PHILIPS 8FZ 701

GENERAL DESCRIPTION

10 kW AM SHORT-WAVE TRANSMITTER TYPE 8FZ 701 continuous tuning

General

The type 8FZ 701 continuously tunable short-wave transmitter is a versatile and simple station for broadcasting in the 2.3-26.1 Mc/s band. Installation, operation, and maintenance can all be carried out by unskilled staff.

The transmitter is forced-air cooled and works reliably—also when continuously operated—in extremely varied climatic conditions, including tropical.

Description

The transmitter is made up of three units and a number of separate elements. The units are: the RF stages, the modulator and the power supply section. The separate elements include the mains and modulation transformers and the blowers.

The RF unit houses the driver stage, which is a self-contained but built-in unit, an intermediate stage and the output stage. The driver stage includes a crystal oscillator and a choice of up to 10 crystal-controlled frequencies is possible. Alternatively, a continuously tunable VFO can be incorporated.

The various stages are continuously tunable and the entire frequency range is divided into a number of switch-selected sub-ranges.

All tuning buttons are on the front panel, which greatly simplifies tuning. Remote control is also possible.

The circuits used in the second, i.e. the modulator unit, ensure that modulation distortion is very slight over a wide frequency spectrum.

The third unit comprises the power supply equipment for both the modulator and the actual transmitter.

Meters required for checking the working of the transmitter are built in.

Safety devices are fitted at important points as a safeguard against overloading certain components or to protect the operating and maintenance staff.

Mechanical design

The three main units are housed in individual cabinets which give the transmitter an attractive appearance when placed side by side.

The RF unit and power supply unit have a door on the front. The modulator is constructed on a slide-out panel.

As a rule the separate transformers, etc. are placed behind the transmitter, but they may also be set up elsewhere, e.g. in a basement.

Two blowers, one for the RF unit and one for the modulator, provide the necessary cooling. They too are placed behind the transmitter.

Only tropicalized parts and materials are used in this transmitter, and tubes and components are conservatively rated.

Detailed manuals contain all the instructions needed for installation, maintenance and operation.

Assembly is extremely simple and can be effected without a need for special tools or highly skilled staff.

Transmitter name-plates and instruction manuals are normally supplied in English. Other languages (e.g. Spanish) are available on request.

TECHNICAL SPECIFICATIONS
Frequency range	2.3-26.1 Mc/s, continuously tunable
Frequency selection	one of up to ten crystal-controlled frequencies
Frequency tolerance	±20.10^-6 (2.3-4 Mc/s); ±15.10^-6 (4-26.1 Mc/s)
Power output	10 kW (carrier)
Output impedance	600 ohms balanced
Standing wave ratio	max. 1.4:1
Spurious radiation	as per CCIR recommendations
AF input impedance	approx. 600 ohms balanced
AF input level	0 dBm ±2 dB, reference 1000 c/s at 100% modulation; 0 dBm = 1 mW into 600 ohms
Linear distortion	within ±1 dB from 30-10,000 c/s, reference 1000 c/s at 60% modulation
Non-linear distortion	less than 3% from 50-10,000 c/s at 90% modulation
Noise level	better than -60 dB unweighted, reference 1000 c/s at 100% modulation
Modulation capability	100%
Power supply	3 x 380 V ±5%, 50 and 60 c/s ±5%, four-wire mains; adaptation to other voltages by means of an optional separate auto-transformer
Power consumption	at 0% modulation approx. 21 kW at 30% modulation approx. 24 kW at 100% modulation approx. 30 kW
Power factor	approx. 0.82
Ambient temperature	at sea level: +10° to +45° C under tropical conditions; at 6000 ft: +10° to 35° C
Relative humidity	up to 95%
Dimensions	transmitter proper: height 212 cm (84 in.); width 202 cm (80 in.); depth 90 cm (36 in.)
Minimum floorspace	450 x 280 cm (15 x 9 ft)
Weight	approx. 2500 kg (5500 lb.) unpacked

TUBE COMPLEMENT
RF stages		AF stages and modulator		Rectifiers
Number	Type	Number	Type	Number	Type
4	QBL5/3500 (6076)	4	QBL5/3500 (6076)	3	DCG6/18 (6693)
5	QQE06/40 (5894)	8	QE06/50 (807)	8	DCG4/1000G (866A)
1	OA2
4	E80L (6227)

THIS TYPE OF TRANSMITTER IS INSTALLED IN THE FOLLOWING COUNTRIES
	ITU	Country	ITU	Country
	MDG	MADAGASCAR