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G8MNY > TECH 12.05.26 15:51l 111 Lines 5345 Bytes #8 (0) @ WW
BID : 59500_GB7CIP
Subj: Growing Loft to Roof Aerials
Path: JH4XSY<N3HYM<GB7YEW<GB7CIP
Sent: 260512/0650Z @:GB7CIP.#32.GBR.EURO #:59500 [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
/ ﾞ \Roof I put a pole loft floor to roof
/ ﾞ \ & eventually I found I had enough
/ ﾞ \ space to fit a homebrew 6 el 2m quad.
/. [-[-[ﾞ[-[-[].\ The vertical pole with a rotator at
/ � ﾞ � \ the bottom meant lots of
/ '. ﾞ .' \ experimenting was possible.
/__________銈_ｱｱ_銈_________\
Loft floor Rot
n
For vertical polarisation / ﾞ \
and working satellites I / ﾞ \
put a horizontal broom / ﾞ \
handle on the pole & ganged /. [-]-ﾞ--X .\
the 2m quad with 70cm / � ﾞ � \
46 element multibeam. / '. ﾞ .' \
/__________銈_ｱｱ_銈_________\
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 [-[-[-ﾝ]-]-] As you see I put the extension 16ft pole
nﾝ alongside with large clamps. The roof
/ ﾞﾝ\ hole goes through a sheet of ally with an
/ ﾞﾝ \ oval hole in it, so the pole side forces
/ ﾞﾝ \ are not taken by the drilled tile hole.
/. ﾞﾝ .\ The coax down the roof tube is free to do
/ � ﾞﾝ � \ what to needs to rotate. The 2" offset
/ '. ﾞ .' \ eccentricity is irrelevant on the loft
/__________銈_ｱｱ_銈_________\ pole & rotator.
Roof Pole
ｳﾞｳ Ridge
Funnel/ｳﾞｳ\ /~\
ｳﾞｳ-~ ~-_
For water proofing, Roof ｳﾞｳ-~Ally
I put a large beer _-~ｳﾞｳPlate
funnel on the pole _-~ -~ｳﾞｳ
above the hole & also ~ {ｳﾞｳｳ ｳ} Large
placed the rotator in ｳﾞｳｳ ｳ Clamps
a large drip tray to {ｳﾞｳｳ ｳ}
to catch the leaks. ﾞ ｳ ｳ
Coax ﾝ ｳ ｳ
ﾞ ~ ｳ
ﾝ ｳ ~
ﾞ ｳ ｳ
ﾝ ｲｲｲ Rotator
Drip ｱｱｱｱｱ
Trayｳ____ｱｱｱｱｱ__ｳ 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 �
ｳ ｳ Cast Guy Wire� _-~
Guy_ﾚﾄﾄﾄｿ-plate � _-~
Eyelet. ﾞ�. Tube/_-~ Roof
� ｳ ｳ\__Cast clamp �ﾚ/~--------Gutter
.' ｳ ｳ & Nylon Washer '~ｳ~~~~~~~~~~
ⅷuys ｳ ｳ ｳ
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 and the tube bent around the masonry to "grab
it", this stops any wire chaffing and the wire length can be adjusted a few
inches & the ends loosely twisted together to finish off.
_
Later I found that 4 guys ﾚﾄﾄﾄﾄﾄﾄﾄﾄﾁﾄﾁﾄﾄﾄﾄﾄﾄﾄﾄｿ
was not enough & the ｳ~-_ | _-~ｳ
pole folded in a storm. ｳ ~-_ | _-~ ｳ
ﾚﾁｿ ~-_|_-~ ﾚﾁｿ
So I redesigned it to have ｳ ｳ~~~~~~~-�-~~~~~~~ｳ ｳ
8 guys (used chimneys too) ﾀﾂﾙ _-~ | ~-_ ﾀﾂﾙ
& put it up higher with ｳ _-~ | ~-_ ｳ
more & larger aerials on it too. ﾀﾄﾄﾄﾄﾄﾄﾄﾄｿ| -_ｳ
ﾀﾄﾄﾄﾄﾄﾄﾄﾄﾄﾄﾙ
//////////////////////// I ended up with a 24el on
ｳ 23cm for ATV & 19el for 70cm
/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ and an 8el 2m homebrew dual
/ / / / / / / / /ﾝ/ / / / / / / / / / boom quad.
, , , , ﾝ , , , , The 23 & 70cm aerials on stub
/ｳ _/ｳ____/ｳ____/ｳ_ﾝ _/ｳ _/ｳ _/ｳ _/ｳ masts are fed with the large
/~ｳ~~~/ｺｳ~~~/~ｳ~~~/~ｳｱﾝ~/~ｳ~~~/~ｳ~~~/~ｳ~~~/ ｳ LDF450 coax and that goes down
ｳ ｳ ｳ ｺｳ ｳ ｳ ｳ ｳｱﾝｳ ｳ ｳ ｳ ｳ ｳ ｳ ｳ the thin walled 2" 16ft roof
ｳ / ｳ_ｺ/ ｳ_/ ｳ_/ ｱﾝｳ_/ ｳ_/ ｳ_/ ｳ_/ pole & it does 2 large turns
ｳ/~~~~ｳ/~~~~ｳ/~~~~ｳ/~~ｱ~ｳ/~~~~ｳ/~~~~ｳ/~~~~ｳ/ in the loft space so that the
' ' ' ' 朎ｱﾟ� ' ' ' whole lot can easily rotate.
.' ｱ '.
Why don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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