Sunday, May 21, 2017

YouKits SK-1A QRP 40m transceiver review

YouKits is getting a good reputation for low cost amateur radio gear. Their antenna analyser is well regarded. When I saw a new mono-band 40m SSB / CW transceiver for US$189 including postage I couldn't resist. It's called an SK-1A.

It arrived very quickly and was easy to figure out even without reading the user manual.

While it comes with a Yaesu branded speaker / microphone, it's not wired to use the speaker in it so you must use headphones or an external speaker. Note that this transceiver does not have a built-in speaker which probably isn't a bad thing given the small size of the case.

I've had two contacts so far, one local and another VK2 to VK3. Both reported good audio from me and I found reception at my end pretty good. Disconnecting the antenna shows that the receiver is sensitive enough to hear band noise which is all you need on 40m.

The display is clear and the backlight is bright. The manual includes instructions for adjusting the display but it's not brightness or contrast, it lets you switch the backlight on, off, or auto.

Internally, construction seems good with lots of surface mount components used throughout. There's no circuit diagram in the manual, which is a pity, but you can see that the 6 crystal IF is on 4.9152Mhz and there are a few SA602A balanced mixers in there along with an LM386 audio amplifier.

The VFO board behind the front panel is compact and the software works well although I find the way pushes on the knob change between going up and down in step size a little weird. The soldering on the PIC microprocessor looks a little rough on my unit but all seems to work reliably.

The final is an IRF510 and I get about 4W peak output. I like the way they use shielded coils.

Main board soldering is good but clearly done by hand rather than machine.

Internally there's a socket for the 18650 Lithium battery pack which they supply with a charger but it looks like you'd need to open the case to charge the battery.

This radio is lower sideband only (along with CW), which is perfectly fine for voice contacts but I was rather hoping to use it for digital modes which normally need USB.

While a traditional SA602 based design, this radio works well enough and is more compact than even an FT-817. 40m is a good choice for a mono band QRP radio. There's no deafening thump during receive / transmit switching like I get on some other designs and audio output is more than enough for headphones but a little low for an external speaker.


Ed said...

Thank you for your review - I have been thinking about picking one up as well.

Regarding the digital modes, is it not possible to work LSB but simply move the central frequency up?

Peter Marks said...

Edgar, that's an excellent question. I understand that some modes, like PSK, can work on either sideband because they use phase shift, but remember that that the spectrum is flipped between USB and LSB so other modes like RTTY cannot be used on LSB unless your software supports the flip. I think fldigi can do this but I haven't tried it myself.

Unknown said...

Now that you have had the radio for a year, what are your thoughts? I have order 1 and awaiting arrival.

Peter Marks said...

Kelly, I still have it but haven't used it for many months. These simple transceivers are good value but when there's a better commercial rig sitting on the bench I tend to use that rather than the worse one. I'd still recommend these for a beginner but I think, if you can solder at all, a uBitx is a better transceiver for $100 that covers all bands and I'd go for that.

HMR said...

Hello OMs,

I search the service manual / schematic for this SK-1A .

May anyone help me?

Thank you very much

73 de DH6SAU Harry.