The official Elecraft site lists all the mods and updates for the KX3, but doesn’t collect those with serial numbers in one spot. I’ve made a list of the ones documented.Continue reading
Category Archives: Amateur Radio
$11 Base for Magnetic Keys and Paddles
Want a base for your spiffy new Morse Code paddles with a magnetic mount? Try this jeweler’s bench block. It is 13 oz. (375 g), has a shiny surface that magnets stick to, and a grippy silicone base. Plus, it is only $10.99.
The key is a UMPP-Academy made by GM0EUL. It looks like other 3D-printed keys, but it uses the same precision bearings that Begali uses. I have the extra magnets mounted on the sides of mine to increase the force needed to make contact. With the built-in magnets, it was just too touchy for my big, clumsy fingers.
It is plugged into an Ultra PicoKeyer, which is more keyer than I’ll ever need.
RF Exposure Calculations for Emergency Commmunication
I’ve calculated some safe distances for RF exposure in typical emergency communication situations. These are for a 5 W HT (handheld radio) or a 50 W mobile, on 2 m and 70 cm, each with typical antennas. The results may also be useful for other VHF/UHF portable activities, like ARRL Field Day, Summits on the Air, or Jamboree on the Air.
Very short version: The 6-7 foot social distance we’ve learned to keep is safe for a typical fixed or mobile em-comm deployment. This is the distance between any part of the antenna, including the radials, and a member of the general population. 5 W HTs are safe for handheld use.
The FCC introduced new RF exposure rules for amateur radio in 2021. Hams used to have special exemptions, now we need to do RF exposure evaluations for all uses. If your transmitter and antenna are like the setup used for these calculations, you might be able to use these results. If yours are significantly different, this should help you get started.
Is ARRL Field Day a contest?
Despite Betteridge’s Law, the answer is “yes and no”. ARRL Field Day is designed to offer different things to participants and the public. It’s a floor wax and a dessert topping!
Koss SB-45 vs Yamaha CM500
My Yamaha CM500 headset finally died last year, so I tried the cheaper Koss SB-45. I hated the Koss. Sent it back and bought a new Yamaha CM500 headset.
The Yamaha headset sits around my ears, the Koss on top of them. The Yamaha grabs my (big) head fairly lightly, but the Koss was a head clamp. The Koss headset was immediately uncomfortable, then I gave it another try and it was still uncomfortable. It smashed my ears painfully against my head.
For years, my “ham shack” has been equipment crowded on top of a crate surrounded by other crates and boxes. It was neither attractive or effective.
Can you find the radios? The VHF/UHF rig on the floor would be stacked on the dresser for the weekly Monday night ARES/RACES net.
USMC Antenna Handbook
If you’ve been looking for a practical, free introduction to antennas, the US Marine Core Antenna Handbook (MCRP 8-10B.11, 2016) is a good place to start. The book is especially good for simple HF antennas that can be put up at home or in the field.
BaoFeng HTs and Spurious Emissons
The January edition of QST has some disturbing data about dirty transmitters in BaoFeng HTs.
Amateurs are responsible for their transmitters being clean, but most of us don’t have the test equipment to check that. Also, manufacturers must meet the FCC regulations for every transmitter sold.
The ARRL Lab set up at hamfests and tested the HTs that hams had with them. Over four years, only 5% to 9% of BaoFeng HTs passed the test. Alinco, Icom, Kenwood, and Yaesu had 100% pass rates. Wouxon improved from 83% to 100% over the years.
How to get an Amateur Radio License
What are the steps for getting your first amateur radio license?
Start by taking an online test for the Technician license. It is easy and free. You will probably do better than you expect. After the test, note the areas that you need to study. hamstudy.org and hamexam.org are free sites with practice tests. You only need a C (75% correct) to pass.
Simple Base for Morse Code Key
I wanted to mount my Morse code key on a base so Scouts could use it at Jamboree on the Air (JOTA) this coming October. A $15 walnut “display base” from Amazon was just the right thing for that. Now we can set up a “Send your name in Morse code!” station.
The key is a CTE-26003A “Navy Flameproof” that I bought when I was first licensed, back in the early 1970’s. I’ve never used it and it was never mounted on a base. It looks brand new. The “CTE” manufacturer code is for “Telephonics”, which matches the name on the key.
Plastic Pipe Roof Antenna Support
I noticed a clever antenna mount on another ham’s roof, so I built one myself. Putting my VHF/UHF antenna at the highest point of the roof has really improved my ability to copy some of the far-flung participants in our weekly ARES/RACES net.
A cradle built from two-inch ABS DWV (drain, waste, and vent) pipe sits across the ridge of the roof. Legs two feet long go down on each side and a two-foot section is a vertical antenna mast.
Rig on a Board Update 1
The “rig on a board” is working well. I’m a little worried about it scratching the central console, so the next version should have a cloth surface there. I’ll probably use a thinner board with some carpet or corduroy covering it.
Rig on a Board Prototype
This is a first cut at a removable mount for my VHF/UHF rig. Until now, the radio has been sitting on the passenger seat, but that is far from ideal. So I put together something simple that holds the rig steady and puts the display and controls at a better angle.
One end of the hinged board goes between the seat and the center console. The other end holds the radio. The power cable is dressed with a velcro tie behind the radio.
Using a Mobile Antenna as a Temporary Base Antenna
For our July Fourth Safety Watch this year, I used my dual-band mobile antenna on a ground plane mount on a camera tripod. I’d purchased a Nagoya GPK-01 NMO Ground Plane Kit ($28) to test my NMO mobile antenna, because my mag mount seemed flaky.
As I was drifting off to sleep one night, I thought that the 1/4-20 screw on my camera tripod might fit the holes on the ground plane kit. It did, so now I have a robust, free-standing, dual-band antenna for em-comm use.
Voile Ski Straps
Better than bungee cords! I purchased a few of these, thinking they might work for strapping my fiberglass radio mast to posts and stuff. They are great. Stretchy, adjustable, and super easy to fasten and unfasten. After I tighten a strap, just releasing the tension almost always catches a hole on the buckle to secure it. Lovely design.
Here is one of the two I used to strap my mast to a railing on top of Mt. Umunhum for a SOTA activation. My shortest straps are red and 15 inches long.