Maco Antennas M103C Assembly Instructions Manual - page 4

ASSEMBLY INSTRUCTIONS

(continued)

FIGURE 4

GAMMA MATCH MOUNTING

Mount the gamma match 

 to the driven element, using the gamma straps 

 and

attaching hardware as shown. Attach your 52 ohm coaxial cable to the connector (S42) and dress along boom

and down the mast. The gamma is shown pointing down   this is to let water out.

ADJUSTING THE STANDING WAVE RATIO 

Refer to Figure 4. The dimensions given are approximate and should be used as a starting point. The

gamma match has 2 adjustments. First is the capacitor adjust and second is the slider adjust. Connect a SWR

bridge coax between your transmitter and the antenna and check the SWR. If adjustment is required, loosen

the clamp on the gamma match and the screws holding the slider (gamma straps 

 Next move the

capacitor adjustment first one direction, then the other until a minimum 

 is obtained. If SWR

is not yet satisfactory, move the slider out 2” away from the boom. If the reading has gone up move the slider

back to the original position and then 2” towards the boom. Now readjust the capacitor for minimum SWR.

You shouldnow be able to determine which direction to move the slider. Repeat the aboveproceduremoving

the slider in smaller increments until a satisfactory SWR is obtained. Tighten all hardware. Disconnect the

SWR bridge and reconnect your coaxial cable.

NOTE!

When assembling for vertical use, set antenna on a pole about 8 to 9 feet above the ground

horizontally and adjust SWR for 1.7. When you turn the antenna vertical and mount it on the tower, etc.,

the SWR will drop to 1.5 or less . This is good; QUIT!