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Re: My tinySA has 10MHz internal interference

 

I also saw a signal of about the same level under the same operating conditions on my first run classic tiny. It could easily have been leakage from my 10 MHz GPSDO reference right below be in the basement lab.

On Wed, 16 Apr 2025 17:37:25 -0700
"Toni Ciscar via groups.io" <aciscar@...> wrote:

In my two tinySA ( original from Zeenko 2021 ) I can also appreciate something in 10 MHz by reducing the background noise by lowering the RBW , setting a scale of 2 dB / Div and fixing the measurement with a TRACE / CALC / AVER16. It's not a problem.
--

73

-Jim
NU0C
Re: My tinySA has 10MHz internal interference

 

In my two tinySA (original from Zeenko 2021) I can also appreciate something in 10 MHz by reducing the background noise by lowering the RBW, setting a scale of 2 dB/Div and fixing the measurement with a TRACE/CALC/AVER16. It's not a problem.
?
Re: My tinySA has 10MHz internal interference

 

Hi Dianzi,
?
I just checked my TinySA (the basic version), and I don¡¯t see anything at 10 MHz using your same setup regardless if spur removal is on or off. ?Also note my trace is very flat (no slope) and averages approximately -110 dBm using center frequency of 10 MHz and span of 2 MHz (no antenna connected and ports not terminated).
?
Just FYI,
Don
Re: My tinySA has 10MHz internal interference

 

Hi (how should I address you?)

What happens if you put 50 ohm terminators on the connectors?

Regards

Lou
VK3ALB


On Wed, Apr 16, 2025 at 3:39?AM dianzi via <jpf48162341=@groups.io> wrote:
Hi everyone, I have used my tinySA basic version for several years and it has passed the self-calibration. When I set the 10MHz test and connected nothing, it would appear in the spectrum. I have also ruled out the interference from my environment. Is this an internal circuit problem?
Re: My tinySA has 10MHz internal interference

 

Thank you for your feedback. You have the same problem. We probably have the same problem.
Re: My tinySA has 10MHz internal interference

 

Not a knockoff
Re: My tinySA has 10MHz internal interference

 

It goes away with Spur Removal in the Config menu.
Re: My tinySA has 10MHz internal interference

 

I remember I saw the same signal when checking some 10 MHz standards using the tinySA (basic)
It is very weak but still there. (nothing on the Ultra).
?
This is from my V0.3
?
Not a problem.
?
´¡²Ô»å°ù¨¦
Re: My tinySA has 10MHz internal interference

 

On Tue, Apr 15, 2025 at 10:38 AM, dianzi wrote:
Is this an internal circuit problem?
Where did you buy it?? Perhaps it is a clone.....
?
Roger
Re: My tinySA has 10MHz internal interference

 

I initialized it again and restored the initial value, showing -95dBm
Re: My tinySA has 10MHz internal interference

 

Hello,
I just checked my original TiySA like yours, not an ultra, and did not show any unknown signals like you posted.
I would remove the case and check the two shields to make sure they are in place and have not been dislargeed during use.
They are just just held in place with very small U clips.
Other than that, you may have a outside signal near you.
Clyde KC7BJE?
Re: My tinySA has 10MHz internal interference

 

I just checked my ULTRA.? I enabled the preamp and set it to span from 5 through 15 MHz.? I did not detect any spur at 10 MHz down to a reported -116 dBm.?

Dave - W?LEV

On Tue, Apr 15, 2025 at 5:38?PM dianzi via <jpf48162341=@groups.io> wrote:
Hi everyone, I have used my tinySA basic version for several years and it has passed the self-calibration. When I set the 10MHz test and connected nothing, it would appear in the spectrum. I have also ruled out the interference from my environment. Is this an internal circuit problem?



--
Dave - W?LEV
My tinySA has 10MHz internal interference

 

Hi everyone, I have used my tinySA basic version for several years and it has passed the self-calibration. When I set the 10MHz test and connected nothing, it would appear in the spectrum. I have also ruled out the interference from my environment. Is this an internal circuit problem?
Re: Auto Save Issues

 

I got everything to work as I wanted! Thank you again Erik! Your help was very much appreciated :)
Re: Operating Close to 7.3G and some NOOB RF/SpecAn Questions

 

The impact of the RBW on a power measure is relevant when the RBW is small with respect to the bandwidth of the signal, since only a piece of the signal is taken in each measurement. The formula:
Bandwidth Correction {dB} ?= 10log (CH BW/RBW)

Pt = P{dBm} measured + 10log (CH BW/RBW)
where CH BW is the bandwidth of the signal (AM, FM, nFM, QAM, etc.).
Re: Operating Close to 7.3G and some NOOB RF/SpecAn Questions

 

The tinySA can do channel power measurements. You can use a channel wide enough to capture all the spectral components and it will give you the total power.
--
Designer of the tinySA
For more info go to

Re: Operating Close to 7.3G and some NOOB RF/SpecAn Questions

 

It has to do with whether the IF bandwidth is sufficient to capture all of the spectral components, and also with the fact that the SA is calibrated to respond correctly to a CW signal, not power, although newer SAs have an RMS detector function.?
There is an additional adjustment which accounts for the different way in which the analyzer responds to noise(like) signals than to CW.
Here is a Keysight app note which goes into more detail: ?
?
There is also a need to compensate for CW signals in the presence of noise. When the signal is 10dB above the noise there is an approximate 0.4dB error due to the noise power being added to the CW signal; when the signal is equal to the noise there is a 3dB error.? I have a spreadsheet which takes as inputs the noise level and CW signal level and makes the correction as well as an article by Morris Engleson (who authored a very excellent book on spectrum analysis) explaining the calculation and its background.? Newer analyzers also have a similar noise correction routine.
?
Best regards, Don
?
?
Re: Operating Close to 7.3G and some NOOB RF/SpecAn Questions

 

Thanks for this Don,
?
so FM, nFM and AM will all have their power level impacted by a change to RBW, is there any formula for this ? Or is it a fairly minimal impact??

Or it is more to do with the ¡°Noise Like¡± nature of the signal, a CW is very uniform where these other types are more chaotic ??
?
Re: Operating Close to 7.3G and some NOOB RF/SpecAn Questions

 

That filter is the same I am using looking at our 6GHz STL, it works well.
?
John
Re: Operating Close to 7.3G and some NOOB RF/SpecAn Questions

 

The power level of a CW signal should remain the same with RBW changes.? Modulated signals (which are noise-like) and noise signals (like the baseline noise level) will change with RBW changes.
73, Don N2VGU
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