Steve KD1JV, designer of the ultra-portable MTR and ATS series of transceivers, has developed a portable monoband SSB/CW radio. The architecture is a tweak on a classic bidirectional superhet board with twin SA612 mixers and a crystal filter. The VFO is an Si5351a synthesizer controlled with an ATMega328 running an Arduino bootloader. It will put out ~7 W on 20m and the board is only 4" x 4" (~10cm x 10cm).
A limited run of kits was produced earlier and now Steve is considering another run, but he’s looking for about 50 people to express an interest before he pulls the trigger. If you’re interested, check out the KD1JVDesigns group at groups.io and vote in the poll (kd1jvdesigns@groups.io | Should I do another batch of Slop Bucket kits?). You can also find the manual in the files section (requires login.)
A quick update, Steve KD1JV is working on a second edition of this transceiver with an improved VOX circuit, cleaner RF output, and a much larger LCD display. It will be available for 20m or 40m and should be released near the end of January 2019.
Did any SOTA folks get hold of an SBII kit? I haven’t heard a lot about this rig.
I built an SBII a few months ago but I’ve yet to try it on air. The original firmware was a bit buggy so I installed a third party version which seems to work OK.
I didn’t have the will to make a custom case, so I bought an extruded aluminium case from Hong Kong via an online auction site for around £7 delivered.
The box was already painted black, the paint was in fairly good condition, I felt that further work was not needed.
The rig operation and features are simple. There’s 10 frequency memories, backlight and vox. There is no built in CW keyer, it’s straight key only - the mic ptt button or dedicated key with mono plug keys the rig.
Unfortunately during testing, I could not get the output power to go above 4.5watts, whatever I did. I checked all of the usual suspects and I couldn’t find any build mistakes. I’d built the rig to completion before alignment as usually my stuff just works.
I tore my hair out for long enough, so it came time to break out the emergency kit…
Thankfully the second kit is putting out nearer to the expected amount of power.
I’ve been comparing the two boards this morning and it seems as though the fault lies in the TX band pass filter, the healthy board showing a larger signal at the PA side.
My next move is to work on the band pass filter to see if I can recover the signal loss. The PA bias seems fine, it’s identical to the working board.
I’ve almost finished building the working board into the case, so at least I’ll soon have one working radio. With the other rig, I’m tempted to try to put it on a different band.
Colin,
you’ve done a brilliant job on that decorated box, not only for the bright lime, I mean!
A good move to motivate youngsters towards CW, maybe?
Hope to work you soon with your new toy.
73 de Ignacio
