Have procured two separate limesdr-USBs and both fail LimeQuickTest, looking for advice

Projects LimeSDR
1

Both the LimeSDR-USBs that I have ordered in the past year have failed the LimeQuickTest. The output shown below, is for the LimeSDR which was procured to replace the other LimeSDR which was found to be faulty (Haven’t done anything other than run LimeQuick Test). At this point I cannot tell if it is something I am doing when testing with LimeQuickTest, or if I am just being sent bad boards. Looking for advice on how to proceed.

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2

If you do not use CH1 on 1.8GHz it is fine. Error margin is very small (only 2dB).

3

I guess, I just would expect a product out of the box to be fully functional.

4

Did you have any coax connected to the board?

Ed

5

No, it is in the aluminum case it came with and I have not attached any antennas or wires to the RF ports.

6

Any ideas?

7

I think it is meant as no coax connected to the board.

Ed

8

It does, nothing at all connected to the RF ports and the board should be cold.

This is not a hard failure, the margin is very small and you may find that in certain conditions it passes.

9

The project I am working on has the LimeSDR operating in the UHF amateur band. Do you think given the LimeQuickTest Output that there would be any performance degradation in that band? (I know the failure is in the 1800MHz band, just wondering if this is a sign of other potential hardware faults)

10

The test is only valid for a cold board,

Part of the test result, that you omitted shows the temperature e.g. “Chip temperature: 27 C”. So if your board had been powered on for more than lets say a minute there is the potential that the elevated temperature (especially during summertime) could be the cause. That it is only 0.7dB above a pass would make me think that temperature is probably the cause.

Provided there is cooling I do not think that there would be any issue with continuous operation on the 23 or 70 centimeter amateur bands (with external filtering, if it is being used for TX).

11

Thanks for input. I am planning to test with cold board on Monday. I believe when I ran the test the board temperature was somewhere in the 40-60 C range.