In tuning up any antenna system, I like to start out by tuning up the transmitter to a suitable dummy load, :or example, with low power, a 40-watt oven bulb (the clear glass makes the filament easier to see than on a frosted bulb). As the first step it is always nice to know that the transmitter is putting out power.
Next, let's tune up on 28 MHz- Remove the dummy load from the transmitter and hook up the coax to the tuner. Place the clips on the tuner coil in approximately the position shown in the photograph.
Set condenser C2 at approximately one-half capacity (assuming 150 pfh
Adjust the load controls on the transmitter so that meter readings indicate the antenna appears to be taking some power. Now rotate CI, and watch for the bulb to light. If it does not, throw the switch, and try again. If you still get no indication (chances are you will) move the clips either closer to the center, or further out, Try to have the same number of turns on both sides.
You may make a few false starts, but in a couple of minutes you should arrive at a point where tuning condenser CI through resonance will cause the bulb to light. Now adjust C2 for maximum brightness of the indicator bulb, and "touch up" the tuning of the transmitter. The name of the game is to achieve maximum brightness on the indicator bulb without, of course, overloading the transmitter — which probably has a plate milliameter to indicate proper input.
If you want to insert an swr meter into the coaxial line, now is the time to do it — and chances are very, very good that the swr will be quite low, although careful adjustment of C2 may bring it still lower.
Once you have discovered the proper tap points for 10 meters, indicate them with a dab of paint (or finger nail polish) alongside the clips so that it will be easy to return to the same spot.
Tune up on 15 meters and 20 meters follows exactly the same procedure. When you have maximum brilliance on the bulb you have the system in resonance and virtually a written guarantee that you will it get out. Additional Bands?
Yes, the Mini Vee will tune up on the
Was this article helpful?