Month: October 2021

Building a 3D printed portable vertical antenna

I have a problem.

It is probably a common one amongst hams but it takes significant amount of time, effort, and resources in my spare time.

……

I like to create/build/home brew things. Like…all the time.

Its a sickness (or so my wife thinks).

Anyway.

I have had a QRP Guys Portable Tri-band Vertical kit for a while, and it is a great kit that is easy to assemble and works great. It is small, lightweight, and provides 20/30/40 meter coverage. Run the radiating element up a collapsible pole and you’ve got a field antenna that sets up quickly.

Since I was raised an “Army Brat” and it was drilled into me from an early age that “two is one, one is none”, I never stop at having just one POTA/SOTA vertical antenna system.

My Super Antenna, CHA MPAS Lite, Buddistick, Wolf River Coils Silver Bullet, and others can attest to that.

I might have another problem – antenna addition!

After having spent some time researching options, I decided on the following factors being important to me:

  • No kit – I’ve done multiple kits and while I enjoy them and will still do more in the future, I wanted to build something more “DIY” than that
  • Lightweight
  • Multi-band (Ideally 20/30/40/60/80)
  • Most parts (if not all) are already in my possession amongst my surplus of wires, connectors, and such
  • Inexpensive in case I do have to buy anything (i.e. less than $10 USD) out of pocket (not including what I have already purchased for past projects)
  • Occupy some degree of free time 😉

I then settled on wanting a tapped coil design that would allow me to play with the tuning to find the sweet spots per band, and after looking at various home brewed ideas, I found SA2CLC‘s Vertical Antenna Loading Coil on Thingiverse.

Printing the Parts

It checked all of the boxes above and, after downloading the STL files, I begun printing the coil form and mounts. I have a couple of printers, but find that my Flashforge Adventurer 3 provides the most consistent ABS prints for me. I’m not a fan of the constrained print area of this printer, but it does do a good job at whatever I throw at it.

The photo above is about 90% complete. I have to give SA2CLC a lot of credit for an elegant design. No supports are needed to print this model, and it is well laid out and logical. Great work!

I chose to use ABS and printed the parts at 50% infill at standard quality. My goal here was to have a balance between weight and strength, with ABS widely used in products where durability matters.

About 15 hours later I had three parts; the coil form itself, and two mounts which allow you to affix the coil to a telescopic pole.

Upon completion of the print, I immediately realized a mistake on my part – I chose ABS for all of the parts, and the two mounts require some flex in the prongs so that they can be inserted into the body of the coil.

ABS doesn’t like to flex like some other plastics do, and I quickly snapped one prong off of the first piece I tried to insert into the coil, so I kicked off another print of just the mounts using PETG. That is what SA2CLC used and posted to his model page on Thingiverse.

That is another problem I have – reading the directions!

I then sent off a print to my Creality Ender 3 (I don’t have the higher temp nozzle to allow for PETG prints on the Flashforge – yet) and within a couple of hours had two new mounts that won’t break on me.

Assembling the Coil

In addition to the ABS/PETG printed parts, I used the following materials:

  • 1.25″ non-insulated alligator clips
  • SO239 chassis mount connectors
  • 18 gauge aluminum wire
  • 6-32 machine screws and nuts
  • 4mm binding post connectors
  • short length of 18 gauge wire to connect the center plug of the SO239 to the coil
  • ring terminals
  • aluminum tape (see below)

I followed the excellent YouTube video that the creator posted as a part of his model. The two places that I deviated slightly was first in connecting the ground for the SO239 to the binding post connectors. Why? I had seen this used in other projects online and had been wanting to apply it to a project of mine for a while, so I went ahead and added it here. Time will tell if this is effective or not, or even if it will stay put or not.

UPDATE: I found some thin sheet metal from some ducting work I had done previously that I decided would be more durable than the aluminum tape shown in the next photo. I cut out a piece that is roughly the same dimensions as what is shown below. As before, we’ll see how effective this is over time.

You can see the white PETG mounts on the bottom of the coil – one left and one right.

The second deviation was the use of another 6-32 machine screw and wingnut for the radiating element connection instead of a binding post as in the creator’s design. As with the aluminum tape, I may change that out but I’ve used wingnuts on multiple antennas and find them to be solid connections that are still quick to add/remove wires to. That is especially true when the wires use spade connections.

We’ll see how it goes in the field.

Stay tuned for Part 2 – Assembly and Initial Testing

CWOps Basic Course – Final Review

I’ve been done with the CWOps Basic Course now for a couple of weeks and felt that it was time to post my thoughts on being a participant of the program and what I got out of it.

They offer multiple courses for different skill levels.

  • Beginner (Introduction to CW and learning the characters)
  • Basic (Build head copy skills and on-air QSOs)
  • Intermediate (Recognize words as sounds, increase head copy speed)
  • Advanced (Move rocks with your mind while wearing a Jedi master as a backpack)

Ok, I made that last description up, but you can see the progression from start to finish and Advanced is really about getting that speed up which includes contesting speeds of greater than 30wpm.

Already having spent quite a bit of time learning the characters, I started with the Basics course. This is very much a student driven course. That means that they have developed the program which lasts 8 weeks, and have setup practice routines for every day in-between. It is up to the student to drive their own practice and effort. Students then meet twice weekly as a group with a CWOps Advisor.

