the 5 volt bus. I had the same problem at first and the bypass cap cured most but not all of MY noise. Worth a try.
Barry
 

Barry talks about pulling the EN leg up to Vin through a 100k resistor as described. Details can be read in the pictures.
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Gyula HA3HZ
 

Wasn't it solved by replacing the 5V stabilizer?
 

If my information is correct, this sealed box contains the same circuit that is installed here. The difference is that the metal box shields the 150 kHz. Since the box cannot be opened without destroying it, identification is not easy. If someone sacrifices a piece and unwraps it, we know more. It follows from the pricing that the closed Drock buck converter is increased by the price of the metal housing and mass.
Hopefully the EN pin is boosted to Vin with a 100k resistor, as the IC documentation refers to.
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Gyula HA3HZ
 

I replaced my 5V regulator($1) with the new DROK($13) one.? I took a lot of pictures and posted them here on the forum.

It did lower the noise floor.? But, the noise floor of my radio really wasn't bad to start with.? So, it was a nice improvement/modification but by no means a repair.

The noise you are getting isn't normal.??But, in the video I noticed even your ICOM sounded kind of rough in the background.? Is it possible you are picking up some strong noise from the house?? The reason I say that is sometimes when I'm charging my electric car close to where I'm using my sBitx I'll get noise up and down all of the bands.? And of course, I see it go away as soon as I disconnect my charger.? ?The charger noise will show up even with the antenna disconnected.? But, the car and the radio probably aren't 6ft apart.? Most radios you would expect to go full quieting with no antenna hooked up.? My FT-DX10 never picked up the charger noise even with an antenna.? But, my sBitx will pickup really strong electrical noise like a car charger?even without an antenna.??

Is it possible to run your radio on 12V and cut power to your house?? Or run the radio on 12 volts somewhere else?? Not, saying that is it.? ?Maybe, only a slight chance. But, I would want to know if it's a local noise source before I dug deeper.
 

If the noise comes in through the power supply line, you can do a noise filter by passing the DC line through an FT140-43 ferrite core. By forming 6 threads from the wire on the ferrite core. I have a 2.5 mm2 power cable.
This acts as a choke against external disturbances. I have seen a similar solution on several websites.
When I used the v2 software and had various malfunctions, I did it, but not because of the noise.
I looked for the cause of the malfunction and also paid attention to the grounding at one point.
It's worth a try to make the noise smaller.
The picture shows that it is connected via an XT60 connector, so it can be removed if it doesn't work.
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Gyula HA3HZ
 

Cool idea on how you did that! Thank you for the pointer.

Scotty WD4PYT?

On Wed, Jun 5, 2024, 2:49 AM HA3HZ via <gyula=[email protected]> wrote:
If the noise comes in through the power supply line, you can do a noise filter by passing the DC line through an FT140-43 ferrite core. By forming 6 threads from the wire on the ferrite core. I have a 2.5 mm2 power cable.
This acts as a choke against external disturbances. I have seen a similar solution on several websites.
When I used the v2 software and had various malfunctions, I did it, but not because of the noise.
I looked for the cause of the malfunction and also paid attention to the grounding at one point.
It's worth a try to make the noise smaller.
The picture shows that it is connected via an XT60 connector, so it can be removed if it doesn't work.
--
Gyula HA3HZ
 

I had a similar experience. My first sBitx failed after about 20 minutes of use, resulting in no transmit. ?I suspect thermal expansion of the circuit board from the very hot finals compromised some of the SMDs.?

The makers sent me a new sBitx. They seem eager to make my experience a good one. Kudos.

However, while the transmitter in the new one works--if very inefficiently*--my new receiver sounds like yours, especially in certain parts of the bands. The receiver on the first one worked properly and consistently.

The noise on 20 meters (around 14.100 MHz), 40 meters (around 7.050 MHz), and 80 meters (around 3.530 MHz) is so loud as to make the radio essentially unusable on these band segments. ?Closing and reopening the sBitx application occasionally results in better receiver performance. Sometimes the receiver doesn't work at all. ?Sometimes it emits a pulsing noise. ?

There is clearly something wrong with these radios as manufactured. ?I'll be contacting the makers again. ?

James Todd
WB0KWJ

*The radio consumes about ~60 watts on 80 meters to produce a 10-watt signal. ?More on 40 and 30. ?

?
WildBill
 

I do not see that board in my V3. Are you talking about the same radio?
WildBill
 

The 5 volt regulator gets very hot quickly and I think that is the reason for the high noise level as it starts to get noisy after running a few minutes. There is not much in the way of troubleshooting documents or test points on the board to help troubleshoot and no place to send it to be repaired. Guess I lost $400. Yep, I'm a little angry at that.

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