-=> Quoting N6dx@aol.com <=-
N6> I keep hearing of people putting up invertel "L"s and dipoles for
N6> topband. I must question the logic. An inverted L radiates more
N6> horizontal than vertical and therefore radiates mostly straight up.
This correct except that the H and V maxima are at right angles to each
other, i. e., the H lobe is 90 degrees to the plane of the antenna, while
the V lobe is IN the plane of the antenna. The H lobe is at least 3dB
GREATER than V and at a high vertical angle. The H has a deep NULL in the
direction of the V, while the V is down 9 or 10 dB in the direction of H.
So, if you still want to put up an inverted L, make sure you direct the
sloping wire in the direction you want to work and it will put up a nice
V bidirectional lobe at 20 degrees. Note, however, that the antenna will
actually radiate more H at a high angle off the sides.
A very simple solution to this problem is to simply connect a SECOND sloping
wire at the apex and convert the L to a T. There is again V directivity in
the plane of the sloping wires, but the H radiation will be WAAAAY down.
Running this on AO shows the H to be down at least 12 dB from V.
73 Bill
N6CQ@paonline.com
___ Blue Wave/QWK v2.20 [NR]
|