12.15.23

Antenna update: it’s a quadrant antenna, apparently

12m is popping around 14:30 PT / 22:30 UTC. Those familiar with the G90 will note that the antenna tuner is turned off.

Previously, I wrote about my cursed antenna. Okay, it’s not cursed, it just looks that way. It turns out it’s resonant not on 10m, like I wanted it to be, but on 12m. I’m not sure if that resonance is because of the way that it’s set up or that I cut the legs a little long. I still have a lot to learn about antennas. Apparently, this type of antenna is called a quadrant antenna, and its propagation pattern ideally looks like this:

Mine is set up like such that the legs are north and east:

The red are the legs (not to scale) and green
is a rough outline of the propagation pattern.

This sort of makes sense, comparing the bearing and distance1 to some of my contacts on FT8 today — all of which were between 15 and 20W of power out of the G90:

  • BL02: 2341.996 miles, bearing 253.5°
  • PM57kl: 5429.074 miles, bearing 308.5°
  • FN41bn: 2750.295 miles, bearing 67.6°
  • EN10nw: 1458.967 miles, bearing 72.7°
  • FK49pk: 3428.521 miles, bearing 96.3°
  • EN71lh: 2075.933 miles, bearing 70.7°
  • EN55hp: 1854.284 miles, bearing 61.6°
  • PM53cn: 5630.352 miles, bearing 305.8°
  • EL83td: 2654.033 miles, bearing 100.3°
  • AH46cc: 4757.746 miles, bearing 230.9°
  • EL99hx: 2484.816 miles, bearing 89.6°
  • EL09sm: 1566.271 miles, bearing 103.7°
  • EN06ph: 1419.404 miles, bearing 57.1°
  • EM73oi: 2210.555 miles, bearing 85.8°
  • BL02hb: 2383.869 miles, bearing 253.1°

The contacts in italics took some work to reach, even on 20W of power. The Korean call (PM57) makes sense as one of the furthest grids I reached. The others I strongly suspect were due to propagation patterns on the antenna. In particular, I had trouble with some of the Texas and other Southern states.

FT8 has been pretty useful for exploring the propagation of both the antenna and the bands based on the time of day and weather conditions, though it’s still not my favourite mode.

  1. I don’t get the full six digit grid to my contact via FT8, so if I can’t get their grid via QRZ I use XXNNmn as their grid via NØUK’s Maidenhead Grid Distance & Bearing Calculator. ↩︎

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