Antennas in the Suburbs

At my previous QTH in Kennett Square, PA, we had lots of space and so instead of putting up a tower I used switched vee beams to cover various directions, about 270 feet each leg, which worked great on 40 m and up. Moving to Princeton, NJ, because of work lead to a lengthy break from radio. We have a decent sized lot here but not enough for vee beams or rhombics, so after a few years here a more conventional rotary beam was the answer for the high bands. Here’s a picture of the 3-ele Steppir just after it went up in the air.

Steppir in the air 2010

At a little over 40′ high, this set-up works great towards EU, ok to ZL, but not so good towards JA. This is easily understood by looking at a HFTA analysis. First, here’s the terrain at my QTH, in four different directions: 40 deg (EU, dark blue); 245 deg (ZL, red), 300 deg (VK, green) and 345 deg (JA, light blue). Princeton is on the edge of some low hills, with a plain to the east. To the south and east the terrain is pretty favorable, but to the north and west the ground rises gently in the local area, and more so within a mile or so.

HFA analysis K3EL terrain

A HFTA analysis for 20 m is shown below. EU gets a bit of a boost at moderate elevation angles which is great for a lot of signals (very low angles are less important for this relatively short path). Because of the fairly low height of the antenna, very low angles are poor in all directions, although better towards ZL and to a lesser extent EU where the terrain in the immediate vicinity of the antenna slopes away, effectively increasing the antenna height. On the other hand, to the north and west the rising ground tends to reduce the signal at low to medium angles.

HFA analysis K3EL gain

Bottom line, ok, but one of these days we need to move to the top of a hill somewhere with no zoning restrictions. 🙂

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