Post 516 gives a link to the datasheet, for a? B39431-B3555-U310
That SAW can deal with 10dbm max, so the ADE-25MH does give additional dynamic range.
?I would like to see more about the protocol between the host and the Arduino,
would make that Arduino code easier to read.?
Jerry
n? Perhaps it's been updated, but the build documentation specifies a matching network
for the SAW filter, but doesn't bother to say exactly what SAW filter was used.
toggle quoted message
Show quoted text
On Wed, Dec 25, 2019 at 09:42 AM, Jerry Gaffke wrote:
Perhaps it's been updated, but the build documentation specifies a matching network
for the SAW filter, but doesn't bother to say exactly what SAW filter was used.
|
I haven't fully figured the needs of a high end version of your tinySA
Nor have I figured out the Si5381, but you should have a look at it:
? ??
Has 12 outputs, good to 3ghz.
Mouser sells them at $16, single piece price.
? ??
The Si5382 should be cheaper, but is harder to get at this time.
They call these "jitter attenuators", but they look like full fledged clock generators
suitable for creating multiple precision clocks of arbitrary frequencies.
The SPI interface should make it possible to update them very quickly.
There's also an Si5386, which has multisynth output dividers operation off of a single DSPLL
Don't let the fractional divide put you off, looks like they have jitter issues figured out.
Another interesting part is the Si549, which is like an Si570 but good to 1500mhz.
Kind of expensive, but easy to patch into board dead bug style.
The SiLabs website and their selector guide both make it really hard to find this stuff.
? ??
I guess they assume if you are buying thousands they can have a rep drop by
occasionally and tell you about the cool new stuff you should look at.?
Jerry, KE7ER
toggle quoted message
Show quoted text
On Wed, Dec 18, 2019 at 11:24 AM, <erik@...> wrote:
Now the TinySA is fully functional I could not help thinking about next steps.
Dynamic range (IIP3, noise level), RBW filters are ok.
Going to harmonic mode above 868MHz is no fun and using below signal LO between 434 and 868 is also difficult due to the mirrors.Just in case you want to re-use as much as possible but want to extend the frequency range you have the following options
1: Increase the IF to reach 900MHz
Instead of the LO SI4432 module a ADF4350 from eBay could be used, these start at 16$. Do NOT buy a cheap black ADF4350 module as these have considerable more spurs. For best performance you will need a amplification module as the ADF4350 outputs max +5dBm and that is insufficient drive te get the best performance of the first mixer. Using a different low pass filter and a rather small bandwidth home build? 900MHz cavity IF filter you get a zero till 900MHz spectrum analyzer with the same performance.?
2: Use? a cheap extra high IF stage to reach 2GHz
As the first ADE25-MH mixer is good till a bit above 2GHz you could consider adding two ADF4350 modules, an extra mixer and a cavity filter somewhere between 2 and 2.6GHz with bandwidth of 100MHz or less. This will give you a 2GHz spectrum analyzer where you reuse basically everything from the TinySA except the LO SI4432 module. The extra cost is two ADF4350 modules for 15$ each, an additional ADE25-MH module and a home build 2GHz cavity filter (simpler to build as there are less bandwidth requirements) for about 20$
3: Ignore cost and go up to 3GHz
Another options is to use two MAX2870 modules, 2 mixers capable for 3-6GHz and a 3GHz cavity filter. This will be substantially more expensive as the MAX2970 modules go for above 50$ each
The SA.exe SW is prepared for all these options as the configuration of IF's and LO's is completely flexible. You can even go for a I/Q mixer and FFT based last IF or subharmonic mixers.
You only will need to adapt the arduino SW to control the new modules but there are complete examples for controlling a ADF4350/ADF4351 available
Let me know how you see the future of your TinySA
--
HBTE Files section:?/g/HBTE/files
Erik, PD0EK
|
Well Eric, the obvious next step is to put it all in one box so it is a true stand-alone SA. If you added a Pi with a large touch screed display to run the equivalent of your SA.exe app, youve got it. ?Maybe the Pi can do the Arduinos job too? ?Think of that... a self contained SA for under $100. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com
email:??bill@... ?
toggle quoted message
Show quoted text
On Dec 25, 2019, at 9:27 AM, erik@... wrote:
?Doing some experiments with the very cheap OLED display It is readable showing -120dB till 0dB scale and 100 frequency bins, but only with glasses <IMG_20191225_160919745.jpg> Now I need to add some buttons for full local control Would this be as useful addition? -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
A tiny display would be cool, and maybe useful once people get used to the idea
of a spectrum analyzer that doesn't have to roll around on a cart.
