Continuing on from my earlier UHF exploits, my next 70cm antenna was made from brass tubing with the same Mix 61 bead balun.
However, I eventually cut it too short as I worked on getting its resonant frequency up.
DD8SF and I thought that the issue was the feed point design, so I switched to something much simpler: brass tubing soldered onto knurled nuts that could easily be screwed onto and off studs at the feed point.
This design also was my first real foray into telescoping legs.
I also did some experimentation with traps and a fan dipole, neither of which really panned out.
The last thing I tried was a super chunky pair of aluminum tubes, targeting maximum bandwidth. DD8SF said that it was far too large for what the NanoVNA was showing, but we later determined that the issue had to do with a metallic coating on the windowpane.
Since I was stuck doing antenna stuff indoors in September of 2025, I decided to start playing around with UHF stuff, starting with this antenna, which didn't quite work:
I then tried a toroid feed, which I now know isn't suitable for 70cm because coils tend to start resonating before even hitting that band.
I still went with it anyway, though!
Since coils really aren't suitable for this band, I ended up switching to a Mix 61 bead balun instead, but the resulting impedance wasn't good, most likely because of the surroundings:
And just for fun, I threw together a basic dipole using a pair of Red Bull cans with the same bead balun, which ended up faring about the same
Even though none of those worked well enough for my taste, I didn't give up there! Tune in next time for more UHF shenanigans.
As mentioned in my previous post, I was forced to bring my antennas indoors while our balcony was resurfaced, repainted, cleaned, etc. That was no problem for the 2-meter J-pole, which I simply had to adjust.
But my 6-meter dipole needed a new feed after being mounted.
That need prompted experimentation with autotransformers and loading coils, and while it did result in a usable antenna eventually, anytime I wanted to transmit, it caused my PC's keyboard and mouse to become unresponsive!
In August of 2025, after having success with toroid coils on the magloop, I thought it'd be interesting to try such a coil on the 6-meter dipole again. While it did work, the upcoming exterior maintenance on our building prevented much more exploration on the balcony.
My next project in July of 2025 was a “magloop” antenna targeting the 40-meter and 80-meter bands. Since our balcony is very small, no other antenna options would realistically work here.
My first feed attempt was with a coupling loop, which didn't work at all, most likely because of all of the metal in the vicinity.
Next up was a toroid coil, making the whole system into a transformer.
Another feed I tried was a gamma match. (I'm not sure why I didn't immediately pursue the toroid coil route when it worked better than the coupling loop.)
Since the toroid coil from earlier worked better, I ended up going back to that route, albeit with far fewer turns, which almost worked!
My final choice of feed for this incarnation of this magloop was “The Doohickey”: a box with a switch between two different taps on the toroid coil, as the impedance match needed to be different based on the desired frequency range.
And it was paired with the addition of a second vacuum capacitor to bring the resonant frequency of the loop down. (I intended to put a switch on that could add or remove the second capacitor, but I've yet to get to this at the time of writing.)
After asking some of my radio friends on Fedi about what would be good for 2-meter on my balcony, I went with their suggestion of a J-pole antenna back in July of 2025, which was really easy to work with from the get-go!
Because it worked so well, I'm still using it to this day, albeit with an improved feed line, but that post will be up later.
In June of 2025, In order to increase antenna bandwidth considerably over the wire dipole, I switched to some copper piping that I bought from the hardware store, cut, soldered wires onto, and painted.
This one also featured a 1:1 current balun with an old cannabis jar enclosure.
Because of the low feed point impedance, I also tried a 1:4 current balun, which didn't work at all for this purpose.
After discussing with DD8SF, I tried a twin coax feed, which almost worked!
