84 Dodge (Commer) PB 15cwt (1979) - Television Detector Van
Commer/Dodge FC/PA/PB/Spacevan (1960-82) Engine 1724cc S4 OHV
Registration Number CNJ 423 T
COMMER SET
www.flickr.com/photos/45676495@N05/sets/72157623652553073...
This van is a Televison Detector Van.
The Commer FC which was introduced in 1960 with many body styles, including a 1500 cc van. After engine and interior upgrades it was renamed the PB in 1967 and the SpaceVan in 1974. It was also sold as a Dodge and Fargo
The 1500cc engine was replaced by the 1725cc Rootes group engine mated to a four speed transmission.
One of the largest fleet users were the GPO.
Reportedly, one condition of the government bailout of Chrysler's British operations in 1976 was a commitment to upgrade the Spacevan, which was praised for its brakes, cornering, and price, but criticized for its power, comforts, and top speed. A revised Spacevan was thus introduced in 1977, using the same mechanics but with numerous cosmetic changes, conveniences, and a new interior. The last Spacevan was built in 1983.
UHF TELEVISION DETECTOR VAN
The equipment is installed in this modified 2500 Series Commer genral service vehicle. Eleven of these were made bringing the compliment of detection vehicles to two for each Telecom Region
A dummy roof houses the aerial movement mechanism. To prevent water entering the dummy roof and effecting the mechanism, the slot necessary to allow fore and aft movement of the front aerial is closed by a heavy duty zip fastened neoprene cover. Two sliders are used one mouted on the front of the aerial the other on the rear. The cover is thus opened in front of the aerial and closed behind it, as the aerial moves. A purpose built console in the body of the vehicle provides the operating position. Extra seats are provided for passengers during demonstrations.
The inside amd the roof of the vehicle is lined with washable plastic to reduce condensation. Hot air from an additional heater is ducted to the side windows to prevent misting and to the dummy roof to prevent seizure which would occur if moisture formed through condensation were allowed to freeze in low tempratures. The vehicle is fitted with Automatic transmission.in order to give smooth take off and slow speeds during detection runs.
Aerial Movement
Two separate movements are required. When the vehicle is not on a detection run the aerials are parked in line along the centre of the roof. Prior to operation it is therefore necessary to rotate them to face either the near or offside of the vehicle. Normally detection is arranged to take on the nearside, but in one way streets it may prove necessary to work both sides. The rotation of the aerials is is carried out by two cam-and-microswitch controlled D.C. shunt wound motors via worm and wheel gears to ensure that the aerials are locked in position when the power is disconnected from the motors.
The second movement is a linnear movement of the front aerial which is necessary to obtain the constant spacing of 6u between the two aerials. The front aerial is mounted on a light trolley which moves on wheels on two Z section rails. The trolley is fastened to an endless toothed belt driven by a third DC. shunt wound motor
CONTROL CIRCUITS
The positioning of the front aerial is controlled by a DC servo system. The UHF tuner shaft is coupled directly to one poteniometer and via a shaped cam to second potentiometer, which provides a correction voltage to convert from the straight-line frequency law of the tuner capacitor to the straight-line wavelength law required for the linear movement of the aerial. A third potentiometer is coupledf to the main motor gear-box to provide an error voltage. The three voltages are combined in a differential amplifier with a reference voltage from a Zener diode. The differential output is fed via two Schmitt-trigger circuits, which are included to prevent hunting, to switch a high power transistor bridge. This controls the power fed to the DC motor, to drive the aerial.
OPERATORS CONTROLS AND DISPLAY
The operators controls are mounted on a display panel on a console. To connect power to the detector, the vehicle ignition must be swithed on and the aerial position swith must be at PARK. In this position the main on off switch in the ON position connects power to the equipment. When the switch is set to OFF,power is not disconnected from the servo ststem until the aerials return to the parked position. In case an emergency such as fire, an EMERGENCY OFF position on the switch is used to disconnect all of the power from the equipment. Pilot lamps and an aerial position indicator are provided to let the operator see at a glance the position of the aerials
The panoramic receiver has three controls, frequency setting with associated digital logging displa, gain and sweep width. Brilliance focus and beam shift controls are provided for the cathode ray tubes, and an aerial control switch is fitted to select the main or either of the auxilary sensing aerials.
