Mastodawn

Aeaeaeargh.
Some friends have challenged me to design a working ham transceiver I can make an actual QSO with, with a damn one euro (1€) component BOM, from LCSC.
Thankfully excluding shipping, so don't have to build something like 25 or 50pcs to hit the price point. :D
But it's going to be a real challenge, as I don't actually know CW.
And I want a synthetized rig for some band VHF and up. Quite possibly 2m.
As 23cm seems to require a 1,5€ or 2€ BOM to pull off.

Yes, this post is in part to vent and in part to solicit ideas from people.

If you want to see some of my thoughts and LCSC deep dive finds, they can be seen here:
https://prkele.prk.tky.fi/~ftg/files/oneeuroLCSCchallengeRadio.txt

Andrew Zonenberg Dec 25

@ftg a 1eur bom?? That's slightly nuts lol. Good luck.

@azonenberg
Exactly! It's an insidious challenge.
It looks mayyyyyybe doable.
But requires being really thrifty with the parts and if I want it frequency agile, the PLL is going to be hacky as hell.

The person who challenged me has already shared a picture of their 2m rig's board and asked when I'm ordering pcb's for mine. :D
And I'm still like m8, I'm not even sure I can make the PLL work in the way I think I can. :|
So I some prototyping and simulation ahead.

Onno (VK6FLAB)Dec 25

@ftg @azonenberg there are dozens of single transistor transceiver designs, AFAIK, some even do voice.

@vk6flab @azonenberg
But are they frequency agile?
And yeah there are those.
One friend who's not participating, Mr. "Extremely tempting, but I want to get my phase noise measurement set done first."
Was trying to get me to do a 5.6GHz band super regen with separate transmitter VCO that's locked with a translation loop PLL.
But on 2m I have a chance of actually making a non-gimmic QSO.

Andrew Zonenberg Dec 25

@ftg @vk6flab I've never been into the minimalist / hacky side of amateur radio.

I want to be making phased array radars, or moving Gbps of data using high order QAM between X-band dishes, etc. Not going for contacts on FT8.

But have fun, certainly seems like a challenge.

@azonenberg @vk6flab
Yeah there's the pushing the actual state of the art and in general pushing the envelope.

And then there's this side of trying to see if 1eur is too cheap or not.
And can something practical be built.
Tbh I think the minimum for something that's actually enjoyable to use would be around 3-5eur BOM, as that would allow for a screen.

Matt W1CDN Dec 25

@vk6flab I'm interested in some hints on single-transistor SSB designs...

@ftg this is a rad challenge, love it!

Onno (VK6FLAB)Dec 25

@W1CDN @ftg @azonenberg

Starting point is the Pititico

https://yo6dxe.com/pititico-cw-transceiver/

Pititico CW Transceiver - 40m Band / 550mW

Pititico CW transceiver, designed by PY2OHH. One of the smallest and simplest transceivers designed around a single 2N2222 transistor.

DX EXPLORER

@vk6flab @W1CDN @azonenberg
Pititico is very cool, but sadly CW only.
And if I had to learn CW for this challenge, it would never end.

But PY2OHH has piles of neat designs.
https://www.qsl.net/py2ohh/trx.html

QRP Homebrew receivers, transceivers, transmitters

Andrew Zonenberg Dec 25

@ftg at domestic distributors I'm not even sure i could get a fixed frequency 144 MHz oscillator for $1 much less modulating it

@azonenberg
Yeah unless it was some pixie or some AM toy it would be 100% impossible with western distros. Maybe something with TME.eu. But still very hard.
Can't get 7cent MMIC's and 2cent RF transistors locally.
The current PA is going to be a 0.0200eur 2SC3357, for example.
Ancient transistor, but cheap. I hope to get 100mW from it.
Which should allow me to hit the local 2m repeater.
I have had multiple contacts on the 70cm one on the same mast with 50mW.

@azonenberg
Also, speaking of 144MHz and domestic suppliers, I think one could get a TX going and maybe mixing in the PA on RX within it.
Cheapest 24MHz xtal's with TWO in parallel, VXO'd up and then multiplied twice (x2 and then x3). Or maybe 48MHz xtal and just x3. But the 48MHz might be more finicky to VXO up to get over the lower band edge.
But unfortunately it would not be very frequency agile.

There's the whole regenerative angle, but they are hard to impossible to tame into compliance of any sort.

Adrian Studer Dec 25

@ftg there’s the MS5351M, a clone of the venerable Si5351A. Cheap, but it will still use up a substantial portion of your budget

@adistuder
Yeah, a 5351 and a microcontroller to control it would blow the whole budget.
Thus the real challenge in this, if trying to make something frequency agile.