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????? I have attached my version of the schematic diagram . To get to the PCB stage I have to have the correct connections with the controller. Is anyone kind enough to tell me which pins connect LO and RX to HW-267 (STM32F103C8T6 STM32 Development Boards (Blue Pill)?
I want to clarify the following about my schematic :
RLC values are generic.
System ground does not reflect the appropriate situation in the future PCB. It's just the electrical connections. For example, on the SAW ?Epcos ?B3555 filter the ground connections for the housing are top and the signal ground connections must be to the bottom PCB plane?to avoid the "ground-loop"?.
Level Shifter is optional.
I have no connection to the attenuator because I don't know what data pins are connected at STM board.
Any suggestions on removing / adding components or changing the controller are welcome.
Daniel? Ungureanu
YO8SAK
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May I suggest you change the footprint for the impedance matching around AND between the SAW filters to CLC Pi configuration? Impedance matching between the two SAW filters can give significant improvement. There you need a footprint for CLCLC -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
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Daniel.
From what I read of Erik's Build Instructions, here's what connects to the Arduino (Nano or otherwise - not sure about the 'Blue Pill' version):
Pin? ? Note
6? ? ? ?SDO Connect to D3 of the Arduino (WARNING: You MUST use a 3.3V compatible Arduino)
7? ? ? ?SDI Connect to D2 of the Arduino (WARNING: You MUST use a 3.3V compatible Arduino)
8? ? ? ?SCLK Connect to D1 of the Arduino (WARNING: You MUST use a 3.3V compatible Arduino)
9? ? ? ?nSEL Connect the RX module to D0 and the LO module to D5 of the Arduino (WARNING: You MUST use a 3.3V compatible Arduino)
Hope this supplemental information helps.
73 de Marty, KN0CK
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If you use an Arduino with actual serial interface you may have to choose other pins -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
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Erik,
I have the 'Blue Pill' and the Nano (I bought both) but plan on using the Nano for my first build. Is the Nano what you're using, or what Arduino did you use for your build and was there any level-shifting??
73 de Marty, KN0CK
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Avoid the pins on the nano that double as uart pins -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
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I am using a 5v Nano clone.? With level shifter (4 channel, about $1
USD) for the Si4432
It seems to be working fine.? I am using a parallel PE4302 board.
Here is my pin assignments and notes, I basically arranged them for
easy construction:
// PINS SI4432, you can change these to any pin you want
const int SI_nSEL[4] = {6,7,0,0};? //gaw changed???? 2? LEVEL
SHIFTERs
const int SI_SCLK = 10 ;??? // gaw changed from 1 ;? LEVEL SHIFTER
const int SI_SDI = 11 ;??? // gaw changed from 2 ;??? LEVEL SHIFTER
const int SI_SDO = 12;??? // gaw changed from 3 ;????? DIRECT
CONNECTION, No level shifter
#define PE4302_pinbase A0??? //ALL USE Red LEDS to drop voltage for
the 3.3V PE4302
#define DB_16?? A5? //V6
#define DB_8??? A4? //V5
#define DB_4??? A3? //V4
#define DB_2??? A2? //V3
#define DB_1??? A1? //V2
#define DB_0_5? A0? //V1
73.