Me, I'd be very happy just to have something cheap that works well.
If I'm serious about making a measurement, I want to save the data to a file anyway.
Would much prefer Linux based software, an RPi would be ideal.?
An RPi-Zero is $5, can save files, displays to anything from a
cheap 3" SPI LCD to a 1080p HDMI monitor,
Can host its own software build environment.
And it can drive the SPI bus into the SI4432's, no need for an Arduino.?
Jerry
|
Eric,
Great Stuff!!!
I assume "the switch" is the small IC on the Si4432 module (a PCB assembly that we buy)
that selects either the TX or RX port from the Si4432 to be connected to the module antenna port.
And "set the first IF to zero" is done in the software, as we no longer have a front end diode ring mixer.
This was even more cryptic to me at first, just now getting my head around it all:
> If you flipped the switch before init, the LO?one would become the RX, the rx ?one will?be the LO one but it¡¯s tx goes nowhere...
By "one", I'd guess that means a Si4432 PCB module.
And the only "one" we need in single Si4432 mode is the
module that is normally used to drive the diode ring mixer LO port.
I had been assuming that the Si4432 only worked in half duplex mode,
not using the transmitter and receiver at the same time.
Very curious if you can use both simultaneously and get results good enough
on the receiver for it to be used as a spectrum analyzer.? All on one die!
Perhaps it's been updated, but the build documentation specifies a matching network
for the SAW filter, but doesn't bother to say exactly what SAW filter was used.
I'm looking at the B3790 in the RF360 series from Qualcomm.
It's cheap, Mouser has it in stock, 40db down at 500khz out and headed for 60db down.
But passband is only about 120khz wide, will this work with the current software?
? ?
Build photos appear to show two SAW filters directly connected, would it not be better
to have 2x the recommended matching inductance between the two?
Appears to me that top end of the 5dbm absolute max spec going into the B3790 SAW filter will be
the limiting factor when using the ADE-25MH.? Not clear at what power level the SAW filter
will perform well, I assume? 2 or 3 db lower.? If so, the ADE-1 could handle the same power level,
though will need an attenuator between it and the possibly 20dbm TX pin from the SI4432.
I think we're at around 10dbm max into the 250mhz filter, regardless of which mixer.
Though I suppose running an ADE-25MH with 7dbm going in may be cleaner than 7dbm into an ADE-1.
And the ADE-25MH is surprisingly cheap and easy to get.
Amazing these Si4432 modules can be sold for $2us.
Mouser's best price is $4.20us each, if you get the 2500 piece reel.
So the cheapest way to get the Si4432 chip is to heatgun them off of the modules?
Anyways, the tinySA looks revolutionary.
An excellent complement to a nanoVNA, and about as useful.
If a board were fabbed to take the 250mhz filter, mixer, SAW filters,
and sockets for the two Si4432 modules plus a Nano, it should be
very easy and cheap to duplicate.
All them SMA connectors and cables in the rig Eric built dominate the cost!
Jerry, KE7ER
|
Doing some experiments with the very cheap OLED display It is readable showing -120dB till 0dB scale and 100 frequency bins, but only with glasses  Now I need to add some buttons for full local control Would this be as useful addition? -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
Using the TinySA as a 0-250MHz signal generator
As the AD9851 modules are? becoming scarce and much more expensive it would be nice if the TinySA could be used as a signal generator.
The whole signal path from input to the RX SI4432 is bidirectional so I decided to test.
In the SA.exe I added the ability to put both SI4432 in TX mode (see setting in red circle)?  So without changing the HW configuration the TinySA input becomes the output of a signal generator able to output 0-250MHz of a fairly acceptable sinus where you can control the frequency by setting the center frequency in SA.exe and the output level (maximum -2dBm) by setting the attenuation. Always good to have a spare signal generator.
-- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
Yes. You flip the switch but you still have to set the first IF to zero otherwise the first SI4432 sweeps at an 434MHz offset When run as a receiver the IF should be set to zero because the SI4432 internally offsets to it's low IF. -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
Great! Erik, you are on top of it, thanks. If you flipped the switch before init, the LO one would become the RX, the rx ?one will be the LO one but it¡¯s tx goes nowhere... so will work, no? Your software fix is probably best. 73, Gary WB6OGD?
toggle quoted message
Show quoted text
On Dec 20, 2019, at 11:01 AM, erik@... wrote:
?I already changed SA.exe and Arduino SW to allow selecting which SI4432 is used for signal strength measurement. Only need to test You can indeed also put a HW switch on the nSel line, but both SI4432 are initialized at startup so you have to make sure both are there. For me keeping the PC based control SW generic is important. I'm now using SA.exe for 2 different SA's My updated TAPR-VNA SW can control 3 different VNA's. Really saves a lot of work -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
I already changed SA.exe and Arduino SW to allow selecting which SI4432 is used for signal strength measurement. Only need to test You can indeed also put a HW switch on the nSel line, but both SI4432 are initialized at startup so you have to make sure both are there. For me keeping the PC based control SW generic is important. I'm now using SA.exe for 2 different SA's My updated TAPR-VNA SW can control 3 different VNA's. Really saves a lot of work -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
On Fri, Dec 20, 2019 at 07:38 AM, <erik@...> wrote:
I understand, when you remove the antenna switch, you can use a separate connector for the RX part of the LO SI4432 but that would require me to make the signal strength module selectable in SA.exe. Which is not difficult, just work and I
Could we just put a switch on the nSEL line? 73, Gary WB6OGD
|
YOu need to decouple at least one of the SI4432 modules from the other components, either the LO SI4432 from the mixer of the RX SI4432 from the 434MHz filter. As at the moment you can not choose from SA.exe which SI4432 is used to measure the signal strength, its always the LO designated with '0' , e.g. the RX SI4432, its easiest to use the RX SI4432. I understand, when you remove the antenna switch, you can use a separate connector for the RX part of the LO SI4432 but that would require me to make the signal strength module selectable in SA.exe. Which is not difficult, just work and I'm rather lazy..... But it is a very good idea, one input for 0-250MHz, another input for 250MHz till 920MHz -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
Erik,
Could the LO Si4432 receiver be used ( ie: an SMA input separate from the main SA input) for this?
73,
Gary
WB6OGD
|
In the TinySA two SI4432 are used, one as a fixed frequency signal strength detector (the RX SI4432 module)? and another to sweep (the LO SI4432 module) but one single SI4432 is capable to do both so why not use that capability? There are two main reasons not to do so but for you these reasons maybe not relevant so it is good to understand them well. The first reason is the sweep range of the SI4432 build in synthesizer. Its frequency can be set from 240MHz till 920MHz and is used as LO mixer input to downmix to the internal IF of 937.5kHz. This implies the frequency range available for input is also 240MHz till 920MHz so it is impossible to measure the input signal strength below 240MHz The second reason lies in the implementation of the downconversion path inside the SI4432 The output of downconversion mixer is converted to digital and a digital mirror suppression technique is used and digital filtering to get to the required receiving bandwidth. As the performance of the mirror suppression is limited a scan using a single SI4432 of a 250MHz input signal looks like this:  The mirror, positioned just below 252MHz, is clearly visible and only 30dB below the main signal at 250MHz. Furthermore there is considerable "dirt" between the two signals. The vertical scale is not correct but I forgot what the exact values should be. Probable 15dB lower When doing a wide scan all this is much less relevant as can be seen on this 500MHz wide sweep  As this scan uses 500kHz steps the mirror is barely visible as a 30dB lower peak 4 points to the right of the 250MHz main signal. All the other signals at higher frequencies are most probably actually present and can be seen because the base SI4432 is a rather sensitive receiver at high frequencies So you can/should use a single SI4432 when you are searching for signals above the 250MHz permitted by the low pass filter and you are not interested in weak signals close to (<2MHz) the main signal. The SA.exe control program of the TinySA can easily be configured to use a single SI4432 without having to change anything in the Arduino or other SW. So you get a crude 250MHz to 960MHz extension of the TinySA for free. -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
