TELERANA
Documentation and General Notes
INDEX
1. Antenna Theory
a. Log Periodic
b. Telerana
2. Antenna Design
a.
b.
c.
d.
e.
f.
Elements
Structure – Pole , ropes, hub
End Inserts, Bakelite strips
Tower
Rotator System
Balun
a.
b.
c.
d.
e.
Basic Frame
Tower
Elements, Trans Cable, Solders
Balun
Misc.
3. Specifications
4. Precautions and Tips
5. Possible failures and remedies
6. References, Sources
a. Books
b. Suppliers of the material
c. Useful Contacts
7. Future Scope
a. Controller
b. Suitable foundation
c. 7 MHz Elements
8. Team behind the antenna
9. Drawings
1. ANTENNA THEORY
Log Periodic Antenna
Definition:
A broadband, multi-element, unidirectional, narrow-beam antenna that has
impedance and radiation characteristics that are regularly repetitive as a
logarithmic function of the excitation frequency.
The log-periodic dipole array (LPDA) consists of a system of driven elements, but not
all elements in the system are active on a single frequency of operation. Depending
upon its design parameters, the LPDA can be operated over a range of frequencies
having a ratio of 2:1 or higher, and over this range its electrical characteristics —
gain, feed-point impedance, front-to-back ratio, etc. - will remain more or less
constant. This is not true of any Multielement Directive Array Antenna, for either the
gain factor or the front-to-back ratio, or both, deteriorate rapidly as the frequency of
operation departs from the design frequency of the array. And because the antenna
designs discussed earlier are based upon resonant elements, off-resonance operation
introduces reactance which causes the SWR in the feeder system to increase.
Figure 1
As seen in Fig.1, the log-periodic array consists of several dipole elements
which each are of different lengths and different relative spacing. A distributive type
of feeder system is used to excite the individual elements. The element lengths and
relative spacing, beginning from the feed point for the array, are seen to increase
smoothly in dimension, being greater for each element than for the previous element
in the array. It is this feature upon which the design of the LPDA is based, and which
permits changes in frequency to be made without greatly affecting the electrical
operation. With changes in operating frequency, there is a smooth transition along the
array of the elements which comprise the active region.
Even though the LPDA is simply an array of number of dipoles, more than one
elements are responsible for transmission and reception at any given frequency /
frequency band. The region, comprising of adjacent elements with lengths slightly
more or less than the resonating length for the band frequency, is said to be active
region. Before explaining the theory as to how transmission and reception takes place,
we need to turn to the basics of antenna theory.
An element is said to resonate at a particular frequency, if its length is equal to
λ/2 (two arms of length λ/4) and the element offers resistive load to the source. If the
length of the element is smaller than the resonating length at that frequency the
element acts as capacitive impedance and elements with length greater than the
resonating length act as inductive load. Thus, in case of a three element antenna array,
the longer element placed at appropriate distance (i.e. properly tuned) would cause the
effect of leading voltage and thus would act as a reflector whereas smaller element
placed at appropriate distance(once again properly tuned) would cause the effect of
lagging voltage due to inductive effect.
Now consider the LPDA. Its active region, that portion of the antenna which is
actually radiating or receiving radiation efficiently, shifts with frequency. The longest
element in LPDA is active at the lowest frequency of interest where it acts as a half
wave dipole. As the frequency shifts upward, the active region shifts forward. The
upper frequency limit of the antenna is a function of the shortest, element. Each
element is shorter than the element to its left. Ratio of each element to each adjacent
element is constant, and is given a value known as tau (τ). Another critical factor in
the design of the LPDA is the relative spacing between the elements given by the
factor sigma (σ).
Elements in LPDA are driven with a phase shift of 1800 with respect to the
earlier element by alternating the element connections as shown in Fig. 1. At a given
frequency, as the inter-element spacing ‘d’ expands , there comes a point at which the
reactice components of the current plus the 1800 phase shift caused due to alternate
feeding added to the phase delay introduced by the transmission line length ‘d’ adds
up to 3600. This is the ‘Active Region’. Thus, elements slightly longer than the
resonating length act as inductance and behave like ‘parasitic reflector’ and the
elements slightly shorter than the resonating length act as ‘parasitic director’ I since
they act as capacitive impedance. This gives rise to the directional pattern of radiation
from the longer elements to the shorter elements. The currents in the rest of the
elements are negligibly small and thus can be neglected as contributors o the radiation
field for that frequency.
