ANTENNAS FOR 100 POUND DXPEDITIONS
7 TW ANTENNAS TW2010 TRAVELER The TW Antennas TW2010 Traveler antenna is similar in design to the Force-12 Sigma-5. The notable differences are in the height of the antenna (the Traveler is shorter), the length of the arms (the traveler has longer arms), the diameter of the elements (the Traveler uses one inch aluminum tubing for all elements), and the control mechanism (the Traveler has a electronics control package that can perform automatic band switching when connected to a radio). Both antennas use loading coils and relays to select the combination of coils in use. Both antennas sit relatively low to the ground and depend on the large capacity hats to provide good efficiencies and matches on the five supported bands. The TW Antennas TW2010 Traveler is a relatively new antenna as of this writing. The analysis below shows that it is competitive with the Force-12 Sigma-5 with performance down 0.7 to 1.5 dB from the Force-12 offering. The take-off angle of the Traveler also rises about 5 degrees from the Force-12. Still, the TW Antennas Traveler packs and travels better than the Force-12 Sigma-5, and deployment is easier than the Sigma-5 with no tools (and no bolts) assembly. The next few sections will discuss the TW Antennas TW2010 Traveler antenna. As with the Force-12 Sigma-5, the various bands will be treated as different antennas though they all use the same physical structure. Band changes indicate a change in the loading coils; band changes do not require any other physical changes to the antenna. 7.1
TW Antennas TW2010 Traveler on 10 meters The TW Antennas Traveler model is nearly identical to the Force-12 Sigma-5 with just a few things changed. Like the Force-12 Sigma-5, the TW Antennas Traveler has a matching stub (coil) to counteract the large capacitance from the arms. The details of this stub follows. Name
Diameter
Number of turns
Length
XL
Stub
0.65
4
1
0.37 ÂľH
The methodology for determining this value is described in the next section. Here are the model details for the TW Traveler antenna including the loading information for 10 meters. EZNEC+ ver. 5.0 TW Antennas Traveler
8/29/2007
3:54:19 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1 --------------- WIRES --------------No.
End 1 Conn.
Coord. (in) X
Y
End 2 Z
1
W2E1
0,
0,
20
2
W3E1
0,
0,
20
Conn. W4E1
Coord. (in)
Dia (in)
Segs
Z
Diel C
Ins
X
Y
Thk(in)
0,
0,
100
1
30
1
0
0,
-30,
20
1
11
1
0
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