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Electronics => RF, Microwave, Ham Radio => Topic started by: harrimansat on October 20, 2024, 06:12:34 pm

Title: SA6 spectrum analyzer without rf shield
Post by: harrimansat on October 20, 2024, 06:12:34 pm

There is anaone with a cheap aliepress SA6 spectrum analyzer? I have just received one and is quite noise. I have taken it apart and I see that it does  not have RF shield for receiver and generator. If anyone has the same unit can please make the same meassurement that I upload? There´s not signal on SMA input.

Thanks

Title: Re: SA6 spectrum analyzer without rf shield
Post by: harrimansat on October 20, 2024, 08:24:16 pm

https://youtu.be/OXHJ6RjT8s8?si=mBr-HzrJrk_xXu83

Title: Re: SA6 spectrum analyzer without rf shield
Post by: Kean on October 20, 2024, 08:42:36 pm

Without anything connected to the input you are still going to pick up ambient radio signals.

Try again with a 50 ohm terminator on the input.

Title: Re: SA6 spectrum analyzer without rf shield
Post by: KE5FX on October 20, 2024, 09:27:13 pm

What you actually wanted was a TinySA Ultra.  The Zeenko store on Ali Express sells the legitimate ones, I believe.

Title: Re: SA6 spectrum analyzer without rf shield
Post by: harrimansat on October 21, 2024, 08:19:47 am

I have one too! and other real spectrum analyzers, Thanks!

Title: Re: SA6 spectrum analyzer without rf shield
Post by: harrimansat on October 21, 2024, 08:21:46 am

Thanks for your answer Kean, but this thing has low impeadance inputs. Any way you can see the same results with a 50 ohms termination.

Title: Re: SA6 spectrum analyzer without rf shield
Post by: electronic_guy on October 21, 2024, 10:53:23 am

Usually the input is 50 ohms. And even after connecting the 50 ohm termination, you get these spurious signals and they are considerably larger, then it’s probably originated internally and that’s not a good sign. It could be problem with the LO, mixer, power supply issue and/or many more.  It’s also possible that without good shielding it couples external noise. No SA is perfect so there are known spurious signals that will appear on the spectrum, but these are usually noted on the documentations by the manufacturer. I recommend you return it and get your money back if it’s possible.

Title: Re: SA6 spectrum analyzer without rf shield
Post by: harrimansat on October 26, 2024, 11:09:33 am

some more photos

Title: Re: SA6 spectrum analyzer without rf shield
Post by: harrimansat on October 26, 2024, 07:45:59 pm

Improved floor noise with custom made shield, 27.5mm x 24mm x 3mm