V array is one of such popular designs in LPDA which effectively reduces
span of the array and also gives a good front to back gain. The Telerana begins as a
standard-design 13-element LPDA with a Tau of 0.9 and a Sigma of 0.05
Telerana
The TELERANA (Spanish for ‘Spider Web’) was first designed by George Smith,
W4AEO, and Ansyl Eckols, YV5DLT. The design first appeared in QST for July,
1981 and has been in most editions of The ARRL Antenna Book since that time (pp.
10-13 to 10-16 in the 18th Edition). A modified hybrid, consisting of the basic
Telerana with parasitic reflectors, by Markus Hansen, VE7CA, appeared on Volume 4
of The ARRL Antenna Compendium (pp. 112-117).
This is a rotatable log periodic antenna that is light weight, easy to construct and
relatively inexpensive to build. The array consists of 13 dipole elements properly
spaced and transposed along an open wire inter-element feeder having an impedance
of approximately 400 Ohm. The array is fed with a 4:1 Balun and RG8/U cable placed
inside the front arm end leading to the transmitter. The direction of gain or forward
lobe is away from the small end.
The antenna is used for the frequency range 14-30 Mhz. (Fig 2)
Fig 2
Elements
2. ANTENNA DESIGN
Most of the antenna construction and design has been taken from the antenna
handbook. The antenna contains 13 elements. Elements are chosen to be 7/22
insulated flexible stranded copper wires to keep the overall weight very low. Each
element consists of 2 parts on either side of the transmission cable. Element parts are
soldered to the transmission cable.
Transmission cable constitutes of
2 parallel running feeder cables.
Both are bare copper wires
(described as COPPERWELD
WIRE No. 14). The transmission
line is fixed tightly between the
two opposite rod ends. The two
wires of the transmission cable
run almost parallel to each other
separated periodically by the
bakelite insulators. The two
transmission cables never cross
each other. To achieve a phase difference of ½ wavelengths in consecutive elements,
alternate elements are soldered to the transmission cable on opposite sides. (See fig 3).
Fig 3
Structure
Poles, Hub, Ropes
Poles
Perhaps the most crucial part of the Telerana are the support poles. They are the
skeletal members and virtually every part of the antenna is connected to them. Vast
span of the Telerana is supported and kept taut by these poles. To ensure perfect
antenna working these must be non metallic and this fact makes it even more difficult
to find correct material for them. Further because this antenna (and so the poles) are
exposed to the weather all the time, reliability and aging resistance of the poles is very
important too.
Fiber glass (Epoxy) is the material recommended in the ARRL handbook. Fiber glass
is perfectly insulating and is very elastic too. It is able to bear high tensile and shear
loads and its resistance to weathering is very significant too. It is resistant to aging in
the Sun and is water repellent too. So Fiber Glass poles used for pole-vaulting are
used in the antenna structure. They are 15 foot long, hollow tubes of fiber glass and
are acquired from M/s Farrago Products, Meerut. (See Reference)
Hub
These poles are connected to each other to form a 90 Degree cross using a metallic
hub. This is the only metallic load bearing portion of the antenna and is the only
connection with the tower too. It has to be very strong in bending as the stretched
ropes and bent poles and kept in position by its arms. Hub is constructed out of a
metallic hollow tube and 4 other portions of smaller diameter tubes (arms) welded to
the central tube. The arms receive the poles and are provided with holes perpendicular
to their axes for making arrangements to secure the incoming poles. (See Fig 4)
Fig 4
Ropes
These are the load bearing members. They are used to bend the poles and are in
Tension always. This tension helps the antenna retain its tautness and assures that all
the elements are in the same plane. They are used as both, members to carry the
second end of the elements (One end being soldered to transmission cable) and also
the members to keep the poles in bent state. So ropes need to be stronger and weather
proof so as to withstand heavy weathering.
