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My recently purchased SA Ultra shows 5GHz WiFi signals on 4.4GHz (no sign of them between 5 and 6GHz) and the harmonics of my 2.5GHz (max) signal generator also appear to be low in frequency, The 2.5GHz fundamental is shown as being on the correct frequency. I do not have a signal source that will go any higher than 2.5GHz, only the WiFi of my dual band (2.4 and 5GHz) router.

I have not seen a mention of these issues, is the real upper frequency limit more like 3GHz, as opposed to the 5.3GHz printed on the case?

Thanks for your thoughts.

73 Dave G4AON

Wifi signals are broadband and, as you have read in the Ultra wiki page before unlocking Ultra, these can appear on different frequencies because the Ultra mode can get confused by broadband signals.

Here a single 5GHz signal

The low frequency spurs are generator by the signal generator.

And here a 2.5GHz signal with the second harmonic at 5GHz

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And in case you are concerned about high frequencies have a look at this topic:?/g/tinysa/topic/95874590#8980
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On Thu, Mar 23, 2023 at 11:35 AM, G4AON wrote:

My recently purchased SA Ultra shows 5GHz WiFi signals on 4.4GHz

Hi Dave,

I've checked my TinySA Ultra with a GPS locked signal generator and it was only 1.2kHz off frequency at 10GHz. However it does get confused by some types of signal, especially those using digital modulation such as spread spectrum and TDMA.

Can you see your WiFi correctly on 2.5GHz (within the 3GHz 'normal' mode) ?

I find it quite difficult to find the best settings to observe it, but it's not impossible.

The sweep time and RBW settings are fairly critical.

Maybe try that before 5GHz and Ultra mode? ?

Regards,

Martin

Hello Martin (and Erik). Thanks for the prompt replies. Yes, 2.4GHz WiFi shows easily, what puzzled me was the 5GHz WiFi not appearing at all, or at least not between 5 and 6GHz.

I have no particular use for anything higher than perhaps the 3rd harmonic of 23cms (3 x 1296MHz), but was slightly concerned that I couldn’t see even a hint of the 5GHz WiFi.

Dave G4AON

On Thu, Mar 23, 2023 at 07:12 AM, G4AON wrote:

...., 2.4GHz WiFi shows easily, what puzzled me was the 5GHz WiFi not appearing at all, or at least not between 5 and 6GHz.

?The antenna supplied with the tinySA ultra was primarily chosen for the normal mode (100kHz-800MHz) and not the Ultra mode.? The antenna performs reasonably well at 2.4GHz, but not at 5GHz. An antenna designed for 5GHz will allow you to observe 5GHz Wi-Fi signals but you will still need to lower the tinySA Ultra's noise floor to get a good signal-to-noise ratio. See the following figures that use the multi-band feature to show the 2.4 and 5GHz Wi-Fi bands side by side.

Using the antenna supplied with the tinySA Ultra and default RBW setting, only the 2.4GHz WiFi band signal is perceptible.


Using the antenna supplied with the tinySA Ultra and a 100kHz RBW plus enabling the LNA makes the 2.4GHz WiFi band signals more distinct, but the 5GHz Wi-Fi band signals are still not?perceptible.


Using a 2?GHz to 11 GHz Log Periodic?pcb antenna by WA5VJB?and a 100kHz RBW plus enabling the LNA makes both the 2.4GHz WiFi band and 5GHz Wi-Fi band signals perceptible.? The LNA is a SPF5043Z which is only specified to 4GHz, so an external pre-amplifier rated to 6GHz would give you a better signal-to-noise ratio when measuring 5GHz Wi-Fi band signals.


Herb