Question/Trouble


#1

Hi All!!, I am having problems with my receiver because once or twice a day it gets deaf, it doesn´t hears any planes and I have to reset it. After reset, it starts working properly for about 12 or + hours, but then again gets deaf. The antenna is OK, as I`ve checked. Do you have any ideas about what it could be? Thanks in advance


#2

Make sure the USB receiver is being powered properly. Assuming you’re using a Raspberry Pi, make sure you’re using a decent power supply such as the official 2.5A PSU. If the memory card is quite old or a slow one, try a new fast one (Class 10). Just a couple of ideas.

Has it only just started doing this or has it always done it? What receiver is it?


#3

I’ve seen this on one of mine.
I checked the PSU and my USB voltmeter showed 5.15V
It seems the USB power plug interfered with the case and couldn’t be fully inserted.
I modified the plug slightly and now get a little more insertion depth. It’s been stable since.


#4

Just an FYI. The measurement should be made with the load connected. Also, it’s a good idea to measure current flow.


#5

Hi Dxista, what you say is correct …but …

It depends what you want to know (and what you already know)

For convenience, I use a cheap USB meter that is intended to be placed in series with the device you are testing which will also give you a current reading.
The trouble with these cheap meters is that they have a non-trivial shunt resistance which results in a significant voltage drop across the meter.
In this case, I use a multi-port 3500mA USB supply to power a Pi3b+RTL. I’m not particularly interested in the current (at this time), so I plug the meter into a second outlet and it tells me the voltage without becoming part of the circuit I’m testing.

So, yes I did have the Pi connected, but not though the meter.

Another point (you politely ignored) is that a $3 meter does not have 0.01V accuracy. As I’m sure you are aware, accuracy and precision are not the same thing.


#6

I did not ignore it, I simply missed the fact that you used a $3 USB voltmeter, sorry. I have one of those, and I consider it more of a display than a meter.

Fair enough, but it’s the current draw that drags the nominal voltage down.

If all is working as expected, this is basically an academic discussion then.


#7

Indeed! In my defense, I have checked it against a better meter and I’ll say ‘it’s good enough’ so long as you are aware of its limitations (ie. it probably won’t give you the same reading twice)

in my case it wasn’t. The input voltage measured ok, the Pi was powered up and reporting to FA, the LED in the RTL was lit, but after a time (30min to 12h), just as @gfcoria reported, the message count would drop to zero and stay there until the Pi was restarted.
My fix was to modify the USB plug so it was able to be fully inserted.