Gary
WB6OGD
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Avoid the pins on the nano that double as uart pins
--
HBTE Files section:?/g/HBTE/files
Erik, PD0EK
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Here's the datasheet for a SAW filter that Erik was using: ? ?? On page 6, it shows that to make it work well in a 50 ohm environment, both ports should have a series 33nH inductor attached to the part, and then a 5.6pF cap to ground on the far side of each inductor. You can't just connect two SAW filters together, you get much better results? if you have the above matching network on both sides of both SAW filters. ? ?? /g/HBTE/topic/69385413#675So between the two SAW filters, you should have a 33nH inductor in series with one port, then a 5.6pF cap to ground to drive a 50 ohm line between the two SAW filters, then a 5.6pF cap to ground and another 33nH inductor into the other SAW filter port. In Erik's notation, that would be an LCCL network, but if the 50 ohm line is short we can? just combine the two C's into one big parallel C of 2*5.6=11.2pF:? ?LCL As the calculations in post 674 note, we could get by with just a series 48.4nH inductor between the two SAW filters, no caps.? So in Erik's notation:? ?L But you have to buy the 33nH inductors and 5.6pF caps for the ends anyway, so may as well get 10 of each and use them in the middle too. So if each port has a series L and C to ground:? ? ?CL--SAW--LC-CL---SAW---LC Erik's notation of CLC (ends) and CLCLC (in the middle) seems to be suggesting the addition of caps to ground at each saw filter port, I doubt that is necessary. The above values for L's and C's are for a B3550 SAW filter. You need to consult the datasheet for the filter you wind up using to determine the correct L and C values that will match it to 50 ohms. Jerry, KE7ER? ?
On Fri, Feb 14, 2020 at 10:29 AM, <erik@...> wrote:
May I suggest you change the footprint for the impedance matching around AND between the SAW filters to CLC Pi configuration?
Impedance matching between the two SAW filters can give significant improvement. There you need a footprint for CLCLC
--
HBTE Files section:?/g/HBTE/files
Erik, PD0EK
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Gary,
MANY thanks for the info - I may change the code to make it easier for my Nano setup. For my Nano (I have three from Amazon on hand) I'm going to modify the regulator to from +5VDC to +3.3VDC and just see how it goes without changing the clock frequency from 16 MHz to 8 MHz - they say that will work. I'll let everyone know if it's acceptable for this design or not.?
Are you using the I2C pins (MISO, MOSI and CLK) for the ILI9341 display? Please advise on that.
This project is incredible - I stumbled onto this a week ago and here I thought the Arduino Nano and OLED display 'old school' VFO display project I was working on was cool...WOW. I should probably put an order together for level shifters if my regulator exchange trick goes sour...Guess I'll see that over the weekend...Please do stay tuned...
73 de Marty, KN0CK
?
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For the display you have to use the SPI pins -- HBTE Files section:? /g/HBTE/filesErik, PD0EK
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I do have a Nano running at 3.3v and 16mhz, seems to work fine.
I'm getting by with a kludgy 3.3v regulator for now,
but buying some AMS1117-3.3v regulators in the SOT-223 package:
That should make it a fairly clean conversion.
Here's the Nano CH340 clone schematic:
? ??
Procedure:
? Replace the LM1117-5.0 regulator with a LM1117-3.3 (or AMS1117-3.3) regulator in the SOT-223 package.
? Cut the trace to cathode pin of the SD101CWS diode free of the 5v rail (anode pin still goes to the USB connector)
? Add a wire from the now free cathode pin of the diode to the VIN header pin (trace goes to input to the LM1117-3.3)
? Add a wire from the 5V header pin to the 3V3 header pin.
Here is why we connect the 5V and 3.3V header pins:
The CH340 USB chip is normally powered from a Vcc of 5v,
it has a regulator inside to power the 3.3v core logic inside the CH340,
and perhaps some very light external loads of 30ma or less.
The CH340 chip can also be powered from a Vcc of as little as 3.3v and still work,
but then CH340's Vcc and V33 pins must be tied together to avoid the internal regulator's dropout voltage.
The CH340's Vcc and V33 pins are connected by traces to the 5V and 3V3 header pins of the Nano.
If you want a bunch of 3.3v regulators, here's a source for the AMS1117-3.3:
? ? ?? ??
To remove one, I'd cut the three pins free, then put a soldering iron on the heatsink tab and
lift the part out with tweezers.? Then clean away the cut pins.
But be careful, these $2 clones use boards for which the copper pads are not well glued to the board,
the pads can easily lift up off the board when hot.
Jerry, KE7ER
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On Fri, Feb 14, 2020 at 11:59 AM, martywittrock@... wrote:
For my Nano (I have three from Amazon on hand) I'm going to modify the regulator to from +5VDC to +3.3VDC and just see how it goes without changing the clock frequency from 16 MHz to 8 MHz - they say that will work.