Classes are virtual and make use of both audio and video to ensure that everyone is able to interact as necessary. We practice using Farnsworth at 20+wpm and begin at 6wpm spacing, ramping up to 12-14 by the end.

Personally, having a group of like-minded individuals that were coming together at relatively similar skill levels to converse and grow together made a huge difference in my advancement in CW. This honestly surprised me as I tend to be more introverted by nature.

Our advisor was Christopher Barber – WX5CW – and I couldn’t have asked for a better mentor. He is driven for his student’s success, passionate about CW and getting on-air, and a generally great guy. Always available to answer questions, as we progressed in the class he even took time out of his weekends to try and get on the air for practice between sessions.

All that while balancing work and family.

At the start of the program in late-August, I had done a couple of “QSOs” (I use quotes since they were embarrassingly bad on my part and sometimes incomplete).

Having just completed the course, I’ve racked up 30+ QSOs all across the US and have even done one POTA activation. I am operating at 13-14wpm, whereas I was previously stumbling through a QSO at 6-8wpm (if that).

Instead of abject terror when I send a CW, I am incredibly more comfortable copying what I hear and even asking for clarity when I cannot do so (instead of fearing a whole new onslaught of dits and dahs that I won’t understand).

They say that the “proof is in the pudding”:

How do you like that pudding? Each grid square is a CW QSO that I’ve done since the start of the class. None of my classmates are included above – all are random on-air QSOs with strangers.

Verdict

In the end, I cannot recommend CWOps courses highly enough. You will get out of it what you put in, but I believe that for any skill level they have a well thought out course and anyone looking to become more proficient in CW would benefit in some way.

Classes run three times each year, and you can sign up at their registration page.

I’m signing up for the Intermediate course if that tells you anything.

Lab599 Discovery TX-500 Firmware Update – 2021-10-14

Looks like the fine folks at Lab599 dropped another firmware update for their popular transceiver, the TX-500.

From the changelog:

v1.11.02 (2021.10.14)
- Added voice beacon mode
- Extended 60m band range
- Minor bug fixes and improvements

You can pickup the files here.

First Time POTA Activation (for real this time)

After last weekend’s failure to activate Afton State Park (K-2466), I decided to take my learnings and head back out to the park.

This time I chose to record the session so that I could go back and review. As a new CW operator, this is invaluable and I’ve done it at home with just an audio recorder to check my progress and blind spots – I highly recommend doing so.

I chose 20 meters and had 10 contacts within about 30 minutes of being setup.

Anyway, here is the video:

For reference, here is what I took with me:

  • Elecraft KX3
  • Chameleon Antenna MPAS Lite w/coax and necessary BNC adapter
  • Elecraft KXPD3 Paddle
  • Bioenno 4.5Ah Lithium Iron Phosphate Battery (overkill for what the KX3 draws)
  • Sony ICD-UX570 Audio Recorder
  • Pencil and Paper for recording QSOs
  • iPhone 12 for POTA spotting, RBN, etc.
  • Goruck GR1 for hauling everything
  • Elecraft AX1 as a backup antenna

Here is what RBN saw on 20m:

And here is a map of the QSOs I logged on 20m:

A great day in a beautiful part of my home state in all the glory of fall colors.

First Time POTA – sort of….

I just completed the CWOps Basic Course and decided to take my new and improved CW skills (or lack thereof) to the field

Afton State Park (K-2466) is the closest state park in my part of the Twin Cities suburbs, so I packed up my KX3 and Wolf River Coils vertical and headed out the door this morning.

A beautiful early fall day awaited me along the St. Croix river which forms the border between Minnesota and Wisconsin.

After arriving, I quickly setup my Wolf River Coils antenna which had already been tuned from earlier use for 40m. This was mistake number 1 – knowing that 40m is not particularly great for mornings, I chose convenience over propagation.

Live and learn.

I setup the radio on a park bench close to the pavilion and restrooms area in the above picture. Being fall, I had to first cleanup the walnut husks the local squirrels dissected and left everywhere. Without thinking I sat down on the bench and didn’t think about the walnut oils which make excellent stains.

Mistake number 2.

I only called CQ for a couple of minutes before I had my first contact – KA0WKG gave me a 579 in Colorado. I started to think that maybe 40m wouldn’t be too bad today and I might get this activation done in no time.

Mistake number 3.

It was another 30 minutes of calling CQ before I landed another QSO. I did have one station come in between the first and second, but after giving a signal report they mysteriously vanished with no report back to me, so I’m not counting that one.

K9IS in next-door Wisconsin came in with a 559.

Another 20 minutes before my third and final completed QSO for the morning happened, with K0NIA in Iowa (also next door) providing a crisp 599.

With time running out for me today, I packed up and headed down the road towards home. Activated or not, it was a great day to get out of the house among the trees while still enjoying a great hobby.

Wolf River Coils 80-10m Vertical

So lessons learned:

  • Be ready and willing to change bands in order to match the conditions. This is obvious and something that I recognized at the start, but chose convenience instead – especially after getting the first QSO in short order.
  • A longer wire antenna or even a taller vertical might have increased my ability to both get out and be heard. RBN wasn’t showing great propagation for me – even at full output on the KX3.
  • Watch where you sit 😦

Get out and get on the air!