Apartment HF Antenna “Research & Development” Adventures

Apartments and HOAs can be really difficult for hams interested in working the HF bands.

For one thing, it’s usually necessary to conceal your antennas in such small, restricted spaces. Add that indoor antennas can be inefficient, suffer from high SWR from capacitance and reflection with surrounding walls and ceilings, and you have a really hard time making contacts!

In an earlier post I detailed my work getting a little multiband Comet HFJ-350M outside my third floor apartment window using a plank, a steel L-bracket, an PL-259 barrel connector, and a passthrough panel.

I had some luck with that setup, which I ran through Field Day 2021, and was able to make a number of field day (17) contacts with it.

However my DX range was very spotty, and signal strength was often at the edge of reception. And in the morning, the sun on the side of the building seemed to be causing SWR to rise and squander my forward power to the point that I disappeared from PSK Reporter.

(I did a lot of debugging and I kind of suspect my main coax feed cable, but I never was able to prove it exactly.)

So begins Antenna Adventure Number Two

With some difficulty (that’s another story) I got my hands on a 20m hamstick to try out.

I replaced the Comet in my window mount with the MFJ hamstick, but found it was too close to the building and being taller, touched the roofline, forcing it to bend over about a foot down.

Hamstick tip kissing the roofline when mounted straight up and down

Discussions with my “Elmer” yielded the idea of angling the bracket using washers as spacers to give the antenna about a 20 to 30 degree tilt which would help it clear the roof, and get it away from the building.

So I took a trip back to the hardware aisle and grabbed some longer bolts, and washers to stack along the upper bolt, and disassembled my setup again for the 20th time.

After a little experimentation, I came up with an acceptable angle.

Repositioned L-Bracket using washers as spacers

The next hurdle was to tune the 20m hamstick. This is a chore because my indoor space is full of furniture, and the SWR readings indoors are not accurate at all compared to when it’s actually outside.

Hamsticks need to be tuned using a couple of set screws at the midpoint between the whip and base coil section, so unlike the much shorter Comet antenna, I can’t just reach out the window and adjust the whip on the fly.

I ended up needing to take it on it’s plank mount out of the window and unscrew it from the connecting cable after each reading, adjust it, and put it back again all over again to see the effects of each adjustment on the SWR reading.

This took a while to get close, but eventually I got it down to an acceptable number with the addition of a radial, again just taped to the wall with painters tape.

I probably could get this a little closer, but I was sick of hoisting it out the window!

Drawbacks of the Longer Antenna Install

I have a few concerns about this install.

The whip is rather flexible, and the wind can be pretty aggressive at this end of the apartment complex. It’s piled up our patio furniture, flipped over all our rather heavy “fake grass” outdoor rugs, knocked over plants, and some things have even just vanished entirely after a storm, carried away to the land of the lost socks never to be seen again.

So with this wind in mind, I worry about the whip snapping around and breaking, or hitting things if I don’t take it inside when the desert storms spin up.

The install is also not sealed against water at this point, so I’ll want to bring it inside when it rains (Yes it does that in Arizona sometimes!)

It’s also just a little more visible from the ground than the Comet antenna, being longer, and leaning out from the building a lot further. So it remains to be seen how long it will be till/if someone in the office notices, and whether they will take offence!

The good thing however, is that the installation didn’t create any holes to patch if we move later! I can just pull the planks out of the window and unscrew my antennas and take ’em with me! No muss, no fuss!

20m Hamstick installed outside the window
Spot the antenna! Still pretty subtle up there…

Initial Transmission Results

I finally got the antenna tuned up about 7pm and the radio, a G90 hooked up with my digital setup.

Wow! On the Air and Loud!

I snagged 8 contacts in a couple of hours between FT8 and FT4, including Mexico, Canada, and a Russian fellow living in Ecuador!

I saw DX signal reports on PSK reporter all the way into Europe, Australia, Japan, Trinidad, Italy, Norway, Finland, various islands.

Signal reports also blanketed most of the USA, and were stronger over all than those using the Comet antenna.

Given that this all happened as the band was dying late in the evening, this was a terrific result!