Rule of thumb...The higher you place the loading coil on the tower
before the horizontal top loading wire, the more efficient the antenna
will be. If the coil is at the top and then connects to a top loading
wire you solve several problems. If the wire end is brought temporarily
near the ground if can be punned for resonance of the vertical. This
will avoid having to go up avoid you having to adjust the coil. Also an
old trick was to tape a #47 light bulb with a few turns at the junction
at the top of the tower. Feed a few watts in the evening till you get
visible illumination then start trimming the end of the wire. If the
light gets brighter you are going in the right direction but if it dims
just add more wire till it gets to its brightest point. You might need
a series cap at the base to tune out any reluctance. Or an MFJ-259 will
tell you how much fixed capacitance to put in. If the MFJ tells you at
the base you need some ore inductance a simple L network can deal with that.
Herb Schoenbohm, KV4FZ
On 1/8/2016 7:09 PM, w5jmw@towerfarm.net wrote:
Hello to all.I am planning a 60 foot vertical.I am wanting to either
place a coil on the vertical for topband.The vertical is a hy-tower.I
have base loaded(not very effective) I have toploaded with a single
wire(not enough room).I now have plenty of room.So my question.
Base load with many radials,60+
top load at the highest with wires?
top load with coil? and if this is best where should the coil be placed.
thanks to all es 73 john w5jmw
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