Putting the "Ek" in "Geek"
The Workbench
Doin’ the Lindy
Feb 15th
The parasitic Lindenblad, that is. I wrote in a previous post about how I was gathering the parts to build the parasitic Lindenblad antenna for 70 cm that appeared in an article in the February 2010 QST magazine. Since then, I’ve actually managed to build one of these beasts, and for what it’s worth, it even looks like the one in the picture in the article. My first trial with it on a good pass of AO-51 was less than impressive, though. For this trial, I used my Kenwood TH-F6A connected directly to the antenna with a three-foot section of RG-8X coax (to minimize the effect of feedline losses, which can be appreciable at 70 cm). There were moments when I had good copy on the satellite, but they were few and far between. I was a little disappointed, but I wasn’t ready to give up yet. Knowing that the antenna, being more-or-less omnidirectional, didn’t have much gain (especially compared the the handheld Arrow Antenna yagi I’d been using), I wondered if a preamp might be necessary.
As if “Parasitic Lindenblad” Isn’t Funny Enough
Jan 30th
A few weeks ago I posted about a new Chinese ham radio satellite, and mentioned a couple of satellite antennas I was considering building. Just a few days later I found the latest QST magazine in my mailbox, complete with an article about (you guessed it) another ham radio satellite antenna project! This one, by AA2TX, describes an antenna he calls a parasitic Lindenblad (here’s a link to an AMSAT article). The antenna, for 70 cm, is right-hand-circularly polarized with an omnidirectional radiation pattern. This makes it well-suited to amateur satellite applications. I liked this design better than some of the others I was considering, so I decided to give it a whirl.
New Ride, New Radio?
Jan 10th
When shopping for a new car, a ham isn’t thinking about performance, color, or gas mileage. Instead, he’s asking himself, “Where can I put the ham radio?” It’s not that a ham will necessarily disqualify a car from consideration based on the ease with which a 2-meter rig can be installed. Rather, he looks at it more as an interesting engineering challenge–the more interesting, the better. After all, if it were easy, it wouldn’t be interesting, would it?
I certainly made things interesting for myself last week when I purchased a 2007 Pontiac G6 GT hardtop convertible. It’s quite a car–200-hp 3.5L V6 (not overwhelming, but adequate), power everything, heated leather seats, awesome Monsoon sound system with XM radio and a 6-CD changer–it’ll be nice and comfy for my half-hour-each-way daily commute.
SENA Bluetooth Adapters with Digital Setting Circles
May 25th
Eddie from Australia wrote me recently to tell me about his success using a serial-to-bluetooth adapter to connect his Digital Setting Circles board to his laptop (avoiding the serial cable which is an obvious tripping hazard, especially in the dark during an observing session). Eddie is using the SENA Parani-SD 200 serial-to-bluetooth adapter connected to the DSC board, and the SENA Parani UD100 USB-to-bluetooth adapter with his laptop.
A Box for the Digital Setting Circles Board
May 25th
A question from a builder of my Digital Setting Circles project caused me to notice a plastic enclosure that another builder had used to contain the circuit board for that project. Oscar’s web page gives a nice narrative on how he built my project, and this page shows a nice enclosure with a clear plastic top he used for the project. The box came from Jameco, and it appears to be part no. 141832. Make no mistake–you’ll have to cut holes in the sides for the serial connector, encoder connectors, and battery connector, but at least the box is about the right size and looks to be easy to work with. I’m sure there are other suitable enclosures out there, as well.
If you’ve used another enclosure and liked the results, leave a comment below and tell me about it.
Adapting to USB…
Dec 21st
A comment that I receive frequently about my Digital Setting Circles project concerns the fact that it uses a serial port rather than a USB port. I guess manufacturers don’t typically include serial ports on notebook computers or PDAs anymore. In my own defense, USB was just coming into common use when I designed this circuit about ten years ago, and USB is more complicated and expensive to implement.
A Weekend Mechanic Once Again
Nov 15th
I have finally seen the day when my oldest child has left the nest and gone out in the world in search of his fortune.
Okay, he’s a high school teacher, so fortune might be a bit of a stretch. Nevertheless, he’s earning his own paycheck, paying his own bills, and putting his own food on the table. One of his parting gifts from me was the title to my 1994 Ford Escort. He’d been driving it around at college for the past four years anyway, so I certainly wasn’t going to miss it, and it had been a good car.
Of course, one of the first things to eat out of his initial paychecks was–you guessed it–car repairs. His front brakes needed to be done, and he needed new tires.
El Cheapo Tilt Stand for the Elecraft K1
Aug 24th
I already told you in a previous post about how much I like my Elecraft K1. I use it mostly in the field, when we backpack up a mountain or trail for an event like Field Day or one of the QRP field events held each year. The one drawback of the K1 is that having the controls on the front panel instead of the top makes it harder to use when you (and it) are sitting on the ground in the woods. Usually, I’d just find a rock or something to stick under it to prop up the front (and I can show you the scratches on the bottom of my K1 to prove it). Now, let it be known that Elecraft offers the KTS1 Wide Range Tilt Stand as a possible solution to this problem. And I’m sure that it’s a fine product. I was a little put off by the $35 price tag, though, so I finally decided to fashion a stand of my own.
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.
