Spur at 4.275 GHz on ZS-407
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Hello Erik and everyone.
I've recently purchased a TinySA Ultra+ from a local vendor and the unit has an issue. It is a ZS-407 with HW version V0.5.4 and S/N SU-407-25011571.
It has a spur at ~4.275 GHz that is present regardless of the Spur Removal or Sample Rep settings:? ?
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When I narrow the frequency bandwidth to 100kHz and turn off Spur Removal, I see that the "spur" is actually five pulses:? ?
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The instrument passes the self test and calibration successfully.
This issue was present in the factory firmware (I believe it was V1.4-195) and is still present after upgrading to the latest V1.4-197.
The vendor has checked a few other units they have in stock and they show the same spur: ?
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The vendor assures me that the units are genuine and that they get them directly from ZeenKo.
I also have an older TinySA Ultra (up to 5.3 GHz, ZS-405 maybe, it has no model number on it) and it has no such anomalies. So my questions are: - Is this device really genuine? - Is this a known issue? - Is it faulty hardware? - How can this be fixed (if it's possible)? ?
Thank you!
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Best wishes,
Andrew
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PS: This is the device in question:
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Do the spurs increase in level when you attach the telescopic antenna? No, it remains the same. And it is present even when the RF input is short-circuited with the VNA calibration "S" cap.
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Not exactly at those frequencies (or that is just a measurement error), but some of them are there with Spur Removal turned off. When I set it to On or Auto, they are gone, except for the one at 4.276 GHz.?
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Erik, I too have the 4.766GHz spur as described by Andrew. as purchased from R&L a couple months ago. The attached plot #1? is with a terminated input, Spur Removal? ON. No change with the external antenna. I don't see any other spurs. Plot #2 is the same with the Spur Removal OFF.
----------------------------------------- From: "Erik Kaashoek"To: [email protected] Cc: Sent: Tuesday March 25 2025 6:54:59AM Subject: Re: [tinysa] Spur at 4.275 GHz on ZS-407 Can you check if you see similar spurs at 1069 MHz, 2138 MHz
and 4276 MHz?
I assumed these where solved but if you still see them I have
to do some more work.
--
Designer of the tinySA
For more info go to |
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I have a similar prob?although not quite as bad, the rear of my 407 is the same as Andrew's except the serial # as expected. Mine also appears to be a little later as the serial # is greater. I've duplicated?the first 4 images for comparison. Dave On Wed, 26 Mar 2025 at 02:36, Erik Kaashoek via <erik=[email protected]> wrote:
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