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
/ ▐ \Roof I put a pole loft floor to roof
/ ▐ \ & eventually I found I had enough
/ ▐ \ space to fit a homebrew 6 el 2m quad.
/. [-[-[▐[-[-[].\ The vertical pole with a rotator at
/ · ▐ · \ the bottom meant lots of
/ '. ▐ .' \ experimenting was possible. /__________·__▒▒_·__________\
Loft floor Rot

n
For vertical polarisation / ▐ \
& working satellites I / ▐ \
put a horizontal broom / ▐ \
handle on the pole & ganged /. [-]-▐--X .\
the 2m quad with 70cm / · ▐ · \
46 element multibeam. / '. ▐ .' \
/__________·__▒▒_·__________\

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 [-[-[-▌]-]-] As you see I put the extension 16ft pole
n▌ alongside with large clamps. The roof
/ ▐▌\ hole goes through a sheet of ally with an
/ ▐▌ \ oval hole in it, so the pole side forces
/ ▐▌ \ are not taken by the drilled tile hole.
/. ▐▌ .\ The coax down the roof tube is free to do
/ · ▐▌ · \ what to needs to rotate. The 2" offset
/ '. ▐ .' \ eccentricity is irrelevant on the loft /__________·__▒▒_·__________\ pole & rotator.

Roof Pole
│▐│ Ridge
Funnel/│▐│\ /~\
│▐│-~ ~-_
For water proofing, Roof │▐│-~Ally
I put a large beer _-~│▐│Plate
funnel on the pole _-~ -~│▐│
above the hole & also ~ {│▐││ │} Large
placed the rotator in │▐││ │ Clamps
a large drip tray to {│▐││ │}
to catch the leaks. ▐ │ │
Coax ▌ │ │
▐ ~ │
▌ │ ~
▐ │ │
▌ ▓▓▓ Rotator
Drip ▒▒▒▒▒
Tray│____▒▒▒▒▒__│ 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 ·
│ │ Cast Guy Wire· _-~
Guy_┌───┐-plate · _-~
Eyelet.°▌ ▐°. Tube/_-~ Roof
· │ │\__Cast clamp ç┌/~--------Gutter
.' │ │ & Nylon Washer '~│~~~~~~~~~~
·Guys │ │ │

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 ┌────────┴─┴────────┐
was not enough & the │~-_ | _-~│
pole folded in a storm. │ ~-_ | _-~ │
┌┴┐ ~-_|_-~ ┌┴┐
So I redesigned it to have │ │~~~~~~~-°-~~~~~~~│ │
8 guys (used chimneys too) └┬┘ _-~ | ~-_ └┬┘
& put it up higher with │ _-~ | ~-_ │
more & larger aerials on it too. └────────┐| -_│
└──────────┘


//////////////////////// I ended up with a 24el on
│ 23cm for ATV & 19el for 70cm
/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ & an 8el 2m homebrew dual
/ / / / / / / / /▌/ / / / / / / / / / boom quad.
, , , , ▌ , , , , The 23 & 70cm aerials on stub
/│ _/│____/│____/│_▌ _/│ _/│ _/│ _/│ masts are fed with the large
/~│~~~/║│~~~/~│~~~/~│▒▌~/~│~~~/~│~~~/~│~~~/ │ LDF450 coax & that goes down
│ │ │ ║│ │ │ │ │▒▌│ │ │ │ │ │ │ │ the thin walled 2" 16ft roof
│ / │_║/ │_/ │_/ ▒▌│_/ │_/ │_/ │_/ pole & it does 2 large turns │/~~~~│/~~~~│/~~~~│/~~▒~│/~~~~│/~~~~│/~~~~│/ in the loft space so that the ' ' ' ' ·▀▒▀· ' ' ' whole lot can easily rotate.
.' ▒ '.


Why don't U send an interesting bul?

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