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Re: Wideband spurious signal?

 

Thanks David and Erik.
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I find cell tower signals that look similar in lower frequency ranges, that are plausible cell tower signals, e.g. LTE band 1 downlink (20 MHz):
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They also match the german frequency plan:
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The signal i've mentioned in the 8.56 GHz range is one of the strongest signal i can find on the whole range up to 9 GHz (even stronger than the local FM radio tower), see here:
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Another signal around 7.5 Ghz is also very strong. I've now attached an 6dB attenuator to be sure to not blow out the LNA.
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Comparing the LTE signal with the 8.56 GHz signal, i find it looks very similar. The bandwidth is just higher with 60 MHz vs. the 20 MHz LTE signal.
So it doesn't seem to be a mirror of another signal in the lower ranges, because i can't find anything with the same bandwidth and/or power.
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I find it very odd, because in the frequency plan, the only signal in the 8400 to 8500 MHz range is "permanent radio service", which sounds plausible.
The thing is, the signal goes from 8.47 GHz to 8.53 GHz - so it overlaps.
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I monitored the signal (late evening into the night), and to me, it doesn't look like a cell tower signal:
The signal suddenly stops in the middle of the day for some time, and the power level drops abruptly going into the night.
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Comparing that to a real LTE signal (band 20), the difference can be seen:
Gradual power level changes over time (evening over night to morning) with abrupt increases due to transmissions. But never does the signal suddenly disappear.
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I think i will invest in a high pass filter to be sure i'm not hunting ghosts.
Re: Wideband spurious signal?

 

On 15/05/2025 06:52, Kevin Kettinger via groups.io wrote:
i'm investigating the upper frequency ranges of the tiny SA ZS-407 and i've found three very strong wideband signal around 8.56 GHz that i find odd and i'm not quite sure they are really there.
I don't see those on my ZS-407, Kevin. Must be a real signal, as Erik suggests.

David
--
SatSignal Software - Quality software for you
Web:
Email: davidtaylor@...
BlueSky: @gm8arv.bsky.social, Twitter: @gm8arv
Re: Wideband spurious signal?

 

This very much looks like a mirror of a mobile phone base station signal.
As you have read before unlocking the ultra mode, these wide band signals are very difficult or even impossible to eliminate using spur removal.
--
Designer of the tinySA
For more info go to

Wideband spurious signal?

 

Hello,
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i'm investigating the upper frequency ranges of the tiny SA ZS-407 and i've found three very strong wideband signal around 8.56 GHz that i find odd and i'm not quite sure they are really there.
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When spur removal is on or auto, the signal is attenuated as seen here:
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If i disable the spur removal, the signal is much stronger:
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There is some static signal in the waterfall seen (left to the center), that i think is now a spurious signal.
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Reducing the RBW keeps the signal, but still shows the spur signal:
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Any insights on whether this is an artifact or a real external signal would be appreciated.
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Thanks in advance.
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Kevin
Re: True frequency band upper limit detection level of TinySA Ultra ZS-407 and corresponding signal dropoff

 

Try to avoid using the internal attenuator by using external attenuation as the internal attenuator is not so linear for higher frequencies, hence the "reduced linearity" warning
Keep signal at mixer below -10 dBm at all time
--
Designer of the tinySA
For more info go to

Re: True frequency band upper limit detection level of TinySA Ultra ZS-407 and corresponding signal dropoff

 

Hi Erik,
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Thanks for all that helpful information. I'll make sure to keep my TinySA properly charged for future scans.?
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I¡¯m working on calibrating my TinySA Ultra ZS-407 at 7.37 GHz. The interface recommends a signal in the -50 to -10 dBm range, but I wanted to double-check:
Is -10 dBm a hard upper input limit, or is it simply the recommended calibration range? I may be using a signal source that outputs around +2.3 dBm (ADF5355 frequency synthesizer) and can add attenuation if needed, but I¡¯d prefer to know what the true safe threshold is.
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Thanks!

Adam
Re: True frequency band upper limit detection level of TinySA Ultra ZS-407 and corresponding signal dropoff

 

On Wed, May 14, 2025 at 04:26 AM, Adam Coate wrote:

Do you know approximately what actual signal strength (in dBm) causes the device to enter Overload mode, especially when scanning above 7.3 GHz in Ultra or Harmonic mode? I¡¯ve seen the warning appear even when the reported signal is in negative dBm, such as ¨C4.3 dBm for 23.8434 GHz (see screenshot below). So I'm wondering if it's possible to use the Overload warning as another method to gauge the true dBm signal strength being measured.

Sorry, can't use the overload warning to improve accuracy

Also ¡ª would using an external attenuator help delay or prevent the Overload warning in these situations? I¡¯m curious if attenuation could help narrow down the true signal strength by observing how much reduction is needed before the overload disappears.

External attenuator can help reduce overload and increase accuracy when it avoids using the internal attenuator at frequencies above 10 GHz but the true problem with accuracy is the spread over devices.
You can create your own level offset correction table for these high frequencies, see PDF document referred to in Wiki
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You should charge the tinySA.
Operating with Yellow battery indicator signals worse performance
--
Designer of the tinySA
For more info go to

Re: True frequency band upper limit detection level of TinySA Ultra ZS-407 and corresponding signal dropoff

 

Hi Erik and all,

Thanks for the detailed correction values ¡ª that's very helpful. I have a quick follow-up question about the ¡°Overload¡± warning on the ZS-407.

