Amplitude over reading?

[Andy]

Hello. I have an SA44b and it is over-reading amplitude by approx 2dB. This seems to have started when I installed Spike version 22, although I am not sure of this.
An input of (say) -10dBm from my Marconi 2024 signal generator reads only -8dBm and the same 2dB error is displayed at all amplitudes and frequencies and all RBW’s.
I have tried attenuators just in case there was some kind of mismatch going on, but the error is always the same. I have also run exactly the same test on my Rigol 1030atg analyser with accurate results.
I have removed and re-installed Spike, but this has not made any difference. Any ideas please?

[Andrew]

Hi Andy,

So, currently, I have been unable to duplicate this with my SA44B, but I may be using a setup where it doesn’t appear. If you could provide me with a specific setup, I could try to duplicate this.

Also, if you think it is version specific, here is a link to the 3.0.21 software.
signalhound.com/sigdownloads/Spike/Spike(x64)_3021.zip
I would interested to know if this resolves your issue.

If this doesn’t work, email support at signalhound dot com with your serial number and we can send you the cal files for your device, in the event the current ones on your system got corrupted.

I look forward to your response.

Regards,
A.J.

• This reply was modified 10 years, 7 months ago by Andrew.
• This reply was modified 10 years, 7 months ago by Andrew.

[Andy]

Hi AJ.
Here’s the setup, but it happens in any setup:

CF: 401 MHz
Span: 2 MHz
RBW: 30 KHz
VBW: 30 KHz
REF: -10dBm

Input level from signal generator: -40 dBm, also at all other levels.
It’s late here, so I’ll try the 21 software tomorrow. Many thanks for the prompt attention.
Andy.

[Author]

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