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I've got a fair bit to learn about the Si4432, but here's my take thus far:

If the Si4432 can be coaxed into giving us a dynamic range of 120dB in detecting a signal,
that's quite good.? I don't see anything yet in the datasheet describing how much of that 120dB
is in the ADC's and how much is had by adjusting the gain of the PGA, best guess is around 50-50.
So when scanning at the maximum bandwidth allowed by the SAW filter and the Si4432 is
not trying to discriminate, we might get 120dB.? Which is great!.
But when using DSP algorithms in the Si4432 to bring the resolution down to 3khz, it would be
limited by the bits in the ADC's, and thus have less dynamic range for whatever happens to be
in the 1mhz or so of spectrum that the SAW filter allows through.? Still a very useful feature.

If by using two of the B3790 SAW filters I can get over 100db of dynamic range
on a 120khz RBW, I'll be very happy.

The datasheet of the B3550 used by Eric can be found here? ??
That guy is now obsolete, Mouser is recommending the B3760 as a replacement.
The B3730 is cheaper than the B3760, and looks to me about as good.
Both of those replacements seem to have a better stopband at 437.5mhz as shown in the graphs.

> RSP1 is a I/Q mixer into a 10bit 10MHz ADC

And the RSP2 has 12 bits, the RSP1A has 14 bits.
But the tinySA can be much cheaper than any of them.
And is fully hackable, which is my primary interest.

Jerry, KE7ER

I'm afraid this will never run in Wine/Mono.

Mono is the open source version of .NET, but apparently not completely so....
The closest thing I could find about this error is this :



If the error I encounter is related to what is being said there, SA.exe cannot run in Mono.
This is a sad thing, because a lot of people are using Linux nowadays....

Maybe the alternative can be to install Virtualbox in Linux, and install windows in a VM.
Just need to figure out how a virtual com port can be mapped onto a physical one on the host.

73,
Hans

No clue.
It worked on any computer I tried
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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

A well known fairly cheap SA solution for HF applications is the RSP1 combined with PC SW.
I thought it would be interesting to compare the tinySA performance with the RSP1 as the RSP1 also uses an (internal) upconverter when doing measurements below 50MHz. The backend of the RSP1 is a I/Q mixer into a 10bit 10MHz ADC
I ensured the scan time for both SA's was comparable. First a 10MHz signal at -20dB. The results are comparable except the RSP1 has a weird -63dB signal at 5MHz. Noise floor of a tinySA is a bit lower



Then a test to see how well both SA's handle a 0dB signal. The tinySA starts to show some spurious signals but still fairly clean and the 2nd and 3rd harmonics are still more than 40dB below the fundamental. The RSP1 shows signs of overloading as the 2nd harmonics is only 25dB below the fundamental and many more intermodulation products appear



The last test is a -90dBm signal at 10MHz. With a 16k FFT and 125Hz bin size the noise floor of the RSP1 is too high so the signal is not visible where the tinySA drops its noise floor using a 1kHz resolution filter sufficiently to observe the -90dBm signal. Be aware the RSP1 becomes a real-time spectrum analyzer when you are below a 1MHz span which is a big advantage for certain measurements and the FFT based resolutions filters are much better.



Only with a 500k point FFT with a 4Hz bin size the noise floor of the RSP1 drops sufficient to have the same SNR as the tinySA


A last observation is the excellent linearity of the SI4432 signal strength measurement as the observed levels are within 1 dB of what they should be.

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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

Hmmm,

If I install dotnet in Wine, Mono gets uninstalled.
Then, when trying to run SA.exe, I don't get the error I had. Instead, I get the error that Mono is not installed.
Reinstalling Mono, and starting SA.exe just gives me the same error as above again......

What version of .NET are you using ?

I ordered a 2.8" touch display with exactly the same intend!

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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

While waiting for the last SA-parts (The SAW-filters) I have combined the software from
https://www.changpuak.ch/electronics/Arduino-Project-VISIONARY.php
with the HyperVFOSI_New from Erik.

A few photos attached.

73 de oz9ny, Niels

Hi Erik,

Goed plan !
I think I forgot to install .net as well in wine.
Going to work on that....

Tnx,
Hans

Mmmm. I'm using .net data visualization. Any chance you can find an emulator with .net data visualization?
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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

Hi,

Just tested SA.exe in Linux (Debian 10) using Wine (4.0.3) but it does not seem to be working.
I installed vcredist_x86, and when I start regedit using wine, I can see the registry key of vcredist,
so I'm assuming this dependency has been fulfilled.
The attachment shows the error message I get, but this does not help me at all.

Anyone here that got this working ?

Thanks,
Hans

For a standalone unit everything is in the files area (the .ino file)
For usage with windows or linux with windows emulator there is an executable (SA.exe) that enables control from a PC

I will be renaming the files shortly
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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

try this search? "windows emulator for linux"

On Friday 27 December 2019 11:15:36 am erik@... wrote:

I could not resist to make the tinySA with its tiny display operational.
All local control goes through one rotary encoder with push button.
Local settable are from (MHz), to (MHz), max display (dB), min display (dB) and attenuator (dB). Resolution width is automatic.
First a picture of a 150MHz wide scan to see if there is any signal. Vertical scale is from -100 till -20 dB

Next is after zooming in to 5MHz till 10MHz range

The reduction in noise level due to the reduce resolution bandwidth is clearly visible.
Performance is almost identical as when using with PC control.
Standalone operation is nice when you quickly want to check for presence of certain signals or harmonics
For serious measuring the PC application is a must

Arduino source in the files area is updated to this latest version. It has not been tested if the PC application still works.....