Generally no other ropes than Nylon ropes are water repellent. Further to avoid
withering of ropes in the Sun. they need to be UV treated. The only valid option
remains is the rope used in Parachute. These are extremely tough braided Nylon ropes
with UV treatment to prevent cracking and withering.
Actual ropes used are braided Nylon ropes obtained from local resources. (See
Reference 5.b) They are used in two types. Important load carrying ropes are slightly
thicker than the element end ropes. Ropes are tied to the poles via the Nylon Rod
Inserts described in the following section. To join the ropes and element wire ends, a
special bakelite connector is fabricated instead of an egg type insulator recommended
in the ARRL handbook. So there are very few ‘rope to rope’ or ‘rope to wire’ knot.
This ensures tautness and reliability. Ropes are tied to the inserts by passing them
through and then tying a knot to prevent back travel. (Fig 6)
Fig 6
End Inserts, Bakelite Insulators
End Inserts
Since fiber glass poles are reinforced glass epoxy poles, they might split on drilling.
Further if drilled too much at the end, stress concentration might weaken the whole
structure leading to damage. So it becomes difficult to tie the ropes to the poles. Also
the ropes carry sizeable amount of tension so require a reliable mode of securing.
Merely tying them around is not enough. This led to a concept called END INSERT.
These are simple small structures, tubular in nature, with dimensions adjusted so as to
fit exactly INSIDE the fiber glass poles. They are inserted in the poles up to 4 inches.
An across pin is inserted to ensure they don’t go in completely. These inserts are
drilled for 3-4 holes along the length with axes of the holes perpendicular to the
insert’s axis. (See Fig. 7 & Drawing)
Bakelite Strips
These are of 2 types.
1. Insulators along the transmission line.
2. Insulators / Connectors between element ends and ropes.
1. Insulators along the transmission line: They
are fit so as to secure a particular position to the
element leads on the transmission line. Elements
are spaced according to the original design in the
ARRL handbook. Bakelite strips prevent stress in
the element to be directly transferred on the
soldered joint. They also support the transmission
line as they are firmly secured to the rope parallel
to the transmission line. Bakelite is chosen as the
material for its insulating property and easy
machinability. These inserts are made in the
workshop by hack sawing from a bigger sheet
and then drilling holes. The dimensions are
specified in the specifications.(Fig 8)
Fig. 8
2. Insulators / Connectors between element ends and ropes: These are used
instead of egg insulators
as described in the
original ARRL design.
These insulators perform
no special task. They are
used only to avoid wire
rope direct knot and have
a little flexibility while
adjusting element wire
lengths. A peculiar way of passing element and nylon ropes through the drilled
holes makes them perfect for the task. (Fig 9 above)
Tower
The antenna performance can never be realized to its fullest till it is lifted in the air to
a significant ground clearance. Also since the antenna is directional, it has to be
rotated about its axis. Tower specially designed for this purpose does all these tasks
along with the traditional task of supporting the antenna.
A much customized design of the tower has been selected and used for this antenna.
Since this literature is concerned with the antenna in totality, it is vital to mention the
main design considerations made in its tower design too.
Considerations and special features
1. The mast: The mast, made up of angles, is essential to
support the two bearing plates. It has a peculiar cross
angle structure. Its height is almost up-to ¾ length of
the main tube. This ensures low bending stresses in the
tube.
2.
Legs: Legs are chosen to be slanting angles. They form
the base of the tower and total span of about 4ft by 4ft.
They are supported by two extra support angles attached
diagonally. The legs are bolted to the ground using
special axial plunger foundation bolts.
3. Bearings: These bearings are perhaps the only members
who take direct compressive load. This load comes from
self weight of the antenna and the hub. Only other
members who take direct compression are the bearings
inside the bigger gear box. Therefore the bearings used
are ‘taper roller’ bearings. These bearings are designed
to take axial load along with reducing friction while
rotating. Further because maintenance of the antenna
(and so of the tower) may not be done periodically, self
lubricated type maintenance free bearings are used.