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Jerry,
Thanks for the information - greatly appreciated. Actually, when I bought the 3-pack of Nanos from Amazon, I bought the 50-strip of regulators you cited at the same time since I saw a post in another forum outside of Groups.io that describes the Nano 3.3V mod you have, too. So that's my initial work on the Nano. From there I'll do like Erik did and put everything together on my breadboard and make it play - then either see what the layouts look like that have been spun by members of this group or PWB my own design...Not sure on that yet. I'll take a look at the mounting if the regulator on my board (I think it was through-hole instead of SMD) and likely remove it as you mentioned. I had given thought to removing it with my hot air attachment on my solder station for SMD work, but I don't want other parts becoming desoldered and cooling weird either. Either way I'll watch the pads.
Are you using Gary's code mods for ease of build or sticking with Erik's original code? Let me know that when you have a chance - I'm not against reassignments if it makes for a cleaner build, but often I do stay with the original design to keep down the errors of the build - - then get dangerous with the code design after it gets working.
Again, thanks for the information - confirming what I thought helps... :)
73 de Marty, KN0CK?
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Marty,
I tried my own 3v mod to a Nano clone(see photo).? I dropped the 5v
USB using 2 series 1n9148 diodes and the on board
shotkey diode.? Then routed the 5V USB voltage to the 5V Arduino pin
(had to cut a trace that went to the 5V
regulator).? Then an external 3.3v AMS1117 reg for the SA parts.?
Easy and cheap.? Mostly worked.? Had a problem
with the SA trace background noise stepped down from a higher
level.???? Gave up and went back to 5V with level shifters.? I left
the Nano at 16MHz, I think that may be a problem?? Maybe I got a
marginal Nano?
Changing the regulator didn't look easy.
I don't have an external display yet, just want PC display at
present.? I think SI4432s are SPI..? Erik's
code allows SPI on any pins(is bit bang).? You just need another
nSel pin(any pin)? for the display (with level shift).
You could use voltage divider resistors or red LEDs (and pulldown R)
instead of level shifters.
YES, this is a great project, have been following and working on for
a few months.? My proto is working and better
than expectations considering no shielding, no low pass filter,
marginal 433MHz filter, long wires, laptop USB
power only, etc.
I was going to get around to Farhan's Specan with estimated $100
cost (vs. $35 tinySA) and much more work with
probably worse performance and much larger unit.
I try to keep Nanos, level shifters, etc. in stock, they are so
cheap I use them like I would use transistors.
Please keep us informed.
73,
Gary
WB6OGD
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Gary,
MANY thanks for the info - I may change the code to make it easier
for my Nano setup. For my Nano (I have three from Amazon on hand)
I'm going to modify the regulator to from +5VDC to +3.3VDC and
just see how it goes without changing the clock frequency from 16
MHz to 8 MHz - they say that will work. I'll let everyone know if
it's acceptable for this design or not.?
Are you using the I2C pins (MISO, MOSI and CLK) for the ILI9341
display? Please advise on that.
This project is incredible - I stumbled onto this a week ago and
here I thought the Arduino Nano and OLED display 'old school' VFO
display project I was working on was cool...WOW. I should probably
put an order together for level shifters if my regulator exchange
trick goes sour...Guess I'll see that over the weekend...Please do
stay tuned...
73 de Marty, KN0CK
?
