Episode 536c The TinySA needs to have low input levels to keep mixer harmonics low. If used in this range the performance is quite good Be a Patron: / imsaiguy
I wonder why they went back to the smaller form factor and didn't go straight to the 4" version display. May have to do with manufacturing lead times but I'd buy one in a heartbeat with the larger screen. Having said that for $50 to be able to put it in your pocket ain't bad! Thanks for the review!
@bobblacka918
2 жыл бұрын
In order to avoid any front-end overload problems and to protect the TinySA from accidental static discharge, I acquired a pair of lab grade 10 dB SMA attenuators which I leave permanently attached to both inputs. You might wonder why 10 dB and not 20 or 30 dB. Because 10 dB should be sufficient to absorb any accidental discharge and it only reduces the dynamic range of the TinySA by 10 dB. This is makes it easy to do the math so if I read -40 dBm on the screen I know the actual signal is at -30 dBm. In the event I do need the full dynamic range of the device for small signal analysis, it only takes a few seconds to remove the attenuators. But having both attenuators constantly protecting the front-end of the TinySA gives me peace of mind that I won't accidently burn out this amazing and useful device from an accidental static discharge event.
@NeilMaron
3 жыл бұрын
Thanks for updating your criticism. It makes me feel more comfortable about the tinySA.
@okjames4658
2 жыл бұрын
It's important to note that the 8920 series is a communication test set, with a spec A function, not really fully representative of the HP Spec A's of that vintage. That said, price/performance of the Tiny is great. But with any Spec A, you have to be aware of it's capability and how you are setting it up, to ensure best measurements. It's easy to measure the instrument misconfigured, and think it's your DUT.
@rogeronslow1498
4 жыл бұрын
It's called intermodulation distortion.
@loubraga5800
3 жыл бұрын
Excellent, as always
@AECRADIO1
4 жыл бұрын
RBW harmonics from MCU @ 48 MHz. TCXO @ 30 MHz. Good results, thanks for the update. Looks like a better choice. What is the highest frequency you have tested the device at?
@IMSAIGuy
4 жыл бұрын
960MHz
@fredschader7372
4 жыл бұрын
You should have mentioned the difference from the peak of the signal to the peak of the spur. It appears that the noise floor on the HP is higher and thus hides the spur implying that the HP is better.
@mpsmith35
3 жыл бұрын
I was going to point this out too. The TinySA is outperforming the HP analyser by at least 10dB!
@Slartibartfas042
4 жыл бұрын
Where is the indentatin on the three peaks coming from? On the HP analyser it clearly shows pointy and clear kind of spikes whereas the TinySA seems to produce some kind of plateau like an oscilloscope with first overshooting after quick rise and then ringing? (And, yes - of course we are in frequency domain with the TinySA, not in time domain)
@IMSAIGuy
4 жыл бұрын
I believe it is the shape of the IF filters. They are software DSP filters and can have an odd shape.
@Slartibartfas042
4 жыл бұрын
@@IMSAIGuy Hmmm... probably true. When I think longer of it that must be exactly what comes out if you transscript timedomain "ringing" problem of a scope into frequency domain. Input compensation of Scope equals IF filters with spectrum analyser. Maybe if the bin size (or bin count?) can be changed that effect may be corrected?
@Slartibartfas042
4 жыл бұрын
lol - I see exactly that filter curve on the tinySA Webpage. Maybe something that could be fixed with next firmware version for the resolution filters...
@okjames4658
2 жыл бұрын
I look at that filter shape and it would lead me to think there's a problem with the DUT. Kinda crappy filter shape, but dropping the span and tightening up the RBW would be my first thought on a swept tuned Spec A. Since the Tiny isn't, I wonder what the best solution is to determine if that modulation shape is real or an instrument artifact?
@H3liosphan
4 жыл бұрын
Interesting. So if you have a piece of radio kit you want to test that you can't control the power, how would you go about attenuating (is that right?) down to -30dbm so you can make real use of the TinySA?
@IMSAIGuy
4 жыл бұрын
I will be making a video about that in the future but you need to get an attenuator. The specification needs to be: dB (about of attenuation) Watts (amount the attenuator can dissipate) so to test a 1 watt transmitter: 1 watt is +30dBm. so you need a total of 60dB of attenuation to get -30dBm. You will need an attenuator rated for 1watt. 100watts is +50dBm
@IMSAIGuy
4 жыл бұрын
so 80dB needed and 100watt attenuators are not cheap
@IMSAIGuy
4 жыл бұрын
you can also use a dummy load with an RF sniffer.
@АндрейДенисюк-ш7п
4 жыл бұрын
It could be 20db 100W followed by 60db 1W, correct?
@IMSAIGuy
4 жыл бұрын
@@АндрейДенисюк-ш7п yes
@marcinsp5iou66
2 жыл бұрын
Thank You for good testing. Which version of TinySA is under this test? Old one o.1 - 350MHz or the newest one 0.1 - 960MHz? Probably firmware is also different / better.
@IMSAIGuy
2 жыл бұрын
latest model and firmware as of the date of the video
@marcinsp5iou66
2 жыл бұрын
@@IMSAIGuy Thank You. I've just ordered Tiny SA.
@amirb715
4 жыл бұрын
so why can't you just increase the attenuator setting? like 30dB. then with 0dBm input you get -30dBm at mixer. what am I missing here?
@IMSAIGuy
4 жыл бұрын
yes, you are correct. you need to make sure that happens though and it is not automatic
@ErikKaashoek
4 жыл бұрын
When you compare harmonics it maybe is good to ensure the noise floor is on the same level otherwise you will see the harmonics in one SA and they are hidden in the noise floor on the other SA.
@IMSAIGuy
4 жыл бұрын
@@ErikKaashoek yes that is true. I struggle with the display. the number of vertical divisions are not the same on the two instruments. the noise floor is pretty close between the two but does change depending on RBW which I cannot control on the HP instrument it is always automatic and usually ends up being more narrow than the Tiny
@herbertwalker2442
4 жыл бұрын
@@IMSAIGuy You also didn't mention that in your previous video you didn't perform a level calibration, and therefore, your measurements were off by almost 3dB. In this video your tinySA was calibrated (reference level text is white instead of red) and your measurements matched the HP within .5dB. Although the tinySA can't do some automatic level adjustments that the HP can, you have to judge that against its $50 cost versus that of the HP. What the tinySA does do is if you calibrate it properly and the reference level text is white, when you approach its overload level the text will turn red to warn you that you might want to back off.
@IMSAIGuy
4 жыл бұрын
@@ErikKaashoek People are already confused about the calibration and comparing it to the NanoVNA. How often to calibrate? do you need to calibrate for each start/stop frequency change?
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