PHILIPS 8FZ 510

GENERAL DESCRIPTION

25 kW AM SHORT-WAVE TRANSMITTER TYPE 8FZ 510 channelized

General

This powerful short-wave (2.3-26.1 Mc/s) broadcast transmitter can be quickly adapted to changing conditions owing to the ease with which another frequency can be chosen.

The fact that the drive units are channelized makes this possible: up to three separate drive units are available, each of which can be tuned in advance to any desired frequency. A simple switch-over connects the drive unit selected to the 25 kW output stage which can then be tuned to the appropriate working frequency inside a few minutes.

Description

The transmitter comprises 6 cabinets: a power supply, a modulator, up to 3 drivers and an output stage.

The drive units each include a crystal-controlled oscillator, the crystal being enclosed in an oven to ensure the required frequency stability in all circumstances. These drive units are supplied with plug-in coils for the frequency range specified.

The output stage is continuously tunable and can be easily adjusted to the required frequency.

Only push-pull stages are used in the modulator and a specially designed negative feedback circuit helps to ensure an extremely high modulation quality.

The use of modern air-cooled transmitting tubes results in great efficiency. This and the fact that operation is simple, being restricted to a few manipulations, make the 8FZ 510 very economic to run. The little maintenance required can be effected quickly, for doors and extending panels give easy access to all components.

The transmitter is equipped with an extensive safety and protection system, including a quick-trip circuit which cuts off the high tension for very short periods in the event of faults of short duration. The staff are also protected from the dangers of HT by door switches, etc.

Mechanical design

The 6 sheet-steel cabinets form a harmonious whole. Separate parts such as the HT transformer, HT smoothing filter, modulation transformer and choke, and ventilating fans can be set up behind the transmitter in a space enclosed in dummy panels harmonizing with the transmitter proper. Installation in a separate room, e.g. a cellar, is also possible.

The transmitter is fully tropicalized and the components and tubes are conservatively rated.

The detailed manuals provided give all the information needed for installation. No special tools or highly skilled labour are required. Transmitter nameplates 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
Frequency selection	one of three spot frequencies within 4 minutes
Frequency tolerance	±20.10^-6 (2.3-4 Mc/s); ±15.10^-6 (4-26.1 Mc/s)
Power output	25 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	adjustable between +5 and 0 dBm for 100% modulation in 10 steps of 0.5 dB, ref. 1000 c/s; 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	-60 dB unweighted; reference 1000 c/s at 100% modulation
Modulation capability	100%
Power supply	3 x 380 V ±5%, 50 or 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. 50 kW at 30% modulation approx. 56 kW at 100% modulation approx. 80 kW
Power factor	approx. 0.81
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	3 pre-stages (overall) + modulator: height 212 cm (84 in.); width 204 cm (80 in.); depth 90 cm (36 in.); final stage: height 212 cm (84 in.); width 102 cm (40 in.); depth 90 cm (36 in.); power supply: height 212 cm (84 in.); width 102 cm (40 in.); depth 90 cm (36 in.)
Minimum floorspace	450 x 450 cm (15 x 15 ft)
Weight	approx. 8000 kg (17,600 lb.) unpacked

TUBE COMPLEMENT
RF stages		AF stages and modulator		Rectifiers
Number	Type	Number	Type	Number	Type
4	TBL7/8000 (6961)	4	TBL7/8000 (6961)	6	DCG5/5000GB (872A)
6	QBL5/3500 (6076)	6	QE08/200	3	DCG7/100
9	QQE06/40 (5894)	4	QE06/50 (807)
3	OA2
3	E80L (6227)
3	EF91

THIS TYPE OF TRANSMITTER IS INSTALLED IN THE FOLLOWING COUNTRIES
	ITU	Country	ITU	Country
	BDI	BURUNDI