The bearings are fitted in special bearing caps and the
caps are welded to the mast by 4 angles forming a cross.
Two such bearings are used, one at the hinge plate and the
other, about 10 ft. above, marking the end of the mast.
4. Hinge: This is the specialty of this tower. The tower
can be brought down to workable levels within a few
minutes using this hinge. The hinge actually
joins the two tower parts viz. mast and the
base. Hinges used are normal 4inch hinges (2
Pieces). Hinges are fixed the side angles and
the whole tower is arranged such that when
taken down, the mast falls exactly on the
parapet
walls.
5. Tube: This part holds the antenna. It is made up of 2
parts. L onger broader part of the tube consists of a
3inch diameter ERW (Electric Resistance Welded)
pipe, 20 ft. in length. It passes through both the
bearings and is connected to the gearbox output shaft
by a flexible coupling. The other end of the tube
receives the second part of the system which is a 2½
inch diameter ERW pipe. This pipe is about 7 ft. in
length and is used so that the hub, which carries the
antenna, can slide on it. This pipe has periodic holes
(drilled perpendicular to the pipe axis) to facilitate
fixing to the main tube and also to the hub.
6. Base frame and Misc.: To facilitate proper alignment of the gear boxes and the
motor, certain transverse base strips are welded. They are drilled very precisely to
accommodate the base foundation bolts from the rotator system. Spacers are used
to match all the heights. Utmost precision in this arrangement ensures smooth and
reliable rotation which is important.
The whole structure is first primed and then oil painted to prevent rusting and
corrosion. The motor is provided with tin sheet covering while gear boxes are also
covered with suitable arrangement.
Rotator System
Since the antenna is directional in character, it is absolutely essential that it rotates.
Further it is also essential that it rotates with:
1. Slow Speed – to avoid unnecessary loading, jerks and ensure reliability.
2. Reversal of direction – to avoid coiling of the transmission coaxial cable.
3. Fine control – to facilitate remote control.
4. Single way power transmission – to avoid unwanted rotation.
Thus the antenna rotator system is chosen to be an single phase electric motor drive. It
is used with a geared reducer system to make the speed slow and induce reliability.
Design of geared system is done according to standard mechanical engineering
practices and a double stage WORM GEAR reducer is chosen.
Salient features of such a drive:
1. Reduction Ratio: With a duble stage worm reducer, a very high reduction
ratio is achieved. Since the output RPM desired is very less (1-2 RPM),
one has to find a geared system which reduces the standard motor speed of
1440 RPM to acceptable limit. It is possible to obtain about 70 times
reduction using a worm gear. Therefore worm gear is chosen. Two stages
are used to obtain a very high reduction of (30 x 40 = 1200).
2. Single way drive: Antenna is free to rotate in the bearings and so may
rotate unwillingly due to wind pressure. There has to be a system to check
such an unwanted rotation. Worm gears being inheritedly single way
drives take care of this difficulty. A worm gear box rotates only when
input shaft is powered. Rotation of output shaft does not induce rotation of
input shaft. In fact it opposes. So Worm gear boxes ensure redundant
movement of the antenna.
3. Motor: Single phase 1440 RPM motor is used. This motor is readily
available and requires commonly available single phase 230V 50Hz.
supply. This guarantees remote operation with safety. A DC motor would
have given much higher starting torque with ease in reversal too, but cost
of a DC supply added to it the risk of using a high DC voltage in outdoors
inhibits its use. This AC motor is easily reversed by changing the capacitor
position as shown in the circuit diagram.
Figure 10
Supply to:
Common and A: One direction (Say Clockwise)
Common and B: Reverse direction (Anti-Clockwise)
4. Couplings: The system is coupled to the tube using a flexible coupling.
This coupling is the only mechanical linkage between the antenna and the
rotator system. This gives the additional advantage of isolation of various
subsystems. In case of failure of motor, antenna working is not hampered
and vice versa. Similar couplings are used to couple the motor and gear
boxes with each other. Smaller reduction ratio gear box is coupled first to
the motor. Then it is coupled to the bigger gear box with higher reduction
ratio. This gear box is chosen such that it has its output shaft vertical.
