What about this transceiver for club project?

VK3ZYZ

VK3ZYZ

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github.com

GitHub - threeme3/usdx: Simple and experimental (class-E driven) SSB transceiver.

Simple and experimental (class-E driven) SSB transceiver. - GitHub - threeme3/usdx: Simple and experimental (class-E driven) SSB transceiver.
github.com github.com
1685259178707.png

It looks to be a very simple design utilizing the ATMEGA328P as a SDR.
The ATMEGA328P could take the form of an Arduino Pro Mini to save having to source all the parts.
I would have to buy some FST3253 MUX switches as that is something I do not have.
This could be fun I think. Any ideas?
 
G

Geoff

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Add a portable style case, a tuner and telescopic antenna, a 12 volt battery and charger. Handheld HF portable!
Is the ATMEGA328P software suited to the Arduino Pro Mini? Or does that have to be re-written?\
Geoff VK3ZNA
 
VK3ZYZ

VK3ZYZ

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I have it complied ok as long as I comment out the DIAG stuff, otherwise it is 103% of memory. See the code attached. There are a lot of code options and versions so it would be a great project to work on and modify as you go along. I would use an I2C LCD or OLED display and free up the serial pins for example.

I've not built one as yet as there are parts I still need.
Ebay prices...
BS170 $0.25 each
LM4562 (DIP) $1.50 each
FST2353 (SMT) $2.50 each.
2x16 LCD $10.00 each ( can get better price in bulk)
Si5351 boards $5.00 each (I have some)
Arduino Pro Minis $10.00 (I have some)
Encoder with knob $3.00 (I have some)

Maybe a small audio amp to drive a better speaker. (Jaycar KG9032, $10)

Misc bits..... Electret Mic, Speaker, Caps, Resistors, Inductors, case......
 

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VK3YNV

VK3YNV

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Looks very interesting, I want to build one. Some bits and pieces are available from here

www.hamshop.cz

uSDX | Hamshop.cz.

uSDX
www.hamshop.cz www.hamshop.cz
Kits from here... https://dl2man.de/ partially populated.

Looks like oled is a build option. Filtering PCB is on the right.
403_710.png
 
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VK3ZYZ

VK3ZYZ

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I am trying to grow a version onto my Tracker board just to see if it works.
Aim is for the club meeting Sat. to have something at least partly alive.
 
VK3ZYZ

VK3ZYZ

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schematic.png

Here is a better circuit with more detail, and some mods.
I am still trying to get the code to work. It does a bit but driving the menu is sus.
Also, when the PTT is pressed, I get a pulse train of signal. Before I added the push buttons, it would transmit a carrier for a second then stop. It may be sending Morse from the keyer but I think Morse is now disabled in my latest build.
There is an order for the Op amps, MUX and FETS in the post so if anyone wants to have a go at this design, assuming it works, those parts will be available later.
 
VK3YNV

VK3YNV

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I'm not 100% clear on how it works, doesn't it need the FT3253 mux to get the phasing right, to get baseband I & Q signals into the ADC.
If so it might not do anything until you get the mux.

Also there is a typo in your parts list, I think its FT3253, not FT2353.
 
VK3ZYZ

VK3ZYZ

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There looks to be at least one PiPico version...
github.com

GitHub - lu7did/ADX-rp2040

Contribute to lu7did/ADX-rp2040 development by creating an account on GitHub.
github.com github.com
PDX_V1.0_Schematic.jpg

That may well be a better one to go with if it works.
I think it is under development,
 
VK3YNV

VK3YNV

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BillC said:
Do we need tuned circuits to make things work or are signals just chopped up these days ?
Click to expand...
Impressive tho it is, digital can only get you so far, you still need analog tuned circuits for input and output filtering.
 
B

BillC

Active member
Thanks Ray , I wondered how the received audio would sound without some filtering around critical spots in the transmitter circuit. Watching with interest, cheers! good luck Denys.
 
VK3ZYZ

VK3ZYZ

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Yes, I think it is the same, or at least, similar. There are quite a few variations.
So far, I am having a lot of trouble getting good SSB on the TX. The RX has not been built as the parts have just arrived.
It seems getting clean TX SSB is not a straight forward task as many folk are having problems. The settings are pretty critical. When time allows, I'll make up a couple of my simple sine wave generator boards to inject 2 tones into it to help with said settings.
 
VK3ZYZ

VK3ZYZ

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There is a great deal of info on https://groups.io/g/ucx/
A real lot in fact. So many posts to read that I've only skimmed a few!

For example, here is one post that has some helpful links...

This is a free tool for filter design. It is used for conventional LPFs.
http://www.ke5fx.com/aadeflt.htm
If you want a class E output stage, you can get the spreadsheet to calculate it here:
http://4sqrp.com/resource/classie/classie.html
Do note however that class E is very fussy and chances are the values you get will need to be tweaked. In addition, the BS170s are not going to be fast enough switching to get great efficiency on the 12 m band. You can use the toroids info site to get an estimate of the number of turns on a particular core:
https://toroids.info/T80-2.php
I use Qucs-s to simulate class E output stages. It works fairly well for this purpose to show you the values are close but inevitable there are going to be inefficiencies the simulation does not account for.
https://ra3xdh.github.io/
This program is also useful for simulating mixers, amplifiers, etc. as long as you can get reliable SPICE models for them.
73,
Dan
KW4TI
 
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