308 Industrial Park Road
Starkville, MS 39759 USA
Ph :
(662) 323 -953 8 FAX: (662) 323 -6551
DX-77A
7-Band HF Vertical
10, 12, 15, 17, 20, 30, 40-Meter
I N S T R U C T I O N M A N U A L _
General Description
The "DX-77-A" is an omnidirectional, self-sup-
porting, automatic-bandswitching vertical
radiator which operates on the 10, 12, 15, 17, 20,
30 and 40 meter Amateur bands. No ground
radials are used with the DX-77-A. The DX-77-A
design is based upon an off-center-fed dipole,
sometimes called a "Windom" antenna. High-
efficiency high-power traps are used to isolate
the active sections of this antenna.
The DX-77-A uses a heavy-duty tiltable mast
clamp which will accept masts of up to 2 118"
inches O.D. The entire antenna may be easily
raised and lowered for tuning purposes and for
recreational - vehicle (RV) installations. The
DX-77-A also features an overall length of 29
feet (8.8 m), which contributes to exceptional
bandwidths on 40 and 20 meters.
Specifications
Electrical.
Frequency
Bands:
2:1 VSWR Bandwidth
40m
7.0 - 7.3 MHz
100 KHz min.; 150' KHz typ.
30m
10.1 - 10.15 MHz
100' KHz min., 150 KHz tpy.
20m
14.0 - 14.35 MHz
200 KHz min., 250 KHz typ.
17m
18.068 - 18.168 MHz
200 KHz min., 250: KHz typ.
15m
21.0 - 21.45 MHz
400 KHz min., 500 KHz typ.
12m
24.89 - 24.99 MHz
300 KHz min., 400 KHz typ.
lom
28.0 - 29.7 MHz
1500 KHz min., 1700 KHz typ.
VSWR' of Resonance............................. .. .....................................................less than. 1.5:1
Maximum Power (at 95° F) ............................................ 750 watts ave., 1500 watts PEP
Gain..... . ........................................unity gain (compared to half-wave vertical dipole)
Input Impedance
.....................................................................................................50
ohms
Mechanical:
Total Height.……........................ ......................................................... 29 feet (8.8'
m)
Bottom Radial Elements .........................................................................4 each, 5 feet (1.5 m)
Allowable Mast O.D. . .....................
................................1.75 - 2.125 inches (44
-
53
mm)
Recommended Masts8 to 10 foot length) .....…........ Aluminum, 2 inch O.D.,
.125
wall
min
Steel, 2 inch O.D., :058 wall min.
Weight................... ... ............................................……………………... 25 lbs. (11.35 kg:)
Wind Area . ... .... ............. ....'..............………………………........
1.9
sq. ft. (.1767 sq. m.)
Maximum Wind Speed (unguyed) ........................................................ 60 mph ( 96.77 Kmph)
