SW-40 completed and on the air!

My completed rig on lower right, inside my pickup truck at the Grindstone Campground in SW Virginia

My completed rig on lower right, inside my pickup truck at the Grindstone Campground in SW Virginia

It’s a great feeling.

My thus far relatively modest journey into homebrewing had another high water point as I finally completed this QRP transceiver, and even better, made my first QSO with it out camping in the woods! The antenna was also homebrew, my multi-band jumper dipole for 10-20 m. The antenna was also used heavily with my commercial Yaesu 857D rig (barely seen on the wooden mount, upper-left). No, I’m not strictly homebrew, I do sometimes like to get on the air with all the bells and whistles of the pro-rigs. But the most joy I had, by far, was the one contact I had on 40 with the SW-40 (I wasn’t actually on the band very long, and had to use a hamstick whip antenna, or else I’m sure I would have made more QSOs).

Balun of multiband homebrew jumper dipole suspended in the trees

Balun of multiband homebrew jumper dipole suspended in the trees

The antenna was created following a much less successful attempt at camping with dipoles last year. The wires were ripping from SO-239 connectors and were very rag tag and falling apart. I knew I could do better.

The finishing touches on the rig came together nicely. I managed to find one of the old, large 1/4″ mono headset jacks from a junkbox given to me by my elmer many years back, and I used that for the key connection (my straight key uses one of these and it’s just kind of a tradition with my rigs, if space allows). You can see it at right (with a key plugged in). It put a nice touch to the creation to have something in there from fellow hams from the past.

Backside of rig

Backside of rig

I also like to put SO-239’s on my rigs. I know lots of people are using BNCs or other smaller connectors, but I like going “old school” and it mates with everything in my shack. I also like having two choices for power hookup on my rigs: the banana plugs and a power socket from Radio Shack (I believe it’s called a “type M”). I suppose I should make up my mind and stick with one choice! But I’ve found it convenient for the power hookups I typically use.

Front side with Bencher and an old "Curtis K5" keyer!

Front side with Bencher and an old “Curtis K5” keyer!

The box, in case anyone was wondering, was purchased from “QRP kits” in 2015. It was designed to be used with their version of Farhan’s BITX rigs, but I really liked it and wanted to use it for different kits too. I am not particularly skilled with metal working, nor do I have access to any specialized equipment. So having a nice box pre-made is a real treat.

The lettering is just your basic transfer lettering I’ve used since I was a teenager. It can be found at art supply stores or online. It isn’t the best way to go but I haven’t yet worked out how to do the laserjet printer transfers. I then spray some clear coat on top to keep the letters on.

This cabinet has pre-drilled holes for a speaker. I don’t currently have a speaker installed and I’d need another audio amplification stage to power one. I may add this down the road or I may not. It would drain a little more current and most of the time I prefer headphones on CW anyway.

The display was also purchased from QRP kits and itself was another kit, the KD1JV digital display. One note about this kit: it radiates some noise on 4 MHz, which is the IF used in this kit. I spent a day just tracking down the source of this “birdie” and it was driving me mad. I finally realized it was the display. Shielding helps to knock it down, but given the constraints of a pre-made PC board from the kit, it is hard to find real estate to solder a shielded box around anything. So I did a workaround of installing a power switch to the display. Once I’m tuned to a known frequency, the display goes off. It also conserves battery power which is nice when running on AAs out at a campsite.

I dug up my OLD Curtis K5 “Lil Bugger” keyer from my childhood and used it with the SW-40. It worked great! I always liked the thumbwheel to dial up what speed you want on CW, and the push button on the back to key up for tuning. I am sure more sophisticated and smaller keyers can now be installed inside the box, but this brought back fond memories of late nights on the air with an old Galaxy III and a dipole on my roof.

My one QSO was with W8IX who has the appropriate nickname “Dit”. He lives in Indiana and is a more serious homebrewer. So it seemed like it was homebrew-to-homebrew operating! Couldn’t have asked for a more fun 1st QSO with this rig, which has taken about 14 years to finally complete!


The unboxed board and display

I’m now moving on to other things. I’ve got a VLF converter board that I picked up at FAR circuits at Dayton a few years ago. I’d actually already ordered most of the parts for this, and the rest I had in my junkbox. I should wrap this up later in the coming week, if all goes well, and I hope to be hearing some interesting noises from lightning down around 5 kHz! The LF and VLF bands are pretty unexplored regions for me, so this is breaking some new ground. And I’ve never built a converter type project before (translating VLF up to 4 MHz). I guess unfortunately it’s another NE602-type project (these are truly everywhere), so I won’t be breaking new learning ground really. But it should be fun and I’ll be posting about that once it’s done.

This entry was posted in antenna construction, Camping, first light, first QSO, KD1JV digital display, SW-40. Bookmark the permalink.

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