2m antenna monopod attachment

A while back, I made a monopod to use with my camera. Handy thing to  use when I don’t feel like lugging around a tripod. Also serves as a nice walking stick.

On one of my last visits to Radio Shack, I picked up two telescoping antennas thinking that I could use them as dipole elements.

Add one section of aluminum angle stock, a bulkhead BNC jack, a couple 1/2″ 4-40 screws and nuts and now I’ve got a telescoping 2m dipole antenna attachment for the monopod.

Monopod antenna attachment
Monopod antenna attachment

It took me a while to figure out how I was going to insulate one of the telescoping elements from the angle stock. While I was studying the problem, a solution struck me: plastic wall anchor. Worked perfectly.

Tuning the antenna was a simple matter of adjusting the length of each telescoping antenna to get close to 1:1 across the 2m band.

Tuning the monopod antenna attachment
Tuning the monopod antenna attachment

Looks pretty good. I’ll check it again outside over the weekend and try it out with the HT.

Monopod antenna attachment
Monopod antenna attachment

If I hold it up in the air by the base of the pole, I can get the antenna about 2.5 m up in the air. I’m hoping I’ll be able to reach the two repeaters that are about 8 miles away a little better than I can with the HT antennas I already have.

A trio of QRPGuys kits

A while ago (back in October) I ordered a few kits from QRPGuys: a dummy load, mini-paddle, mini keyer and two digital frequency counters (PTH and SMD versions).

I finally got around to assembling the dummy load, paddle and keyer over the past week.

QRPGuys kits
Iambic paddle, mini-keyer and dummy load from QRPGuys

The dummy load was the easiest to assemble, and parts placement was pretty obvious (I’m only a little bit bothered because the resistors don’t line up…). 5 minutes of soldering and you’ve got yourself a nice compact little 12 watt dummy load that also lets you measure power output via a voltage measurement.

The mini-paddle was only a little more difficult because of the size and length of the screws being used to attach the paddles. Still a relatively easy build, although you have to be careful with the alignment of the little PCB pieces that are soldered onto the base. The hardest part was getting the little nuts that hold the paddles secured. There’s not a whole lot of space to work in, you have to hold the screw, spacers, washers and metal paddle part while trying to get the nut on, and there’s not a whole lot of screw remaining to get the nut started on. Moderately difficult to assemble.

In terms of parts count, the single lever keyer/paddle was the largest kit, but easier to assemble than the iambic mini-paddle. On the electronics side, the only thing I had to consult the assembly manual for was to find out the correct orientation for the 1N4148 diodes. Placement of all the other parts is pretty obvious from the silkscreen outlines. On the keyer side, assembly was similar to the mini-paddle, but with only one lever to worry about, getting it put together was significantly easier. I did end up leaving off two nuts for the two screws that serve as contacts for the paddle. With the nuts, the screws were just too far away from the paddle. I don’t know if the screws I got were just too short to begin with, or if the kitting changed but the instructions didn’t get updated.

True to their mission, these are fun, inexpensive little kits to put together. Looking forward to working on the frequency counters next.



Another Si5351A board

A few days ago, Jason/NT7S announced the Etherkit Si5351A breakout board was getting an upgraded TCXO oscillator with improved performance. I’ve already got a few of them waiting for me to put to work, so why not add another one.

Unlike the previous boards I bought (from the crowdfunding campaign), the latest versions now come fully assembled except for the header pins. If the thought of soldering tiny surface mount devices was keeping you from trying the breakout board, worry no more.

The 10 mW WSPR beacon app note looks pretty interesting, and I think it would be fun to try to get one set up once we’re in the new house. I’d love to see how far it could be heard.

We’ll hopefully be in the new house in a few more weeks. I’m looking forward to getting the shack and workshop set up again so I can get to playing.

K3NHI sweep system by VE7BPO

From Todd/VE7BPO/@QRPHB of QRP HomeBuilder is the K3NHI sweep system that he built. He put out a call asking for people to host a zip file of his build and I offered to stash them here for him.

Inside the zip file you’ll find a description of the sweep generator, schematics, build notes and lots of pictures by Todd.

Zip file: K3NHI sweep system or here

It’s a pretty cool looking build. I’ll have to spend some time studying it when I get a chance.

An RF probe

I camee across N5ESE‘s site and started browsing around some of his projects. He’s got quite the list of them. In his Gizmos section is an RF probe which looked pretty easy to build.

I had a set of those springyy hook-y grab-y DMM leads that were broken, so I cut off the spring-y hook-y grab-y part to use for the DMM side.

On the work bench was a perfectly sized piece of PCB from when I was experimenting with cutting and scoring PCB. From the RXTX build, I just happened to have some extra 0.01 μF SMD capacitors which were perfect for the job. A 1N34A diode and 4.7MΩ resistor finished off the parts.

I used a small hacksaw to score the PCB and divide it into three sections, cut out a notch for the diode and cut the head off a brass nail to serve as the probe. Soldering everything in place was pretty easy.

RF probe
RF probe

Soldered on the leads and a ground wire with alligator clip and put everything into a shrink wrap tube.

RF probe covered with heat shrink tubing
RF probe covered with heat shrink tubing

The full probe, with all the leads ready for some RF to measure. I still need to find a decent enclosure to shield the probe with.

Completed RF probe
Completed RF probe