Pelican Wireless Mast

Pelican is located in Ruse Street, Osborne Park. This is on top of a small hill, surrounded by Innaloo, Doubleview, Floreat, Glendalough. The GPS co-ords are: 31* 54' 28.5" S, 115* 48' 57.1" E.

Pelican is my family business. The landlord is happy for me to put up a mast and make whatever changes I want. This is in an industrial zone; there are no height restrictions on masts here (normally 9 metres in residential areas, unless you have council permission for higher).

My goal is to have a link from my house, 2.4 kms away, to the office. To do this, I need a mast on the office end to get over some of the closer buildings. With this mast in place, I am free to get other things on the mast.

What I propose is this: if I can get a resonably good confidence that it will work, then I can get Pelican to pay for the mast (I have heard of second hand, 3 metre lengths of ex-Telstra tripple pole, latticed mast for $50 per length). With four lengths, I get 12 metres.

You can see the roof as it is now.

I hope to put a four-way guy line from the mast into the brick walls of the building. The main roof structure is asbestos (agh!). However, there is a brick wall running up the middle of the building, right under where I want to position the mast!

I am pretty sure we can supply power to e3 and mast space for nothing. I just need some help in getting the mast set up.

March 7th 2002

Did a trip to Hills Antenna today, looking at teloscopic masts, in place of rigid segments. Telescopics are supposedly going to be easier to erect, but are not climable. Probably just as well, I'd get too scarred climbing 15 metres of mast.

Problem one seems to be solved: how to attach the base to the sloped corrigated asbestos roof. Well, its still asbestos, so mask will be required when drilling, but, Hills have a pivoted base bracket that will secure along the ridge-line of the corrigation.

The mast is errected with all sections recoiled back into itself. The inital base section is secured, and then a ladder placed up to the end of the first base segment (3m). We then attach the ariels, dishes, waveguides, and base stations, and the loose guy wires to the top section, and push that up. Next, attach the guys to the second top section, and push up. Repeat. Etc. Again.

When all section sare up, we attach the guys to the securing points. Rough measurement puts the width of the building at 22 metres. So from the middle to the brick wall is 11m. Lets go for 90* offsets, so 11m across. Doing pythagors, that means the level distance from the mast to the securing point is (11^2 + 11^2)^0.5 = 15.556 m. From the brick wall where the securing points are, the base of the mast is about a metre lower. So the top of this point is 2 metres higher. Again pythagorus: length of the first guy is 15.684m. At the 6 m mark, guys are 16.340m. At 9, they are 17.493 m. 12 m = 19.053 m. 15 m (very top) = 20.928 m.

Length of guy ropes
MarkGuy Length

Given we have a four way guy system, we would need 357.994 metres of guy wire, bare minimum.

Next objective: base station, another galaxy dish or two. Will a single base station at this point in "infrastructure" mode be the idea, or a separate network ESS ID completely independant? A Dual card Orinoco, or cheaper Compaq?

Update: April 3rd

Curent idea: geta cheap version 1 Apple Airport, and mod it for going up a mast and doing POE. Get an Orinoco Serial/Ethernet client adaptor, and use this and a galaxy style parabolic reflector for patching into HH.

I am testing this weekend with a cherry picker and a laptop at each end of the 2.4k link I am after. If thi is good, then we'll continue and purchase the other bits. We may even get a professional mast installed or see about going up a neighbours mast. *shrug*

Update: April 7th

Cherry Picker: we hired a cherry picker from Lees Hire on Scarbrough Beach Road. $220 or so for 24 hours. It was 12 metres tall. We tried a few antennas, and ended up with an 18 dbi conifer on the end of a 6 metre galvanised steel pole attached to the (empty) basket of the 12 metre cherry picker. We have 15 metres of LMR-400 and a 4 metre coax run of something else, which we then removed the 4 metres and dangled the guts of my deshelled airport in the air on the LMR-400 and just stumbled for it. Woot! SNR of 10 - 14 in the pack on the ground where I live!

So, back to the mast planning. Oh... did you want pictures of this event?