Balun
A balun is a device performs two important tasks:
1) Balanced to unbalanced transformation
2) Impedance transformation
The term BALUN is in fact derived by combining BALanced and UNbalanced. A
balun is a special type of transformer that joins a balanced line (The currents through
the two terminals are equal in magnitude and opposite in phase) to an unbalanced line
(one side connected to electrical ground and the other conducts all the current).
Balun may also provide impedance transformation in addition to this conversion
from balanced to unbalanced. LPDA has a characteristic impedance of 200 to 300
ohms, whereas the coaxial cable used (RG 8) has a characteristic impedance of 50 to
75 ohms. This impedance transformation is essential for perfect matching and
maximum power transfer. This can also be achieved by using a balun constructed
from transmission line. However an important parameter in the design is based on
length of the transmission line as a function of frequency. Thus, LPDA being a broadband antenna cannot use such a balun. Thus a Balun transformer has to be used. As
the impedance conversion ratio needed in case of LPDA is a round 4:1, the working
and construction of a 4:1 balun transformer is explained here.
The figure 11 shows winding of a conductor on a toroid. The toroidal core is
available in various sizes and specifications. Number of turns has to be altered
according to the table given below.
Toroid
T80-2
T106-2
T130-2
T157-2
T200-2
T200A-2
T400-2
Number Of Turns
25
16
18
16
17
13
14
Power Rating
60W
100W
150W
250W
400W
400W
1000W
The number of turns is not absolutely critical, as the functioning of a transformer
as regards the voltage / current / impedance transformation is simply based on the
ratio of the number of turns. However, in practical applications, we also have to take
into account the fact that the inductance of these windings comes in parallel with the
antenna and thus, we have to make sure that he reactance is high enough to be ignored
as compared to the antenna impedance (which is resistive) even at the lowest
frequency. The resistance of the windings should also be negligible. Most
constructions use #14, #12, #10 or #8 enameled wire for windings.
Following diagram (Figure 11) shows construction sketch of the balun used in
Telerana. It consists of 7 turns of enameled Copper wire (gauge 16). To keep the
number of turns adjustable according to requirements, the construction is altered.
Finally the balun has 7 turns as shown in the diagram.
Figure 11
The Balun is connected to the antenna as shown in the figures below. The leads A, a,
B and b to be matched with the construction diagram shown in Figure 12.
Figure 12
3. SPECIFICATIONS
a. Basic frame
i. Main Poles
1. Pole Material: Fiber Glass EPOXY
2. Pole Length: 15 ft. continuous. (POLE-VAULTING POLES)
3. Pole Diameter: Outer diameter – 35mm, Inner diameter – 23 mm
4. Pole Electrical conductivity – TOTALLY INSULATING,
5. Pole Dielectric Strength - ~10KV per mm
ii. Spreader Pole
1. Pole Material: Fiber Glass EPOXY
2. Pole Length: 15 ft. continuous
3. Pole Diameter: Outer diameter – 19mm, Inner diameter – 11 mm
4. Pole Electrical conductivity – TOTALLY INSULATING
5. Pole Dielectric Strength - ~10KV per mm
iii. End Inserts
1. Material: Nylon (Readymade rods)
2. Diameter: 1Inch (23mm)
3. Length: 1 ft.
4. Part inside the pole: about 50%
iv. Ropes
1. Thicker ropes for all basic frame connections
2. Thinner ropes for internal connections
3. Every cross between rope and wire etc. tied with Fishing Cord.
v. Hub
1. Arm length: 30 inch
2. Central pipe: 4 inch diameter (Part of the bigger main tube)
3. No. of arms: 4
4. Primed and oil painted
b.
i.
ii.
iii.
iv.
v.
vi.
vii.
viii.
