Procom PMC 1250 User Manual download pdf

PMC 1250

Phasing-Clamp for Creating a Certain Radiation Pattern

using Two Antennas

DESCRIPTION

The PMC 1250 can be used to create a certain desired radiation pattern

in the horizontal plane using two vertically polarised antennas mounted

side-by-side in a certain, prescribed distance, and feeding them both in

the correct amplitude and phase relationship. The PMC 1250 is mainly

designed for the 144 - 175 MHz band.

The PMC 1250 is equipped with two vertical 38 mm mast tube mounting

studs for the two antennas. One of the tubes is welded permanently to

one end of the supporting boom, and the other is able to slide along the

boom where it can be fastened at an arbitrary distance. The position of

the main clamp for the supporting mast can also be adjusted, and it

should always be positioned halfway between the two antennas.

Mostly, the antennas are fed with currents of the same amplitude, and

only the phase relationship and the distance between the antennas are

varied to produce the desired coverage. The phase relationship is

changed by introducing a delay line in one branch of the feeding cable

system.

The figure below shows representative horizontal patterns for various

values of distance D and phase delay Pd. Obviously, given a particular

antenna site and a certain geographical area to be covered, a system

like this offers a large degree of design-freedom to choose the best

characteristic possible.

Please note that the PMC 1250 should always be mounted at the top of

the supporting mast. If the PMC 1250 is sidemounted, the radiation

pattern will be very difficult to predict.

Procom offers the service of designing and quoting systems like this

especially according to the requirements of our customers.

SURVEY OF RADIATION PATTERNS (Relative field strength)

ORDERING DESIGNATIONS

TYPE PRODUCT NO.

PMC 1250 100000039

SPECIFICATIONS

FUNCTION PHASING-CLAMP FOR CREATING

A DESIRED COVERAGE

FREQUENCY 66 - 88 MHz: 1/16 λ < D < 1/4 λ

144 - 175 MHz: 1/8 λ < D < 1/2 λ

DISTANCE

BETWEEN ANTENNAS

(Variation range)

0.23 - 1.20 m

DIAMETER OF

MOUNTING STUDS

Ø 38 mm

WIND SURFACE 0.10 m²

WIND LOAD 127 N @ 160 km/h

MATERIALS Boom: Hot dipped galvanized steel

Fittings: Stainless steel

TOTAL HEIGHT Approx. 1.28 m

WEIGHT Approx. 8.0 kg

MOUNTING On 38 - 65 mm outer diameter mast tube

Antennas should be mounted symmetrically in relation to the mast.

PROCOM A/S reserve the right to amend specifications

without prior notice.

06/12/11

PMC 1250 1

Summary of Contents

Page 1 - PMC 1250

PMC 1250Phasing-Clamp for Creating a Certain Radiation Patternusing Two AntennasDESCRIPTIONThe PMC 1250 can be used to create a certain desired radiat

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Procom PMC 1250 User Manual

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