I added a "Auto settings" button to SA.exe This button sets all settings to meaningful default values except the IF and detector configuration on the settings tab (as these should never change for a given hardware) -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
Good suggestion, I will implement as currently the SA.exe remembers all settings and comes back in its last state, but the source may have changed.... -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
Bill, I intend to compare the performance of my more traditional build 2GHz SA with the tinySA. Phase noise, resolution filter performance, noise level, IIP3 etc. If the SI4432 is doing well it could be a nice IF/resolution filter backend for the 2GHz SA as it offers more RBW filters For the 2GHZ SA I have to go to stitching FFT for all RBW below 30kHz. FFT is fast, good SNR, you can go down to a RBW of 1Hz if needed but setting up is more complex as you also need the audio input connections The tinySA is just connecting one USB plug and running one PC application and it always works. W.r.t 450MHz as limit. If you operate at 144MHz? or 432MHz, should you not be interested in the 3rd or 5th harmonic when transmitting? But then maybe most people home build HF only, no VHF or UHF For me this is all a modular tool box and everything I build should have a place in the tool box so over time I can compose whatever I need. -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
|
Erik¡ You have done a marvelous job here¡. but what is your goal?? Do you have equipment operating up in the 4Ghz+ range that needs attention¡ or is this just to do it just because? ? Most amateur radio installations never operate above 450Mhz even though there are bands available above that frequency. I suppose there is plenty of stuff up in the +Ghz range like wifi points and the like. ? For me, I will be working on making it more robust below 450Mhz¡ which should be easy.? Removing harmonic spikes and reducing the noise floor.? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Group at Groups.IO. ? email:? bill@... ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of erik@...
Sent: Wednesday, December 18, 2019 1:24 PM
To: [email protected]
Subject: [HBTE] Next steps for the TinySA #spectrum_analyzer ? Now the TinySA is fully functional I could not help thinking about next steps.
Dynamic range (IIP3, noise level), RBW filters are ok.
Going to harmonic mode above 868MHz is no fun and using below signal LO between 434 and 868 is also difficult due to the mirrors.Just in case you want to re-use as much as possible but want to extend the frequency range you have the following options
1: Increase the IF to reach 900MHz
Instead of the LO SI4432 module a ADF4350 from eBay could be used, these start at 16$. Do NOT buy a cheap black ADF4350 module as these have considerable more spurs. For best performance you will need a amplification module as the ADF4350 outputs max +5dBm and that is insufficient drive te get the best performance of the first mixer. Using a different low pass filter and a rather small bandwidth home build? 900MHz cavity IF filter you get a zero till 900MHz spectrum analyzer with the same performance.?
2: Use? a cheap extra high IF stage to reach 2GHz
As the first ADE25-MH mixer is good till a bit above 2GHz you could consider adding two ADF4350 modules, an extra mixer and a cavity filter somewhere between 2 and 2.6GHz with bandwidth of 100MHz or less. This will give you a 2GHz spectrum analyzer where you reuse basically everything from the TinySA except the LO SI4432 module. The extra cost is two ADF4350 modules for 15$ each, an additional ADE25-MH module and a home build 2GHz cavity filter (simpler to build as there are less bandwidth requirements) for about 20$
3: Ignore cost and go up to 3GHz
Another options is to use two MAX2870 modules, 2 mixers capable for 3-6GHz and a 3GHz cavity filter. This will be substantially more expensive as the MAX2970 modules go for above 50$ each
The SA.exe SW is prepared for all these options as the configuration of IF's and LO's is completely flexible. You can even go for a I/Q mixer and FFT based last IF or subharmonic mixers.
You only will need to adapt the arduino SW to control the new modules but there are complete examples for controlling a ADF4350/ADF4351 available
Let me know how you see the future of your TinySA
--
HBTE Files section:?/g/HBTE/files
Erik, PD0EK
|
Hi Erik,
Thanks for the latest improvement. You may see some new reports in the new year as some of us have parts on order from China and Poland.
One of the features Tony G3PTD and I used on our PE4302 project was to power up with a safe amount of attenuation already selected.
That way we might inadvertently avoid blowing things up. (see )
I'm excited to get started on the TinySA. Thanks for sharing this with the group.
72/3
Tony G4WIF
|
Erik,
No, I don't have experience.. actually I do not have any experience with a real spectrum analyzer, hi hi...
Have experience with? a lot of oscilloscopes with AUTO button, real handy.
Yes, sounds like what I envision except, maybe just over the range that is set...? I don't have much around
here to go up to 300MHz...? though I suppose that would be safer.
73,
Gary
WB6OGD
|
K9HZ