YU1QT "Andra" has fashioned a 6 band MOXON hybrid antenna. His antenna covers 6, 10, 12, 15, 17 and 20 meter ham bands. Each of the 6 elements are steel wire 1mm diameter PVC covered... the kind often used for outdoor laundry drying. His spreaders are Chinese manufactured 6 meter long fishing poles. The end's of each spreader are connected with 2mm nylon line to a top of the mast for stability. Andra also uses short lengths of nylon line to separate the ends of the driven and reflector elements. Each driven element is separately fed with RG-6, 75 ohm's TV coax. Andra prefers TV coax over RG-213 for better impedance match and far less cost. He calculates that each elements feed point impedance to be about 80 -100 ohm's impedance.
Andra has used his 6 band MOXON with great success for the last 2 years. The antenna is easily rotated with a light duty TV rotor. He reports no interaction between his MOXON and other antennas mounted on the same mast.
Andra likes his MOXON for the following reasons:
- Extremely low noise
- Very directional for just two elements on each band
- Superior front to back rejection
- Inexpensive
- Much lighter in weight than a comparable tri-band yagi or quad
Here are the detailed specifications for Andra's MOXON:
T= total length incl. (A + D+ 2F(ront) +2B(ack) +2E(distance's between driver and reflector)
A = D = Total length (T) / 4 = (F + E + D)
CAUTION: DRIVER elements are LONGER than REFLECTOR elements!!
Every wire is attached to the spreaders with cable tie. (BLUE)
Also, same tie point's on 20m antenna are connected with rope on top of mounting, in center of antenna. If you expect very strong wind, put one complete of ropes .5m down on mounting center.
Mounting is a barrell, 40-50mm in diameter of PVC (76mm outside diameter with a 10mm wall thickness), about 2m long.
Fishing rod spreaders must be 6m long (using,first 4 segment's). For “Chineese made” rod's, drill 4 holes 28mm diameter,1m down from the top, in 90 degrees (cross); one above other. Insert the “broomstick” handle piece through these holes (just 28mm,real) about 60-70cm in length. On that broomstick handle's, put fishing rod's without cap's.
Dimensions for I5XFW 20m example:
DRIVER = 10.45m
(F=2x2.29m)
REFLECTOR = 10.17m
(B=2x2.15m)
DISTANCE (E) = 2x 1.46m(rope)
TOTAL= 23.54m ;(1.5mmsq. Copper wire in PVC)
Thanthal CONDENSATOR 2KV(C)= 200pF
TF COAX 75 ohm(QUARTER LENGTH) LINE, v.f.0.8 for 20m band= 4.24m
Detail C-C:
Similar to detail B-B, but without extended length of 15 cm.
CAUTION: All diagram's are shifted in frequency due to so called ”skin effect”, velocity factor PVC coated Copper wire. So, 14,500 MHz = 14,000MHz IN REAL, on mast ; Also,21,600 MHz = 21,000 Mhz; etc!!!
DIMENSION's :
Insulated copper wire (PVC) ; 1.5mm.sq
14 18 21 24 28
A = D = 5.87 4.21 3.675 3.12 2.75
F = 2.29 1.915 1.70 1.4 1.29
B = 2.15 1.885 1.63 1.35 1.24
E = 0.73 0.22 0.18 0.19 0.11
C = 200pF no 150pF 88pF 66pF
T = 22.08m 16.46m 14.37m 12.12m 10.78m
Tf. line,75 ohm's; with v.f. 0.8;
for 20m band = 4.24m;
for 17m band = 3.76m;
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6 band VERSION dimension for 50,1 Mhz:
A = D = 1.7m
F = 0.68m
B = 0.64m
E = 0.38m
C = 24pF
T = 6.8m
Tf. line, 75 ohm's; with v.f. 0.8; = 0.56m
Andra is a 50 years old musician who has been a ham since 1999. He operates with an ICOM IC-706 and his 6 ban Band Moxon from the capitol city of Belgrade in Yugoslavia. His wife "YZ1BBP", son "YT1DAT" and daughter in law "YT1JEL" also enjoy amateur radio. Andra operates mainly on 17 meters.
Email YU1QT "Andra" at muzikant@sezampro.yu for additional information about his 6 band MOXON.