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Marty, It's my own code, a significant hack of Erik's tinySA.ino. Same code base compiles on both the RPi and on the Nano. Much cruft removed, though no display or encoder or buttons and such. Can be found here:? ? /g/HBTE/files/KE7ERI haven't tried it out with hardware. If I did, I know I'd be spending days playing with it instead of some other stuff here I need to get my head into. But hope to do so in coming weeks. Gary: >? Had a problem with the SA trace background noise stepped down from a higher level.??? I'd go with a 3.3v regulator for the Nano, not depend diode drops. Only thing I can think of is the difference in supply voltage between the Nano and the Si4432's is causing the Si4432 input pins to have lots of current through the ESD protection diodes. Jerry, KE7ER
On Fri, Feb 14, 2020 at 01:34 PM, martywittrock@... wrote:
Jerry,
Thanks for the information - greatly appreciated. Actually, when I bought the 3-pack of Nanos from Amazon, I bought the 50-strip of regulators you cited at the same time since I saw a post in another forum outside of Groups.io that describes the Nano 3.3V mod you have, too. So that's my initial work on the Nano. From there I'll do like Erik did and put everything together on my breadboard and make it play - then either see what the layouts look like that have been spun by members of this group or PWB my own design...Not sure on that yet. I'll take a look at the mounting if the regulator on my board (I think it was through-hole instead of SMD) and likely remove it as you mentioned. I had given thought to removing it with my hot air attachment on my solder station for SMD work, but I don't want other parts becoming desoldered and cooling weird either. Either way I'll watch the pads.
Are you using Gary's code mods for ease of build or sticking with Erik's original code? Let me know that when you have a chance - I'm not against reassignments if it makes for a cleaner build, but often I do stay with the original design to keep down the errors of the build - - then get dangerous with the code design after it gets working.
Again, thanks for the information - confirming what I thought helps... :)
73 de Marty, KN0CK?
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Gary,
Will do - I've scrounged through all my parts and have everything to build this now and will most likely program, modify, and check out the Nano today to get that going. About the only thing I don't have is the selectable attenuator at the front, but I want to get this running first before I spent any more on it. I will report back on my Nano 3.3V conversion and performance. They say it's possible to reduce the clock speed from 16 MHz to 8 MHz but I probably won't do that out of the chute. I was AMAZED at how small the filters are...I'm no newbie to building 0402 stuff under a magnifying glass (please do a Google search on KN0CK HF Upconverter - that project used 0402 parts in the later assemblies) but these filters are incredibly fine pitch - so I'm planning to use Kynar 30AWG wire to connect things up and then plant the MUCH LARGER 0802 chip caps and inductors to the pair of filters on a copper PCB much like everyone has. Of anything, building the filter is the most challenging part of this.
More as I have it...Please do stay tuned...
73 de Marty, KN0CK
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Jerry,
I am intrigued by the Pi-code you have ported and likely give that a spin after I get the Nano version running. I have a spare Pi 3 Model A that I could easily load the code onto, configure with wiringpi for the I/O and try it - so that's out there in the near future. I have a complete set of parts for that spin at-hand. It would be cool to have the I2C from the Pi control the ILI9341 display like Erik does and maybe you already have that configured in the code - let me know about that.
The fun starts later today over here in Eastern Iowa...I'm diving in with both feet and geeking until it's built...I may even pull a semi-all-nighter just to get it built so I can play with it on Sunday with a proper load of coffee to keep my eyes open... :)
Please do stay tuned...73 de Marty, KN0CK
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1st post,??? the specified filter appears to be obsolete and hard to get in VK at least.
I found this part at RS-components.com? "RF3446E"??? BW appears to be just whats needed. Approx 1MHz.? Impedance easily catered for with L match. About US$2
Edit, Mouser have them also.
glenn
vk3pe
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On Sat, Feb 15, 2020 at 04:05 PM, Glenn wrote:
the specified filter appears to be obsolete and hard to get in VK at least.
I wound up ordering these:
?(the seller kindly added the matching network performance data in an image also with an image of the module he tested also of the single filter design)
?(decided to go with the dual since can jumper with a 0 ohm resistor to study effect of using one SAW filter and maybe other matching network or filter design)
?(will have way more than I'll ever use, so for postage and maybe one dollar I can send anyone who needs some)
?(mdflyelectronics sold out after I ordered, so was cancelled regarding the 52 values 1300 pieces kit, so found this one since I don't have any inductors and have resistor and capacitor 0603 kits)
also sells single SAW Filter PCB's and cases as well as other parts too.?
Any thoughts, questions, comments and/or suggestions regarding this model filter?