Tower
Angle size: 40 x 40 x 5 (L angle)
Thickness: 5 mm
Material: MS (Primed and oil painted)
Span at foundation: 4 ft x 4 ft
Tube 1: 20 ft long x 4 inch diameter
Tube 2: 7 ft long x 4 inch diameter
Tube 3: (Bamboo used) – 12 ft length.
Axial holes: Perpendicular holes on the smaller tube at 6 inches interval.
c. Elements, Trans Cable, Solders
i. Elements
1. Type of wire: 7/22 Stranded flexible insulated Copper wire
2. Maker: FINOLEX
3. Length: Cumulative about 330ft. (100 meters)
4. Color: Blue (Any)
ii. Transmission Cable
1. Type of wire: No. 14 Copper-Weld bare Copper wire.
2. Maker: Local
3. Length: Cumulative about 65.6ft. (20 meters)
iii. Soldering
1. Peculiar way of soldering as discussed above
2. Solder metal used to be without any flux
3. Joints polished with sand paper before soldering
d.
i.
ii.
iii.
iv.
Balun
Type: Ferrite core, Toroidal shaped core
No. of turns: 7 (double coil)
Type of wire: Enameled Gauge 10 copper wire
Impedance ratio: 4:1
e.
i.
ii.
iii.
iv.
v.
Misc.
Ropes to be tied to upper part of the mast while tilting
Bricks or certain arrangement to receive the mast on the parapet wall
Hose clamps: 2 inch diameter x 4nos. at the pole-hub joint
Pin inserted in the inserts be of M4 maximum diameter
Hub to tube and tube to tube joints are M6, 5inch bolts with washers & nuts
4. PRECAUTIONS AND TIPS
1. Tower to be tilted only after tying 4 way ropes at the top end of the mast and
pulling them with substantial manpower. All the 6 bolts are first removed. Then
the tower may be pushed to begin the downward motion.
2. Gear boxes to be filled with specified oil. (Once in a year)
3. Electric motor to be tested atleast once a month to avoid rusting and jamming.
4. Tension ropes tied above and below the antenna may be adjusted periodically
to maintain balanced posture of the antenna.
5. Hose clamps at the hub joint to be tightened every time the antenna is brought
down. This ensures that poles take load without splitting.
6. Coiling of transmission cable to be avoided with equal rotational movements.
7. Whole antenna can be removed from the base frame by removing inserts at the
four ends. Thus in case of a pole breakage or a rope breakage first all the
inserts to be taken out.
5. POSSIBLE FAILURES AND REMEDIES
1. Flipping: (Not expected in near future) This was the first failure to occur due to
high winds. Thus a bamboo is fitted above the antenna hub and 4 cords are tied
from the top of the bamboo to the 4 rod ends. This avoids flipping.
2. Cord breakage: (Expected in 2-3 years) Since the cords used are not UV treated,
they are expected to give away any time after 2 years. In such case, ALL THE
CORDS taking similar tension must be changed (Broken / Intact).
3. Pole cracks: (Not in the next 10 years) Remove all the inserts and then change
ALL THE POLES. Spreader may not be changed unless absolutely essential.
4. Insert comes out or sinks in: (2 years) Change the particular insert possibly with a
UV treated insert. All the inserts may not be changed.
5. Element solder gives away (Not expected): Try not to cut the element length.
Instead some skilled soldering may be employed to ensure intact element length.
6. Coupling at the tube-gearbox joint breaks: (Anytime in the next 2 years) This
happens as the coupling is the only load bearing member in case of wind load
rotating the antenna. So when it breaks, the antenna rotates unbounded and coiling
of the coaxial cable may take place.
Coupling change is very easy. Specified coupling is readily available. It is to
be bored to required diameter and then fitted on the Gear box. Tower has to be
tilted (Only about 15 Degrees) to fit the coupling.
7. Rotation is not smooth: (Not expected in the next 2 years) Lubricate all the
bearings. Also lubricate / service the gear boxes and the motor. Tube may be
checked for excessive bending (Not expected at all).
8. Antenna performance deteriorated: (Time can not be predicted) Change the Balun.
Also look for possible breakage / shorting of the transmission cable. Secure the
connections of the transmission cable with the Balun.
