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Hi Erik,

Normally you would manually just decide upon which combination of signals you wished to use, based on the usual formula, but I guess you could set them up automatically (or choose which sets to use) as long as you know the frequencies of the test signals in use.

So for an IMD 2 & 3 test you would probably only need four or six markers in total (including the two test signals) but would maybe need to be able to select which sets of IMD products you wish to use for the measurement. The usual constraints are the operating frequency range of the item under test, and which set of 2nd and 3rd IMD products that are produced are the highest in level. You would normally do a quick check of the various sets and then just use the worst case values.?

Let me think about this and I'll try and give an example. I think there may be some manufacturers guidance notes (possibly Keysight) somewhere on-line too.

Regards,

Martin

Maximum is 8 markers

Steve, great offer, much appreciated?
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I think the markers are the more important features when using this mode.

Would it then be possible to add some additional measurement functions such as harmonic levels relative to carrier and also 2nd & 3rd order IMD.

Ideally with the option to specify an off-set to the level of the two test signal carrier levels, to compensate for any notch filters that may be used ahead of the analyser to prevent overload during such tests.

The ability to see small concurrent slices of narrow frequency bands, makes it possible to use small bandwidths in each slice, which is not possible with the wide sweep that would normally be required to encompass all of the carriers and their complex harmonics and IMD components.

IP2 & IP3 could then be calculated and read directly.

Regards,

Martin

I have created a GUI front-end for the script and complied it to a Windows .exe much simplifying the installation and operation of it.?

It also incorporates Jason Glass' amplitude bug correction.

Find it here:

https://github.com/bradbbot/TinySAforRFguys/tree/main/TinySA4RFDialog

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Note that the qrpkits attenuator will not run at 5 watts continuous at all settings.? If only the 20dB stage is engaged, the 2 watt input resistor of the pi section sees over 4 watts.? If you are careful of which stages are engaged and which end is driven at high power, you can get the 5 watt performance.
--John Gord

On Thu, Feb 23, 2023 at 01:15 PM, Roger Need wrote:

https://www.amazon.com/Nooelec-SMA-Attenuator-Kit-Line/dp/B07YYMT65T

I like that set as well.

larry

@Kurt, just watched your video and it is very good and very helpful.?

@Erik, I will rewrite your first use page incorporating my comments.? I'll post it here and you can decide to use none of it, all of it, or any portion of it as you wish.?
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Steve Johnson

? ? ? K0OIL

On Mon, Feb 27, 2023 at 07:02 AM, Erik Kaashoek wrote:

Updated multi band screen layout.


With bands with span less then 1/3 of the total span the info will start to overlap, not sure how to solve this without too much code.
Increasing the space below the chart to stack the info conflicts with the waterfall.
Feedback?

Erik,
? On older spectrum analyzers without markers the "freq/" annotation is a necessity.? With the Ultra's ability to place up to 8 markers, the "freq/" annotation could be removed to save space as the markers are more accurate than estimating frequency using the division scaling. Maybe an additional mode that cycles full screen through the different bands with "touch to continue" could be added as suggested by those who prefer that display format.

Herb

Oh forgot, the assembly manual?
has the schematic and resistor values...

wb7ond

I have one of these:??
41 db, 5W continuous, 10W short time...
DC-200 Mcs....
Works pretty good, decent accuracy, not HP 355 but still very usable.
I think they are $25.

Regards
wb7ond

Hi Erik, I did find the Updating Firmware wiki page but that page could also be clarified for new users in much the same ways.?

As a general guide, instruction pages are most useful (in my opinion anyway) when they:
1. Provide a condensed overview of the procedure (sort of a “This is what we are about to do”
2. Use numbered steps in the procedure with the details/considerations/options/success verifications/warnings for that specific step
3. Provide addendums, references to further info, etc.?

I guess the pages are “good enough” as is, these are just suggestions to make it a bit easier for the neophyte.
--

Steve Johnson

? ? ? K0OIL

I think displaying the bands one at a time, with a selectable delay between each scan - say 0 to one second - would be best. You'd still be able to simultaneously monitor up to 8 bands without touching anything, and no data would need to be lost. There could also be an 'infinite' delay selection where each band would remain until the screen was touched, which would advance to the next band.

With 5 bands this is just possible


I see there is still an error with the band split (blue line), it walks away.
The grid is the same for all bands with the current space allocation (based on span per band)
With less than 1/5 of the pixels per band some info has to be removed.

Just to show the effect of multi band on the dynamic range (20dB extra)? see this, similar measurement time


and with 10kHz RBW (same as multi band) you get 16 seconds scan time


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On Mon, Feb 27, 2023 at 06:02 PM, Erik Kaashoek wrote:

With bands with span less then 1/3 of the total span the info will start to overlap

In this case it is possible to replace the overlapped full band info strings with abridged ones (or may be simply?just use?band numbers (i.e. B#1, B#2, ...).?
And leave the detailed info available at the sidebar menu.

Perhaps only the start frequency and the division (/) is enough información for a band

Updated multi band screen layout.


With bands with span less then 1/3 of the total span the info will start to overlap, not sure how to solve this without too much code.
Increasing the space below the chart to stack the info conflicts with the waterfall.
Feedback?
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Did you find the wiki page on updating the FW?

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Switchable/variable attenuators and power attenuators are two different things.? Good luck finding a switchable 5 watt attenuator, at least one that you can afford.

It is good to have an assortment of attenuators.? I have a handful of the 2 watt, 6 GHz, SMA attenuators like Roger Need recommended, 2 each of 3 dB, 6 dB, 10 dB, 20 dB, and 30 dB.? I also have a few that look pretty much the same but are rated to 18 GHz or higher (and are priced accordingly).? In addition, I have 20 watt and 50 watt 20 dB attenuators rated to 3 GHz of this variety:

plus an 18 GHz, 10 watt, 10 dB attenuator, and a 0-82.5 db toggle switch attenuator which I think is rated at 1 watt and up to 1 GHz.? If you think you might need an attenuator bigger than 5 watts down the road, you might as well buy a 10 watt or 20 watt or 50 watt now.? It won't be convenient to carry around with you though.? For hunting RFI, it will definitely be more convenient to use the small 2 watt SMA attenuators, but they would almost certainly survive momentarily transmitting into them with a 5 watt HT.

You probably don't need to worry that you will get too much energy into the spectrum analyzer from powerline noise, BUT, I am the cautious sort, and I would start with an attenuator inline anyway.? A lot of people that I have worked with in the past have burned up the front end of a spectrum analyzer, I never have.? Better safe than sorry!