Topband: Takeoff Angle

[KN4LF, T. F. Giella]

Bud W0HG Said:
I think the take off angle is everything..During one of the contests this
season I was absolutely unable to work a couple of LOUD (30 over)Texas
stations using a vertical.

Thomas KN4LF Says:
   I would not expect to see close in one way propagation on 160 as
mentioned above but takeoff angle is very important for close in ragchewing
versus DXing. Here in Florida a group meets every night on 1847 kc +/- year
round. Most of us are within 50-100 miles of each other here on the central
peninsula and all of us either have separate verticals/Tee's and low dipoles
or use the KK4TR switching arrangement where actuation of a relay makes the
single antenna a Tee vertical or dipole/doublet.
  We are rarely able to communicate with our verticals within the state,
especially with the linear off. There is a skip zone on 160 just as 80 just
not as pronounced. During winter and during the low part of a sunspot cycle
the skip zone  becomes more noticeable. All of our verticals model out on
EZENEC 3.0 with a takeoff angle between 18-30 deg. and our dipoles 90 deg.
Generally we work out to around 500 miles +\- ( to KK4CA) strongest on the
dipoles and the verticals usually win at 1000 miles +/- (to N4CQC). The
verticals also win better then 95% of the time between Florida and Europe.
Occasionally though when the E Valley-F layer duct is closed our low dipoles
get better reports in Europe by 3-6 db.
  We do ragchew through out the summer QRN season here, many nights with the
QRN +20-40 over. The high radiation angle dipoles and linears make it
possible, sometimes aided by DSP noise reduction.

73,
T. F. Giella, KN4LF