Fw: TopBand: shunt-fed feeding ??

[Donald B. Hall]

----------
> From: 
> To: topband@contesting.com; JOHN M WEBB <ko5d@juno.com>
> Subject: Re: TopBand: shunt-fed feeding ??
> Date: Wednesday, November 19, 1997 8:43 PM
> 
> John,
> 
> I have had good luck with a simple drop wire with a series capacitor
> tuned for resonance.
> 
> Depending on the size of the drop wire, the height of the feed point
> and the spacing of the drop wire from the tower, the resistance at
> resonance gives an SWR of 2 to 2.5.
> 
> You can then feed with 50 ohm coax and use the tuner in the shack.
> 
> The drop wire has to be less than a quarter wave long electrically so
> you see an inductive reactance at the bottom to tune with the series
> capacitor.
> 
> I have used this method for some ten years at the 1500 watt level with
> good results. I started with vacuum variables but recently replaced them
> with fixed transmitting ceramics for the 75/160 meter feeds. I feed three
> drop wires for 75/80/160 on the three corners of the tower and switch
with
> an Ameritron remote antenna switch at the tower base.
> 
> Good Luck
> 
> Don K5AQ
> 
> 
> ----------
> > From: JOHN M WEBB <ko5d@juno.com>
> > To: topband@contesting.com
> > Subject: TopBand: shunt-fed feeding ??
> > Date: Wednesday, November 19, 1997 5:48 PM
> > 
> > Well I have the tower shunt-fed.I have done this in past and not had
very
> > good results but thought I'd try again.I am feeding the gamma rod at
the
> > 100 foot level,above that is a 2 element 40 meter yagi,above that is a
> > mosely tribander,then a 13 ele vhf ssb yagi then a vhf vertical.My
> > question is,I dont want to match it at the base,I have 2 heathkit 2060a
> > tuners that have worked well in past and handle the power I am running
> > ok...
> > 
> > CAN I MATCH INSIDE THE HOUSE WITH A TUNER ???
> > WHAT KIND OF FEELINE SHOULD I RUN ??
> > CAN I USE A REMOTE BALUN AND FEED WITH COAX ??
> > 
> > These are present questions I have.So far I have 4 radials connected to
> > ground point.I am adding more each day,hi.I realize the more I add the
> > better,and also that to a point it will effect my match.These questions
> > may sound elementary to some but,I would like to try to make this
> > work.I've always had good luck with inverted vees at the 100 ft
level,and
> > can go back to that if I must but,with the tower situation I have I
feel
> > that I must rty this.I am currently getting a match with the tuner and
> > running 50 ohm coax line from the long wire terminal and gnd to the
> > antenna but of course having a very high voltage point in tuner,some
> > arcing at power levels above 500 watts.
> > suggestions and comments greatly appreciated and to all 73 ...john,KO5D
> > 
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