Wimo 70 cm X-Quad Antenna

This page describes the X-Quad, an antenna for the 70 cm band manufactured by Wimo. The reader will be guided through the assembly process step-by-step, and finally I'll describe my experience using it.

How to assemble the antenna

Please refer to the numbers in the photo. You can click on any photo to enlarge it. 
The quad-element (1) is fitted with two female N-connectors. The plastic bag (2) contains brackets, nuts, screws, washers, and other hardware. Parts of the antenna boom is visible at (3). In the upper part of the photo (4), 12 director elements and 2 reflector elements are visible. 

Element holders and other hardware.
Screws, washers, nuts, element holders
There are 16 element holders (1) in total, each with matching M5 screw, lockwasher, and nut. 

The self-tapping screw (2) will help fasten the quad-element to the boom. 

Two big washers (3), two wing nuts (4), and two M6 screws (5) plus two washers from the pile (6) will be used for the mast clamp. Remaining parts belonging to the mast clamp are not in the photo. 

Center of the quad element.
Quad element
This photo shows the center of the quad element. The two N-connectors are designed for easy change of polarization. By using connector 1a, horizontal polarization is achieved. Connector 4a provides vertical polarization. LHCP or RHCP is achieved using both connectors and a phase cable.

The center pin of connector 1a is connected to alu-band 1. The center pin of connector 4a is connected to alu-band 4. Alu-band 2 must be fastened to the boom using a self tapping screw. Alu-band 3 is factory-mounted. 

The two factory-mounted screws (5) penetrate the alu-box and are intended for going through two holes in the boom. The two screws (5) are fixed and cannot be turned. 


The quad elementet mounted on the boom.
Mounting the quad element 
The quad element is attached to the boom using two lockwashers and two M5 nuts(1). The self tapping screw (2) is used for fastening the alu-band to the boom. But before doing that, a new hole was drilled - the factory made hole was not properly placed. 

Fitting the quad element can be a challenge. Be patient, and do not use excessive force!

The quad element is attached to the boom.
The quad element attached
This photo shows how the quad element is attached to the boom. 

Reflector; part 1/2
The reflector elements are mounted on the element holders and fastened by a screw, a lockwasher, and a nut. The element holders are mounted closest to the boom. The element holders secure, that the reflector elements are kept properly in place. 

Mounting sequence:

nut - lockwasher - reflector element - element holder - boom - element holder - reflector element - screw

Reflector; part 2/2
This photo shows the reflector from a different angle. The two element holders are mounted on the boom and they keep the two reflector elements in place. 

All director elements are mounted in the same way. 

Mast clamp; step 1/3
First step is to put the U-bolt through the two holes in the fixed clamp. 
Mast clamp; step 2/3
The second step is to mount the boom clamp (marked Wimo) on the fixed clamp using two M6 screws. 
Mast clamp; step 3/3
The third step is to add the latch to the U-bolt. Add two M6 big washers, and finally two M6 wing nuts. Done!

The finished X-Quad antenna The finished antenna with phasing lines. 
The finished antenna.Close-up of the finished antenna.
The longest phasing line is connected to the leftmost N-socket to obtain RHCP.

Antenna performance 

Performance of the new X-Quad was evaluated using my old 70 cm yagi as reference antenna. The old antenna is the 6EL70 (6 element yagi with 10 dBd gain) from Vårgårda Radio in Sweden. The gain of the new X-Quad is 12.8 dBd according to the manufacturer.

The evaluation was carried out at my QTH in Holstebro (JO46gi). Both antennas were 7 m above ground level and a mast-mounted pre-amp was used.

Object to receive 6-el yagi (horizontal)  18-el X-Quad (RHCP)
Beacon OZ7IGY 
432.471 MHz, distance 227 km
Always audible (100 %). Same.
Beacon DB0VC
432.420 MHz, distance 273 km
Audible most of the time (90%). Same.
FO-29 satellite 
Downlink 435.850 MHz CW/SSB 
Audible with some fading No fading on reception.
Good signal strength when satellite elevation < 30 degrees.


As you can read in the table above, satellite performance is improved. The satellite reception is better because fading due to polarisation mismatch is virtually absent. For satellite work I can recommend this antenna. Terrestical work is another matter where a long horizontal yagi for CW/SSB/WSJT would be a good choise and deliver better performance for the same money due to higher gain and a less bulky antenna.

Written by OZ1BXM Lars Petersen 22-May-2007. Latest revision August 2nd, 2010.