Putting the "Ek" in "Geek"
The Workbench
Elecraft K1 Internal Battery Pack (KBT1) Upgrade
Aug 24th
I really like my Elecraft K1 QRP rig. Mine’s the 4-band model (40, 30, 20, and 15 meters). I also have the KAT1 internal ATU and the K1BKLTKIT backlit display installed. It’s a great rig for QRP CW in the shack or in the pack. Mine is a staple of my Field Day excursions.
Typically, when I hit the trail with my K1, I pack a 2-AH gel cell to power it. Works great, but the gel cell is kinda heavy and bulky. So, in a moment of boredom (I had the itch to build something, I guess), I ordered the KBT1 internal battery option and installed it.
4Nec2 Input File for Shortened Antenna Model
Feb 9th
Here is the 4Nec2 input file for my shortened antenna model:
I welcome any comments on the validity of the model.
Note that I make no claims that this is a super antenna. It works. It appears to suit my needs, given the constraints under which I designed it. I’ve documented my antenna design and building efforts here in my blog mainly so anyone who might be interested in learning about and using antenna modeling software like 4Nec2 might find the information useful. In my case, the model appears to predict behavior that’s consistent with the actual performance of the antenna. This is good–and cool.
Some Antenna Pictures, and Three More Bands!
Feb 8th
It’s high time I posted a few pics of my new antenna. First, the loading coil. This was made from a stock MFJ inductor (3″ dia, 10 turns/inch). the center rod is a nylon rod I purchased from U.S. Plastic, and the brass fittings are 1/8″ NPT couplers and a nipple from McMaster-Carr.
20m Shortened Vertical On the Air–On 40m!
Feb 3rd
I was able to steal some time this weekend to construct the 20m shortened vertical I’d been designing using 4Nec2. It didn’t turn out quite like I was planning, but it’s good nevertheless. I used half-inch-dia aluminum tubing and a section of an MFJ prewound coil to build it, and I used construction techniques stolen largely from AD5X’s portable vertical design. The main differences between his design and my implementation are
- I used a single 6-ft aluminum tubing section on the bottom instead of constructing multiple smaller sections.
- I used another single 6-ft aluminum tubing section above the coil instead of the telescoping antenna.
- My coil used only 3″ or so of the MFJ prewound coil, and I used a length of nylon rod instead of wooden dowel. Mine is also tappable with an alligator clip.
- My antenna has a 30″ brass rod forming a tee at the top of the radiating element, as a capacity hat.
Antenna Modeling with 4Nec2 and Wine, Part Deux
Jan 30th
Last week I told you about how I’d gotten a nice free antenna modeling package for Windows called 4Nec2 to run in Linux using Wine. Since then, I’ve been able to create a few models and run them, and I gotta say I’m really impressed with the capabilities of 4Nec2. I doubt I’ve even scratched the surface of what’s possible, but it’s worked flawlessly for me so far. I have experienced a few minor glitches that are the result of running under Wine, but those are minor and easily worked around. Mostly, those glitches are associated with trying to run the help file, and I haven’t spent any time trying to fix those things. No big deal, as far as I’m concerned, and certainly not a knock on 4Nec2 itself.
Antenna Modeling, Courtesy of Ubuntu and Wine
Jan 23rd
I’ve already written a couple of times about my efforts to use antenna modeling software to design a new antenna for the back yard. My original plan for a four-band vertical is perhaps overly-ambitious, so I may scale back to designing some sort of short vertical for 20m that’s both sturdy enough and inconspicuous enough to leave erected in the back yard for more than a few hours at a time. In the mean time, I continue to use Phil Salas’ ultimate portable vertical when I get the chance. But I digress.
Since I launched this little project, I managed to sidetrack myself by converting completely over from Windows XP to Ubuntu Linux. If you know me (or perhaps you can detect this from my blog entries), you know that I tend to be thinking about several different ideas at the same time, and this often results in my making little or no progress on any of them because I can’t focus on any single idea for very long. Maybe it’s an attention span deficit or something. And such appears to be the case with my antenna project. But while I continue to enjoy learning about the wonders of Linux (and I confess I’m thoroughly enjoying Ubuntu so far), I figured it was time to get back to antenna designing.
Antenna Modeling…
Dec 11th
Anyone who’s been reading this blog (and I can probably count that number on one hand) knows that I’ve been thinking about a new (to me) antenna design. Being in a covenant-restricted neighborhood, I can’t erect a permanent obvious-looking antenna. But the neighborhood covenants are not extremely restrictive, I have nice neighbors, and there doesn’t appear to be any actual HOA that actively searches for covenant violations, so I figure I can get away with an antenna with a reasonably small visual footprint that I only put up when I want to play radio. To top things off, I have no trees or other readily available antenna supports, so whatever I end up using must be free-standing. The obvious choice, at least to me, is a vertical antenna.