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You want suggestions? Here's one: ? ?? /g/QRPLabs/topic/69666632#42281Many of these parts are quite small, I'd be hard pressed to get by without good optics. Otherwise, tough to know if you have shorts or cold solder joints or solder whiskers messing it up. Though it is possible with young eyes and maybe a bit of myopia. Another thing you need is a good temperature controlled soldering iron with a very fine tip.? Preferably two, so you can easily remove C's and R's. The solder I use on 0603 parts is 0.40 mm in diameter, the 63/37 tin+lead stuff. Lead-free solder melts at a significantly higher temperature and so is harder to work with. Unless you are stamping out thousands of boards, there's not much lead involved here.? ? But don't hold the solder with your mouth when needing a third hand like I do. Anyways, 10 for $7 is a very good price! Datasheet looks reasonable. Be sure to follow the datasheet for matching your?particular SAW filter to 50 ohms, not Erik's instructions on how to use his SAW filter. Jerry, KE7ER
On Sat, Feb 15, 2020 at 04:45 PM, jafinch78 . wrote:
Any thoughts, questions, comments and/or suggestions regarding this model filter?
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Gary,
Did you ever look further into why you had excessive background noise when running the Nano at 3.3v?
The Nano is digital, it either works or it don't.
If it don't, it will generally run off the rails in spectacular fashion.
I suspect this will come down to how you did the power supplies,
and that this is somehow allowing the SPI lines to disrupt the Si4432's.
Or perhaps the SPI wires are occasionally having trouble reading or writing
Si4432 registers.? You did remove the level shifters when doing this test, right?
Should be a 3.3v regulator on the Nano, not just diode drops.
Would be interesting to watch those supply rails with a scope when operating.
I am building up a generic tinySA.
Hope to try it with a Nano-3.3v and an RPi.
Maybe a Blue Pill and a Teensy for good measure.
The W7ZOI Spectrum Analyzer from 20+ years ago is well thought out.
He has 6dB attenuators at the LO and output ports of the diode ring mixer to
establish a 50 ohm environment.? The attenuators absorb any unwanted mixer products,
prevent them from reflecting back into the mixer and generating yet more unwanted products.
He also has an MMIC after that mixer output's 6dB attenuator to establish the front end noise figure.
A curious placement, up front of the mixer would avoid the 6dB mixer losses,
after the SAW filter would allow the MMIC to not see all the out-of-band signals.
Farhan tried other placements of that MMIC for his very similar SpecAn,
found the W7ZOI placement was optimal.
So I'm leaving space around my ADE-1 miser for a couple 6dB attenuators and an MMIC amp.
Signal levels into a diode ring mixer should be roughly 10dB down from the LO power level
if you want a linear response.? The LO is driving hard, must have diodes on either one side
or the other of the mixer fully conducting to give a path for our low level signal.
But not so hard that you burn out the diodes.
The signal should be much smaller than the LO to ensure that the signal is not determining
when the mixer diodes conduct.? For this reason, I suspect we may get best results
in signal generator mode with a -1dBb signal level out of the rx Si4432, the lowest level it can give.
Definitely not 20dBm!.??
Will be interesting to play with.? Unfortunately, I have no way to determine how clean
a 250mhz sine wave is.
Jerry, KE7ER?
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On Fri, Feb 14, 2020 at 03:50 PM, wb6ogd wrote:
I tried my own 3v mod to a Nano clone(see photo).? I dropped the 5v USB using 2 series 1n9148 diodes and the on board
shotkey diode.? Then routed the 5V USB voltage to the 5V Arduino pin (had to cut a trace that went to the 5V
regulator).? Then an external 3.3v AMS1117 reg for the SA parts.? Easy and cheap.? Mostly worked.? Had a problem
with the SA trace background noise stepped down from a higher level.???? Gave up and went back to 5V with level shifters.? I left the Nano at 16MHz, I think that may be a problem?? Maybe I got a marginal Nano?
Changing the regulator didn't look easy.
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Marty Wittrock
jafinch78 .