I've been following this discussion with much interest. And _this_ is seriously cool! :-)

I may have to have a go at building one of these...

The only obstacle that I'm seeing so far is the requirement to be able to run an exe file -- I don't run windows here, not at all. Been running nothing but linux since 1999. Is this do-able as a standalone unit? I haven't hit the files section yet, but will be ordering some arduino stuff in the next couple of days. Can you point me at what I need to download to make this unit happen?

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

Thanks!

On Sun, Dec 29, 2019 at 01:14 PM, Jerry Gaffke wrote:

Perhaps the software you have written for MSWindows assumes a wider SAW, and thus won't work?

My SW ignores the maximum rbw. Thus no problem.

90dB is considerably better than what the Si4432 can do. which I believe is more like 60dB.

Please read the datasheet. The range is120dB
?
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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

Eric,

Yes, it's easy to get carried away thinking what one might do,
never get around to doing anything,?
One of my meta-hobbies.

I am thinking I should start out with your tinySA as described, and go from there.
Should run on my ancient XP laptop.

The B3555 is obsolete, though there are other RF360 series SAW filters for 50 ohms that are of similar bandwidth.
I would prefer to use the narrower B3790 SAW filter if the only downside is scan times,
as the passband is very well behaved and the stopband is twice as deep as the wider SAW filters.
The B3790 can strip out any strong signals just 100khz away that could disturb the Si4432 detector.

Once that works, I'd like to?move it to a RaspberryPi, showing graphs using pyplot.
I don't have much interest in coding GUI's, but could kick it off from a command line for each measurement.
Hard part is figuring out the SI4432 registers, a description of the serial protocol used for the Arduino would help.

And maybe then start playing with AD8310/AD8307 detectors and alternate local oscillators.

> Only having a 120kHz resolution filter will make certain SA applications impossible.

Perhaps the software you have written for MSWindows assumes a wider SAW, and thus won't work?
If so, would you consider making the SAW filter bandwidth a configuration setting in your next release?
Are there any other issues, besides being slower when scanning wide chunks of spectrum?


> Next of being able to resolve two closely spaced signals a 3kHz resolution filter also gives substantial less noise.

I assume you are pointing out the advantages of the narrow bandwidths that the DSP algorithms embedded in the Si4432 give us.
I was thinking maybe use the AD8310 for fast wideband sweeps at a bandwidth determined by the SAW filter if speed is an issue,
the Si4432 detector (at reduced dynamic range) when?narrower bandwidths are required.
(Those wideband sweeps won't be very fast unless a LO is chosen that can be quickly updated.)

But the performance of just the Si4432 as a detector is quite good for the price, hard to beat.
A good starting point.? And perhaps good enough that it will also be my ending point.

> Further the AD8310 has only 95dB (at best) range, in reality you will lose about 5dB due to noise ingress as the AD8310 is a extremely wideband logarithmic detector

90dB is considerably better than what the Si4432 can do. which I believe is more like 60dB.
On page 21, the AD8307 datasheet shows a way to extend dynamic range to 120dB, if somebody really wants dynamic range.
Page 18 shows how to use a narrowband tuned input network in front of the AD8307 to buy a free 8dB of gain.?

Going to an AD8310/AD8307 plus just crystal filters to determine bandwidth is more expensive, more difficult to build.
But could have better dynamic range than the Si4432, and be easier to code for.
If I ever got around to actually doing it, which seems unlikely.

I have my order in for some Si4432 modules.

Jerry, KE7ER

There are measurements that require a lower noise floor than the tinySA can offer. A simple solution is adding a SPF5189Z based ultra low noise amplifier module. These run from 5 volt, will provide easily 20dB amplification below 150MHz and are available on eBay starting from 6$. Or you buy a bias-tee module for 1$ and a separate SPF5189Z and modify the bias-tee module to include the SPF5189Z. Be aware the bias-tee module should be intended for low frequency applications otherwise the used inductor will be of too low value for below 100MHz and finding a reputable supplier for SPF5189Z IC's on eBay may be difficult.

Bringing everything together gives a rather sensitive portable spectrum analyzer allowing you to hunt for QRM in and around the house.
The SPF5189Z is connected before the attenuator to have minimum noise



Using a small pickup coil quickly provides you with an indication of ill-behaving switch mode power supplies such as this USB battery pack which will also run the tinySA easily for more than 3 hours.
The rotary encoder used for all user control hides behind the ancient knob at the right bottom of the attached image

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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

I am running at the maximum baud rate, but I guess there are a few issues with processing of serial data on the Nano. It also has problems, to recognize optiional numbers after a command.? E.g. "W50" will be recognized as just a "W" command with a separate 5 command. Will add a few "delay(1);", which seem to fix this problem and report tomorrow on the results.?
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Joerg, ex-DB2OO

Timeout for the reply is set to 200ms.
Even a Nano should be able to reply in that time.
Are you running on maximum baud rate?
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HBTE Files section:?/g/HBTE/files
Erik, PD0EK

Thanks for the quick feedback. With a terminal program all responses where OK, this is why I asked for the critical sequence SA.EXE is looking for. I rechecked with SA.EXE and it sometimes connects to the HyperVFO. Might be,? that an Arduino Nano,? which I am using,? is a bit slow in serial communication. An ARM or ESP8266 based board might be the better choice. When I find the time, I will try with a STM32F103C8 board or an ESP8266, which will both also eliminate the need for 5V -> 3.3V voltage dividers.?
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Joerg, ex-DB2OO