Or you could buy a copy, ready-made in the factory in China:

https://www.aliexpress.com/item/RS-918-10WATT-HF-SDR-Transceiver-RX-1-8-30MHz-TX-All-HAM-HF-BANDS-SSB/32827781026.html

Thanks, CockpitBob. I just ordered one. It is a great find.

Oh how I love eBay.

DingBat

How long is the radiating part of your boat's insulated backstay? Thank you.

Youkits (a Chinese manufacturer of decent QRP radios) used to sell a 3-cell 12v lipo battery pack to fit some of their CW transceivers and also run their rather nice little antenna analyzers. Unfortunately the carriage services eventually put a stop to their selling the battery packs. I know because I tried to buy three packs myself. They reached Australia but were sent back to Shanghai and I believe Youkits was fined. So they do not sell the battery packs anymore.

Why do I tell you this? Because the cells inside were exactly as described previously. Three 3.7v 18650 cells with a small voltage-balancing circuit board soldered on and neatly shrink-wrapped. The package could be charged by any 12.5 to 13.X charger, and would not overcharge.

So now I have bought some of the 3S cell-holders from off eBay, and bought 3x Youkits (a Chinese manufacturer of decent QRP radios) used to sell a 3-cell 12v lipo battery pack to fit some of their CW transceivers and also run their rather nice little antenna analyzers. Unfortunately the carriage services eventually put a stop to their selling the battery packs. I know because I tried to buy three packs myself. They reached Australia but were sent back to Shanghai and I believe Youkits was fined. So they do not sell the battery packs anymore.

Why do I tell you this? Because the cells inside were exactly as described previously. Three 3.7v cells with a small voltage-balancing circuit board soldered on and neatly shrink-wrapped. The package could be charged by any 12.5 to 13.X charger, and would not overcharge.

So now I have bought some of the 18650 3-cell-holders from off eBay, and bought three 18650 lipo cells locally. (A rip-off from Jaycar Electronics at A$15 each.) But at least I will have another useful way of running a QRP radio in the field. I also bought a NITECORE D4 Digicharger which will run off 12v DC or AC mains (110-240V), and charges up to 4 cells at one time.