Subj : Growing Loft to Roof Aerials
To   : WW
From : G8MNY
Date : Sat Aug 31 2019 11:04 pm

G8MNY    TECH     31.08.19 06:15l 111 Lines 5337 Bytes #365 (0) @ WW
BID : 19583_GB7CIP
Subj: Growing Loft to Roof Aerials
Path: OK0NBR F3KT OK0NAG DB0ERF DB0RES DB0OVN DB0GOS ON0AR GB7CIP
Sent: 190831/0904Z @:GB7CIP.#32.GBR.EURO #:19583 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                             (New Nov 09)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
When I started AR in 1977 as a VHF & above ham, I used a loft aerial system
that grew & grew.

              n
            / Þ \Roof           I put a pole loft floor to roof
          /   Þ   \             & eventually I found I had enough
        /     Þ     \           space to fit a homebrew 6 el 2m quad.
      /. [-[-[Þ[-[-[].\         The vertical pole with a rotator at
    /   ú     Þ     ú   \       the bottom meant lots of
  /      '.   Þ   .'      \     experimenting was possible.
/__________ú__±±_ú__________\
 Loft floor   Rot

                                         n
For vertical polarisation              / Þ \
& working satellites I               /   Þ   \
put a horizontal broom             /     Þ     \
handle on the pole & ganged      /.  [-]-Þ--X   .\
the 2m quad with 70cm          /   ú     Þ     ú   \
46 element multibeam.        /      '.   Þ   .'      \
                           /__________ú__±±_ú__________\

There was quite a bit RF loss through the roof so I decided to grow the pole &
pushed it out through the roof.

 2M Quad [-[-[-Ý]-]-]            As you see I put the extension 16ft pole
              nÝ                 alongside with large clamps. The roof
            / ÞÝ\                hole goes through a sheet of ally with an
          /   ÞÝ  \              oval hole in it, so the pole side forces
        /     ÞÝ    \            are not taken by the drilled tile hole.
      /.      ÞÝ     .\          The coax down the roof tube is free to do
    /   ú     ÞÝ    ú   \        what to needs to rotate. The 2" offset
  /      '.   Þ   .'      \      eccentricity is irrelevant on the loft
/__________ú__±±_ú__________\    pole & rotator.

                                    Roof Pole
                                       ³Þ³   Ridge
                                Funnel/³Þ³\ /~\
                                       ³Þ³-~   ~-_
For water proofing,              Roof  ³Þ³-~Ally
I put a large beer                  _-~³Þ³Plate
funnel on the pole               _-~ -~³Þ³
above the hole & also           ~     {³Þ³³ ³} Large
placed the rotator in                  ³Þ³³ ³  Clamps
a large drip tray to                  {³Þ³³ ³}
to catch the leaks.                     Þ ³ ³
                                   Coax Ý ³ ³
                                       Þ  ~ ³
                                       Ý  ³ ~
                                      Þ   ³ ³
                                      Ý   ²²² Rotator
                                Drip     ±±±±±
                                Tray³____±±±±±__³  Loft Floor
                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To my surprise I did not have any complaints from the neighbours or planners
with the outside aerial! (would not be true today!)

Later I lifted it as high as I dare (moving the funnel down), but I noticed
some swaying in windy Wx. So I then designed & added some guys on a top
bearing.

       Pole                                 Guy  ú
        ³ ³ Cast Guy                        Wireú    _-~
   Guy_ÚÄÄÄ¿-plate                             ú  _-~
Eyelet.øÝ Þø.                             Tube/_-~ Roof
     ú  ³ ³\__Cast clamp                   ‡Ú/~--------Gutter
   .'   ³ ³   & Nylon Washer                '~³~~~~~~~~~~
  úGuys ³ ³                                   ³

These plastic covered steel guy wires are anchored on the 4 corners of the
house with a 7mm dia plastic covered flexible thin ally low pressure tube. The
wire is threaded through the tube & the tube bent around the masonry to "grab
it", this stops any wire chaffing & the wire length can be adjusted a few
inches & the ends loosely twisted together to finish off.

                                              _
Later I found that 4 guys           ÚÄÄÄÄÄÄÄÄÁÄÁÄÄÄÄÄÄÄÄ¿
was not enough & the                ³~-_      |      _-~³
pole folded in a storm.             ³   ~-_   |   _-~   ³
                                   ÚÁ¿     ~-_|_-~     ÚÁ¿
So I redesigned it to have         ³ ³~~~~~~~-ø-~~~~~~~³ ³
8 guys (used chimneys too)         ÀÂÙ   _-~  | ~-_    ÀÂÙ
& put it up higher with             ³ _-~     |    ~-_  ³
more & larger aerials on it too.    ÀÄÄÄÄÄÄÄÄ¿|       -_³
                                             ÀÄÄÄÄÄÄÄÄÄÄÙ


            ////////////////////////            I ended up with a 24el on
                       ³                        23cm for ATV & 19el for 70cm
       /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/    & an 8el 2m homebrew dual
      / / / / / / / / /Ý/ / / / / / / / / /     boom quad.
   ,     ,     ,     , Ý   ,     ,     ,     ,  The 23 & 70cm aerials on stub
  /³   _/³____/³____/³_Ý _/³   _/³   _/³   _/³  masts are fed with the large
 /~³~~~/º³~~~/~³~~~/~³±Ý~/~³~~~/~³~~~/~³~~~/ ³  LDF450 coax & that goes down
³  ³  ³ º³  ³  ³  ³  ³±Ý³  ³  ³  ³  ³  ³  ³  ³  the thin walled 2" 16ft roof
³ /   ³_º/  ³_/   ³_/ ±Ý³_/   ³_/   ³_/   ³_/   pole & it does 2 large turns
³/~~~~³/~~~~³/~~~~³/~~±~³/~~~~³/~~~~³/~~~~³/    in the loft space so that the 
'     '     '     ' úß±ßú     '     '     '     whole lot can easily rotate.
                  .'  ±  '.


Why don't U send an interesting bul?

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