Topband: placement oc coil

[Herbert Schoenbohm]

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 at 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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