The Cellphone industry continues to boom in India, and cellphone towers are
all over the place. This is not surprising since the mobile phone has become
popular with every body. Even the poorest seem to carry a mobile phone since
it is quite inexpensive and useful. The rich like to flaunt their expensive
handsets even though they can barely manage to input text properly for
sending sms messages!
Almost all cellphone towers are made out of angle iron. The same is the case
with vhf/uhf commercial towers and microwave links. I have never seen an
aluminium tower around here. The stronger towers are made out of angle iron
sections bolted/welded together. The vhf/uhf towers are made with thin ms
iron rods welded together with the typical zig-zag sections. There are two
types available in 10 ft. sections - the light variety which looks very
flimsy and cannot support an HF antenna, and the heavier variety which just
MIGHT support an HF antenna. The trouble is nobody has heard of a large
rotatable HF beam! The towers are meant for fixed commercial antennas.
I visited a welding workshop which has done some work for cellphone
companies, and the owner told me that he would be able to fabricate one for
me if I can give him the drawing and details. Now, as Jim said, though the
basic design of the crank up tower is quite straightforward, it is the
details which have to be properly worked out... as to how the sections will
travel within the lower section, and the cable etc.
Hopefully, I will be able to manage something or the other soon. I have made
a note of the points suggested by you, Bill W2AY, especially regarding the
insulators in the guy wires and the downward force of the antenna.
Regarding the amateur radio scene in VU land, it is correct that there are a
very few operational hams especially in the region where I live. In my city,
which is a very important capital city of about a million people, I am the
only ham operational on HF! The number of active hams north of New Delhi can
be counted on the fingers of one hand. Most VU hams on HF have dipoles as
antennas. Only a handful have beams installed. Another popular choice is to
homebrew a bamboo quad - which is messy but works well.
I earlier had a 40'foot homebrewed telescopic iron mast with inverted vees
for 80, 40 and 20. On top of the mast was an X-300 dual bander. The mast was
stuck into a drain pipe and guyed all around with GI wire. It was incredibly
heavy, and impossible to work upon for maintenance etc. While carrying out
repairs, even four men holding it could not handle it properly, and it came
crashing down on one side breaking the fibre glass tubing of the X-300.
Fortunately, no other damage was done. Thereafter, I vowed that I would only
use a light aluminium pole even for a dipole. Better stil, I would invest in
a better crank up style tower with which one can easily carry out repair
work on the antennas!
Sorry for the long over! I thought I would give you guys the complete
picture.
Amit VU2 ZZA.
P.S.- Even with the dipole I managed to make many contacts with stateside
and VE stations. The old antenna can be seen here
http://www.flickr.com/photos/8808920@N02/1392088948/
On Tue, Jun 9, 2009 at 11:37 PM, amit singh <amlogin@gmail.com> wrote:
>
>
> ---------- Forwarded message ----------
> From: amit singh <amlogin@gmail.com>
> Date: Tue, Jun 9, 2009 at 4:11 PM
> Subject: Re: [TowerTalk] Design/Drawing for Crank up tower
> To: Bill Fikis <w2ay@atmc.net>
>
>
> Thanks a lot for the response.
>
> Firstly, I would preferably have it on the roof. Secondly, the height
> should preferably by at least 35-40 feet. The roof height is about 24 feet
> from the ground. We live in a low rise area, and the houses around are
> maximum three storeys high. This will give an overall height of about 55-60
> feet. Thirdly, guy lines can be put since there is space around the house to
> fix them. The roof is a plain flat roof - 60' x 20' with no structures. One
> possibility is to fix the tower at the first floor level and then fix it by
> the side of the house.
>
> 73
> Amit.
>
>
> On Tue, Jun 9, 2009 at 12:24 AM, Bill Fikis <w2ay@atmc.net> wrote:
>
>> amit singh ....
>>
>> Are you planning to install tower on top of roof ??
>>
>> How tall do you want the tower ??
>>
>> Do you want guy lines for the tower ??
>>
>> Is there room beside the building for the tower ??
>>
>>
>> .............Bill / w2ay
>>
>>
>> ******************************************************************************
>> Subject: [TowerTalk] Design/Drawing for Crank up tower
>>
>>
>>
>> Hello,
>>>
>>> I write this from Chandigarh, India. I have been following the posts on
>>> this
>>> group, and learning a lot in the process.
>>>
>>> I have a new Australian made HB-35-C tri-band yagi (Boom length 4.00
>>> metres,
>>> Max element length 10.6 mts. Weight 22 kgs, Wind Loading 1300n) and a
>>> Yaesu
>>> G-1000DXA rotator. Now all I need is a suitable tower to put this on! I
>>> have
>>> a two-storeyed flat roofed house.
>>>
>>> My problem is that I do not have a suitable design or drawing in order to
>>> get a 3-section crank up tower fabricated. Such towers are not
>>> commercially
>>> available, locally, and the only option I have is to get one fabricated
>>> for
>>> myself with a simple achievable design. I wonder if anybody could help me
>>> in
>>> this respect.
>>>
>>> 73's,
>>> Amit
>>> Vu2ZZA.
>>>
>>>
>>
>
>
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