Do you know approximately what actual signal strength (in dBm) causes the device to enter Overload mode, especially when scanning above 7.3 GHz in Ultra or Harmonic mode? I¡¯ve seen the warning appear even when the reported signal is in negative dBm, such as ¨C4.3 dBm for 23.8434 GHz (see screenshot below). So I'm wondering if it's possible to use the Overload warning as another method to gauge the true dBm signal strength being measured.

Also ¡ª would using an external attenuator help delay or prevent the Overload warning in these situations? I¡¯m curious if attenuation could help narrow down the true signal strength by observing how much reduction is needed before the overload disappears.

Appreciate any insights!

¡ª Adam

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Re: True frequency band upper limit detection level of TinySA Ultra ZS-407 and corresponding signal dropoff

 

Quick check of a random ZS-407
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Remember the variation in sensitivity above 7 GHz between models can be huge
The ZS-407 tested has less than average sensitivity around 10 GHz
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Tested with -10 dBm input and all settings factory default:
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7 GHz? ? ? ? ? ?-0.5 dB
8 GHz? ? ? ? ? ?-6.7 dB
9 GHz? ? ? ? ? ?-14.8 dB
10 GHz? ? ? ? ?-14.9 dB
11 GHz? ? ? ? ?-16.9 dB
12 GHz? ? ? ? ?-8.8 dB
13 GHz? ? ? ? ?-5.8 dB
14 GHz? ? ? ? ? -15.3 dB
15 GHz? ? ? ? ?-22.8 dB
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--
Designer of the tinySA
For more info go to

Re: Banggood, is tinysa.org updated?

 

Max frequency i can set is 17.992Ghz
True frequency band upper limit detection level of TinySA Ultra ZS-407 and corresponding signal dropoff

 

Hello all,
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I was wondering if anyone could offer some insights about the true upper limits of the frequency bands that the TinySA Ultra ZS-407 can detect. And what the corresponding signal drop-offs are at each 1 GHz interval above 7.3ghz? I watched a video which showed the below signal drop-offs on the ZS-406 when detecting a signal generator emitting a 1 dbm signal. Since the ZS-406 is only rated up to 5.4 GHz, does that mean the ZS-407 takes another 2 GHz to start seeing similar drop offs since it's rated up to 7.3 GHz? I.E. 9 GHz would be -5.5dbm, 10 GHz would be -17dbm, 11 GHz would be -27.5dbm??
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I'm trying to make sense of some alarming signals I've been detecting from a nearby cell phone tower. I detected a 10.092ghz 4.6dbm peak signal on my back patio which is 0.78 miles / 1.28 km from the cell phone tower. Based on the signal drop off of the TinySA Ultra ZS-407, I'm guessing that may be underreporting the signal by about 17 dbm? So the real signal is more like 21.6dbm??
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Under the tower itself I've detected steady signals of 19.3 to 22.3 dbm at 10.7777ghz. So those may actually be closer to 40 or 50dbm? Any help is appreciated, thanks.?
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Adam
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https://youtu.be/ypqJMcVC-z8?si=8k55XFsBYeXlYm8V
Interpreting Those Drop-Offs (ZS-406):
Signal Generator Output Actual Frequency Detected by TinySA
+1 dBm 7 GHz -5.5 dBm
+1 dBm 8 GHz -17 dBm
+1 dBm 9 GHz -27.5 dBm
+1 dBm 10 GHz -38.5 dBm
+1 dBm 11 GHz -57.5 dBm

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Re: Banggood, is tinysa.org updated?

 

To my knowledge there are today (May 12, 2025) no clones of the Ultra+ models.
--
Designer of the tinySA
For more info go to

Re: Banggood, is tinysa.org updated?

 

¿ªÔÆÌåÓý

Hi, I think I'll chime in with my Banggood experience. I did not know about this group when I bought it, or the concerns about copies and clones were so bad.?

It also did not come with a stylus.

I don't have any complaints about it, it works good.

I did ask the seller beforehand, if it was authentic, and capable of being upgraded, because I saw their policy said "flashing firmware voids your warranty."? I did do /some/ research first.

It is the ZS-406 model, and it can measure up to 12.072 GHz after unlocking Ultra mode. Barely into the range I really want to measure (Starlink). I guess they were liquidating their older inventory, thus the sale price.

Now I wonder if ZS-407 can go higher, since the base frequency range is up to 7.3 instead of 5.4, I wonder how that corresponds to the Ultra range expansion, and how that compares to authentic hardware. Which is newer? Can the cloners make more capable hardware than the authentic version?

Thanks, Stewart


On 5/12/25 07:13, momir via groups.io wrote:

This is how looks tinysa ultra + from banggood. I dont have any calibrated signal generator to test how to measures. Seller says its genuine, i dont think so, there was no pen stylus inside.

Re: Hunting Spurious Emission at 154 MHz

 

Very interesting. Please let me know which settings have you used, as I have a similar problem in 6m band. It's a wide-band QRM. It's impulsive and is also present as well.
Re: Banggood, is tinysa.org updated?

 

This is how looks tinysa ultra + from banggood. I dont have any calibrated signal generator to test how to measures. Seller says its genuine, i dont think so, there was no pen stylus inside.

Re: Banggood, is tinysa.org updated?

 

Re: Banggood, is tinysa.org updated?

 

Re: Banggood, is tinysa.org updated?

 

Re: Auto Save Issues

 

On Mon, May 5, 2025 at 08:28 AM, Kevin Kettinger wrote:
i go to buy an Raspberry, for test you're tool, i'm beginner in those domains, i think "tsactl" have a great potentiel !
i come back to tell you.
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Thank you and all the team for you're help
Re: Level Cal -> signal level incorrect (only sometimes)

 

Hi Erik, understood, many thanks for your fast answer and have a nice Sunday.
Seb.
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