[yo3fff]

Hi Andrew,

Is there any plans to implement this basic feature please?
I saw it for the phase measurements therefore I don’t understand why is not possible to have it for normal use of the spectrum analyzer.
By the way, this is a standard feature on your competitor Tektronix SignalVu.

Thank you.
BR,

Cristian

[yo3fff]

Hi Justin,

Thank you for the answer. The external attenuator it fix the problem.
Because the unit is not in the 1year guarantee I think I can fix it if you can send me the detailed rework to be applied.
I’m a professional Electronic Engineer being able to solder 0201 components.

Thank you for your support.
BR,

Cristian

[yo3fff]

Hi Andrew,

Thank you for the answer.
I try to evaluate what this analyzer measure with different detector types. I did 4 measurements with the analyzer’s input closed to 50ohm termination.
Here are the results:
Realtime_Det-Min_Max
Max Hold [dBm]= -122.98
AVG [dBm]= -130.93
delta [dB]= 7.95
——–
Sweep_Det-Min_Max
Max Hold [dBm]= -126.42
AVG [dBm]= -137.17
delta [dB]= 10.75
——–
Realtime_Det-AVG
Max Hold [dBm]= -128.66
AVG [dBm]= -134.14
delta [dB]= 5.48
——–
Sweep_Det-AVG
Max Hold [dBm]= -127.69
AVG [dBm]= -137.62
delta [dB]= 9.93
——–

As can be seen, there is big inconsistency between Sweep and Realtime Analysis Modes ranging between -0.97 to +6.24dB such as:
delta maxRT_Max-AVGRT_Max [dB]= 5.68
delta maxRT_AVG-AVGRT_AVG [dB]= 3.21

delta maxSW_Max-AVGSW_Max [dB]= 1.27
delta maxSW_AVG-AVGSW_AVG [dB]= 0.45
——–
delta maxRT_Max-maxSW_Max [dB]= 3.44
delta maxRT_AVG-maxSW_AVG [dB] 6.24
delta AVGRT_Max-AVGSW_Max [dB] -0.97
delta AVGRT_AVG-AVGSW_AVG [dB] 3.48

How can you explain this behavior?
From my perspective, one cannot use the analyzer for consistent measurements with different modes and detectors having more than 7dB tolerance.
In the specs the analyzer amplitude precision readings is less than 2dB so what is wrong?

Look forward hearing from you.
BR,

Cristin

[yo3fff]

Hi Andy,

Thanks for the advice. Problem solved.
I didn’t know that on the new version 3.1.x the ref. freq. should be adjusted.
For this, as Andrew mentioned, I’d used Utilities>Timebase Adjustment.

Thank you both of you!

BR,

Cristian Negru

[yo3fff]

Hi Andrew,
I’ve sent the same message to your support e-mail address together with Spike preint screens. I will attache two of theme here too.
Let me explain again the used setup measurement.
An RF generator was connected to SA44B input throught a 50ohm 6dB fixed attenuator. This hardware setup was not changed throughout the test! The RF generator was set to transmit a fixed unmodulated CW frequency. That frequency was 10MHz and 150MHz. I chose two frequencies to show that the frequency offset is not constant but increase with frequency!
Now, what was changend in the measurements was just the Spike software version! The hardware connection was keept unchanged. The RF generator is miniVNA PRO and have very good frequency stability (less than 10Hz/hour).
As can be seen from the attachement, with Spike ver. 3.0.19 the RF signal has a sharp 10.000000MHz and with the latest Spike ver. 3.1.18, the same RF carrier was read as 10.001773MHz. Somehow the new version add about 1.773kHz to the real frequency and this is even worst as the frequency increase.

Also from the att. you can see that RBW=VBW and are the same for both versions (30Hz). The analisys mode was Sweep measurement without spurious rejection. Ans yes, I put the marker 1 just to be clear the frequency reading. I use the peak search function which is working well.
I think you missunderstood the problem! There is NO hardware frequency offset. So how can I verify the frequency offset with different software version?

Please let me know if now is clear.
If you need more information, please let me know.

Thank you for support.

BR,

Cristian Negru

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[yo3fff]

Hi Andrew,

Thank you for the answer. My SA44B look almost the same. I don’t understand what are those spurs around 500-800MHz?!
Do you have in your future plans to normalize the overall noise floor?
Like measure it then mathematically extract it from the measurements the display it just to look linear.

In a 100kHz-100MHz span with RBW/VBW 6.5kHz and -60dBm ref. the noise floor was about -115dBm average. For this BW the thermal noise at 300K is -136dBm. That means that the overall analyzer’s noise contribution is 21dB?

Thank you.

BR,

Cristian

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[yo3fff]

Hi Andrew,

That is a good news I can export the recorded screens in CSV format.
I’ll try that.

Thank you.

BR,
Cristian

[yo3fff]

Hi Andrew,

This is a good news. At least I can visualize something.

Is there a chance to convert that binary or just to extract the spectrum from it (three dimensional table with time, frequency and amplitude) to a txt or other simple formats? Its not suppose to be that complicated if I know its structure, I guess.

Thank you.

BR,
Cristian

[yo3fff]

Hi Andrew,

Thank you for replaying to my post.
I want to save the spectrum at least one time per second (better 10 times per sec.). CSV has the advantage of being easy to use in different applications.

In my case I want to save automatically the sweep spectrum on a time scheduled and/or event triggered (like if the average amplitude will exceed a certain threshold).
For example, I want to record a 200MHz spectrum during one day to see what is an interference behavior like.

I’m not aware if I can do this with the recorder’s aid. And if it can do, how I get the recorded data in a general format in order to be analyzed with a different program (like Matlab)?

Thank you.

BR,
Cristian

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