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

["Graham" <g8fzk@g8fzk.fsnet.co.uk>]

, well  at   40  ft  + the  insulated  base  ,   making   46  ft   above the  ground  , I think its  high  enough ! , its only a  few feet  from the back  wall  , so  guying  is a  problem  with the  shallow angle  .....  I may  be able to  get  a  triangle    40x40x10 ft base up , quite  simply  , after  that  its a  big job

 

73-G,

 

ps    http://uk.groups.yahoo.com/group/airspy/  a  new  megga  dongle is  in development  , from the  sdr-sharp  gang

From: M0FMT

Sent: Tuesday, December 03, 2013 10:35 PM

To: rsgb_lf_group@blacksheep.org

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

 

Graham and extra pole is not unreasonable or by adding a smaller diam. light weight pole 20ft on top. Check it out another 'S' point (or thereabouts) for free? Paint it mottled blue and the neighbours wouldn't even notice. You know it makes sense. GL.

73 es GL Pete M0FMT IO91UX

On Tuesday, 3 December 2013, 21:39, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:

Err   NCD on that  one  Pete , the  last  'refurbishment'  of the  pole  , attracted  evil spirits ...so at   2x 20  2 inch alloy scaffold poles , that's as  good  as  it  get's  !

 

73-G,

From: M0FMT

Sent: Tuesday, December 03, 2013 9:13 PM

To: rsgb_lf_group@blacksheep.org

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

 Hi Graham

Probably better to put your efforts into making it higher ?

73 es GL Pete M0FMT IO91UX

On Tuesday, 3 December 2013, 11:25, Alan Melia <alan.melia@btinternet.com> wrote:

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,