1. Books
6. REFERENCES, SOURCES
a. ARRL Antenna Handbook
b. QST magazine articles
c. Websites of W4RNL (Cebik W. B.) , VE7CA (Markus Hansen)
2. Suppliers of the material
a. Poles
FARRAGO PRODUCTS
Reinforced Plastics & Allied Fields
77-Nauchandi Ground (Oppo. Gandhi Murti)
Meerut City,
Pin: 250002 U. P. India.
Tel: 2700002/3 Fax: 0121-2700178; e mail: farrago@hclinfinet.com
Web Site: http://www.indiamart.com/farrago Mobile: 0 9412202824.
b. Ropes, Nylon fishing cord
E. T. KAPUSWALA
363, Ravivar Peth, Pune: 411 002
Tel.: 2447 6493
(This supplier is NOT RECOMMENDED HENCEFORTH as the
ropes supplied were NOT UV treated.)
c. End Inserts
M/S POPATLAL AND SONS
363, Ravivar Peth,
Next to E. T. Kapuswala,
Pune: 411 002
d. Hub and tower
M/S METAL CRAFT
Shukravar Peth, Shivaji Road, Pune
Tel.: 24471798, 94225 31798
e. Motor
M/S MOTHER (MICA ELECTRICALS)
Budhwar Chowk,
Pune: 411 002
f. Gear boxes
GREAVES COTTON LIMITED
Akurdi, Pune.
(Mr. Sai S., BGII, P. T. U.)
g. Element and feeder cables
SINGH ELECTRICALS
Next to Pasodya Vithoba temple,
Guruvar Peth, Pune: 411002
h. General Hardwares (Local traders in Bohri Aali, Shukrawar Peth)
3. Useful Contacts
MR. KELKAR (VU2EN)
“Bintang”, Next to Kamala Nehru Park,
Off Prabhat Road, Pune : 411 004
Telephone: +91 (20) 25475545
MR. MARKUS HANSEN (VE7CA)
674, St. Ives Cres.
North Vancouver BC,
V7N 2X3, Canada
WEB SITE: www.qsl.net/ve7ca
Email: ve7ca@rac.ca
7. FUTURE SCOPE
1. Controller: The antenna rotates in both directions by changing motor supply. This
rotation is according to direction requirement. To achieve accuracy and ease in
operation a controller may be designed which will:
o Show current position of the antenna on a dial
o Stop the rotation when desired change of direction takes place
o Constantly give feedback whether supplied current is causing rotation or
not.
2. Foundation: The antenna legs are bolted using special foundation bolts to the
terrace floor. This may be further reinforced with string foundation using cement
concrete and bricks. PWD department of the college may help in designing and
actuating the procedure.
3. Bonus 40 m coverage: As described by VE7CA on the website, modified Telerana
has a dipole of 40 m and 30 m used instead of tension cords above the antenna to
work as tension carrying elements. This gives additional advantage of these two
bands. Thus this is a complex but useful alteration in the future.
8. TEAM BEHIND TELERANA
This project has been primarily carried out by the final year students of the college.
Members:
1. Prakash H. K. (hkprakash7@yahoo.com) (Secretary) (VU2HKP) E&TC
2. Parag Deotare (p_deotare@yahoo.com) (VU2PBF) Electrical
3. Hemant Chavan (hsc_1982@yahoo.com) (VU2HHH) E&TC
4. Madhura Sane (madhura9@yahoo.com) E&TC
5. Rujuta Kulkarni (krujuta@yahoo.co.in) E&TC
6. Aditi Vadnagare (aditivadnagare@rediffmail.com) E&TC
7. Neeti Gore (neetigore@hotmail.com) E&TC
8. Sushrut Pavanaskar (psushrut@sancharnet.in) Mechanical SW
9. Shantanu Jathar (sjathar@gmx.net) Mechanical
10. Aniket Rane (dangerous_aniket@hotmail.com) Instrumentation
(This documentation is compiled by Sushrut with helping hands from Madhura and Prakash.)
© COEP Amateur Radio Club, 2004.