LF: Re: Inv L 'FAN' top wires ?

["Alan Melia" <alan.melia@btinternet.com>]

Hi Graham, this will increase the aerial capacity by around 100 to 120pF provided the new wires are not over/close to lossy foliage/buildings, as the new wires are only the same length as the current wires you will see little increase in Rrad, BUT you will see a proportional decrease in the loss resistance. So the aerial becomes more efficient......this assumes a flat fan not a sloping one. 

 

There is also mileage to be had by connecting the ends of the fan together!! see the measurements Finbar did on the Spiral top loaded systems we tested. http://g3nyk.ham-radio-op.net/spiraltop.htm

 

Approximately, doubling the antenna capacitance halves the  Rloss which is the component determining the antenna current you can drive and hence the ERP.

 

Alan

G3NYK

----- Original Message -----

From: Graham

To: rsgb_lf_group@blacksheep.org

Sent: Tuesday, December 03, 2013 12:20 AM

Subject: LF: Inv L 'FAN' top wires ?

 

Anyone   tried  this  configuration  ?

 

Changing  single   40 ft  top   wire  on inv-L    to  a   FAN

shape  x3 40 Ft  , spaced  about  10 ft  at  far  end   

 

TNx -G,