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Re: tinySA Tracking Generator article

 

On Thu, Jan 16, 2025 at 09:42 PM, VK3DPM Dave wrote:
To adjust diplexers,?duplexers filters?etc better off using a VNA.
Ideally, yes.? But finding a VNA that costs less than $500 that has the dynamic range and sweep speed to do so real-time does not appear to be currently available.? My main point was that there are still some scalar measurements where having a tracking generator might allow you to make S21 measurements that the current crop of NanoVNA and LiteVNA's cannot perform as well.
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Again, I have not read the full article, so I don't know what dynamic range the author's build is capable of achieving.
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Herb
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Re: tinySA Tracking Generator article

 

To adjust diplexers,?duplexers filters?etc better off using a VNA. A spectrum analyzer / tracking generator only provides amplitude, a VNA measures S parameters i.e. amplitude?and?phase etc. Always terminate all unconnected ports of a DUT.? ?


On Fri, 17 Jan 2025 at 11:31, hwalker via <herbwalker2476=[email protected]> wrote:
On Thu, Jan 16, 2025 at 11:43 AM, MaxPi wrote:
I can hardly imagine the need to get another ten dB of dynamic range beyond the 80 dB available from the litevna.
? I just checked my litevna and above 3.5Gz you don't get anywhere near 80 dB of dynamic range.? I haven't read the full article but for tuning duplexers a tracking generator could be a handy accessory.
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Herb
Re: tinySA Tracking Generator article

 

On Thu, Jan 16, 2025 at 11:43 AM, MaxPi wrote:
I can hardly imagine the need to get another ten dB of dynamic range beyond the 80 dB available from the litevna.
? I just checked my litevna and above 3.5Gz you don't get anywhere near 80 dB of dynamic range.? I haven't read the full article but for tuning duplexers a tracking generator could be a handy accessory.
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Herb
Re: Presets and Frequency Markers

 

Thank you, pa3cqn. That's a perfect explanation. It really helps me.
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Re: tinySA Tracking Generator article

 

I can hardly imagine the need to get another ten dB of dynamic range beyond the 80 dB available from the litevna. But if I needed it, I would simply add a mixer to this pair of devices.
Re: tinySA Tracking Generator article

 

On Thu, Jan 16, 2025 at 10:09 AM, MaxPi wrote:
What's the point if for the price of this generator you can buy a Nano/Tiny VNA that will give you much more data than just a frequency response?
On the first page of the article the author points out that the tinySA with a tracking generator has more dynamic range in dB for measurements of filters than S21 mode of a typical NanoVNA.
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Roger
Re: tinySA Tracking Generator article

 

What's the point if for the price of this generator you can buy a Nano/Tiny VNA that will give you much more data than just a frequency response?
Re: tinySA Tracking Generator article

 

Here is a readable version of the first page as a zip file
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First page.zip
First page.zip

tinySA Tracking Generator article

 

There has been some interest in the past about building a tracking generator for the tinySA.? Here is an excerpt from an article in the current issue of QEX magazine from thje ARRL.
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Re: Waterfall pattern disappears from the TinySA Ultra display screenshot #ultra

 

Ah, nevermind, there's a workaround right here!

/g/tinysa/topic/waterfall_not_included_in/105884949
Re: Waterfall pattern disappears from the TinySA Ultra display screenshot #ultra

 

Anyone found a workaround to this? The first thing I saved to the SD card was a waterfall plot capture, so the issue as described by the OP jumped out at me.

I wonder if you could put the capture on a timer? So initiate a SD card capture, give it a name and a delay time, and then let the screen fill back up with some waterfall content before writing to disk?
Re: What to do when a selftest fails

 

I've got an order pending for U22 from Digikey but if there is something else that might be borked on my unit I'll wait for more comments here, thanks.
Re: What to do when a selftest fails

 

The external gain is zero, but thank you.
TinySA Ultra+ ZS-407 Unboxing and Calibration

 

Here's a video about?
TinySA Ultra+ ZS-407 Unboxing and Calibration

Re: Presets and Frequency Markers

 

That is a totally different jog action than I would expect.?
Re: Presets and Frequency Markers

 

Jog Step used then you select change start/stop/center/span frequency at bottom (click on this values at bottom, on select you see > on it)
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And use leveler for step
Re: What to do when a selftest fails

 

In some versions of the firmware, the external gain setting is persistent (as it should be), but it's not reset before a self-test. This was corrected in later versions.
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Try resetting the external gain to 0 and rerun the self-test...
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I was caught by this several times myself...
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M
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Re: What to do when a selftest fails

 

5W with 40db of attenuation is still -3dBm, far, far, too much to do any sensible measurements, even if you do not damage the unit!!
You need at least another 20dB of attenuation to get things into the range where good measurements can be made.

73
Jeff G8HUL


________________________________________
From: [email protected] <[email protected]> on behalf of PT via groups.io <paultwa00@...>
Sent: 13 January 2025 06:54
To: [email protected]
Subject: Re: [tinysa] What to do when a selftest fails

More info since I looked at my notes - ref post 19061 above

Unit came with 177 firmware installed. I put 185 then 189 on it.

Unit worked for a month or so no issues, no errors, calibrated fine.

Now I find the self test errors as above

Used a 40db attenuator on it and attached a 5W output radio to it.

Perhaps I took out U22 ? With the 40W attenuation and 5W it 'should' have been fine, no?
Re: Presets and Frequency Markers

 

When you set a marker it is a display-only marker. When you load from presets the closest datapoint is set as the marker.
These don't have to be the same.
You can test this by using the jog-wheel and step up-down to see if you get the same marker frequency you entered.
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The auto calculated stepsize for the jog wheel is (Fstop-Fstart)/(datapoints-1).?
You could change either Fstart or Fstop to align your marker with a datapoint.
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Let's say Fstart is 700 and Fstop is 800. The jog-step is 100/449 = 0.22 .
Round this up to a value 733 can be aligned with gives 0.25.
Fstart could be Fstop-449*0.25 = 687.75.
Or round down to 0.2:?Fstart will be Fstop-449*0.2 = 710.2
In the same manner you could add the calculated result to Fstart and change Fstop.
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Notes:
- wether this behaviour is intended is up to Erik. I can understand someone to expect the stored marker to stay the same.
- The jog-step is also related to the number of sweep points, and re-calculated when you change them, as is the marker.
- I noticed that changing the jog stepsize in config>more>jog step doesn't seem to work. E.g. if I set it to 10 MHz to step quickly through the scan it doesn't.
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Re: What to do when a selftest fails

 

More info since I looked at my notes - ref post 19061 above
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Unit came with 177 firmware installed.? I put 185 then 189 on it.
?
Unit worked for a month or so no issues, no errors, calibrated fine.
?
Now I find the self test errors as above
?
Used a 40db attenuator on it and attached a 5W output radio to it.
?
Perhaps I took out U22 ?? With the 40W attenuation and 5W it 'should' have been fine, no?
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