Friday, February 22, 2008

PSK-20 kit completed.. finally

psk-20.jpgI ordered the PSK-20 kit, a PSK31 crystal locked transceiver for 14.070Mhz (the most active spot for PSK31) from SmallWonderLabs back in October 2007. Three months later it arrived.

It's a great radio. Plugs directly into your line in and out on a computer, I'm using a USB audio adapter as shown above and a Mac with the excellent CocoaModem software. Transmit comes on when you start sending, an inbuilt vox, which is great as my other arrangement involves an external vox box I put together to drive my Yeasu radio.

Construction wasn't completely smooth for me. One part, a surface mount 1uH inductor was missing and a bit difficult to source locally. Once complete the receiver worked right away but I had no output on transmit.

I traced RF through to U8, an MAR-3 surface mount rf amplifier that came already soldered on to the board. Mini-Kits were able to send me a couple within days. Still no rf out, it seemed like the output power transistor Q11 an MRF261 was dead. And it seems I'm not alone in this, at least back in 2001.

Found it difficult to find a substitute until VK2ZAY kindly offered me a 2SC1969. The leads are BCE instead of BEC so there's a bit of air sculpture going on but it works and I'm certain it's putting out at least 5W.

I did write to SmallWonderLabs about my problems but he hasn't replied so far.

I would certainly recommend this rig, it would go really well in a travel kit with a laptop, a wire to hang out the window and a small end fed tuner.

The box is excellent, definitely order it. All metal and the board is mounted by sliding into a rail.

Yes, I had a few challenges getting it going but the benefit is that I'm familiar with how it works and improved my skills somewhat. Perhaps all kits should have some bugs?

Update: I did get a reply from smallwonderlabs and today 14-Mar-200 the missing inductor and a replacement MAR-3 have just arrived.

2 comments:

Glenn AE0Q said...

Hello From Colorado! Glad you got the PSK-20 going, Peter. I bought one about 5 years ago but gave it to my brother for Christmas along with a Warbler (PSK-80) that I built. Now I have another PSK-20 that I got on e-bay that didn't work after the builder was finished, I have to troubleshoot the transmitter. Hope to work you on 20m when the bands open up a bit, that should be soon! 73 - Glenn AE0Q

Peter B Marks said...

Thanks Glenn, I'll listen out for you.