POWER
Power is provided by two heavy duty 6 volt batteriesin series. The batteries also provide for the normal electrical system of the vehicle and are charged by the vehicle alternator. A 230 volt 50 Hz supply obtained from the solid state invertor is used to power the panoramic receiver and the power unit for the cathode ray tube displays. Low voltage supplies for the transistor circuits are obtained from the display power pack.
CONCLUSION
A new system of Television detection has been designed, and a working prototype produced by the Post Office Regulatory Division. The production models are being manufactured by a contractor . The equipment is of a modular construction to facilitatefault finding and reduce out of service time by the replacement of faulty modules by spares. It is expected the new transistor receivers will have lower fault liability than the old thermionic v\lve receivers.
The new detection equipment enables an accurate location of the VHF and UHF telvision receivers to be made in the presence of reflections, and sensitivity allows for the low levels of radiation from modern transistor tuners.
Shot at Tatton Park, Manchester, Classic Car Show 18:08:2012 REF 88-84.
84 Dodge (Commer) PB 15cwt (1979) - Television Detector Van
Commer/Dodge FC/PA/PB/Spacevan (1960-82) Engine 1724cc S4 OHV
Registration Number CNJ 423 T
COMMER SET
www.flickr.com/photos/45676495@N05/sets/72157623652553073...
This van is a Televison Detector Van.
The Commer FC which was introduced in 1960 with many body styles, including a 1500 cc van. After engine and interior upgrades it was renamed the PB in 1967 and the SpaceVan in 1974. It was also sold as a Dodge and Fargo
The 1500cc engine was replaced by the 1725cc Rootes group engine mated to a four speed transmission.
One of the largest fleet users were the GPO.
Reportedly, one condition of the government bailout of Chrysler's British operations in 1976 was a commitment to upgrade the Spacevan, which was praised for its brakes, cornering, and price, but criticized for its power, comforts, and top speed. A revised Spacevan was thus introduced in 1977, using the same mechanics but with numerous cosmetic changes, conveniences, and a new interior. The last Spacevan was built in 1983.
UHF TELEVISION DETECTOR VAN
The equipment is installed in this modified 2500 Series Commer genral service vehicle. Eleven of these were made bringing the compliment of detection vehicles to two for each Telecom Region
A dummy roof houses the aerial movement mechanism. To prevent water entering the dummy roof and effecting the mechanism, the slot necessary to allow fore and aft movement of the front aerial is closed by a heavy duty zip fastened neoprene cover. Two sliders are used one mouted on the front of the aerial the other on the rear. The cover is thus opened in front of the aerial and closed behind it, as the aerial moves. A purpose built console in the body of the vehicle provides the operating position. Extra seats are provided for passengers during demonstrations.
The inside amd the roof of the vehicle is lined with washable plastic to reduce condensation. Hot air from an additional heater is ducted to the side windows to prevent misting and to the dummy roof to prevent seizure which would occur if moisture formed through condensation were allowed to freeze in low tempratures. The vehicle is fitted with Automatic transmission.in order to give smooth take off and slow speeds during detection runs.
Aerial Movement
Two separate movements are required. When the vehicle is not on a detection run the aerials are parked in line along the centre of the roof. Prior to operation it is therefore necessary to rotate them to face either the near or offside of the vehicle. Normally detection is arranged to take on the nearside, but in one way streets it may prove necessary to work both sides. The rotation of the aerials is is carried out by two cam-and-microswitch controlled D.C. shunt wound motors via worm and wheel gears to ensure that the aerials are locked in position when the power is disconnected from the motors.
The second movement is a linnear movement of the front aerial which is necessary to obtain the constant spacing of 6u between the two aerials. The front aerial is mounted on a light trolley which moves on wheels on two Z section rails. The trolley is fastened to an endless toothed belt driven by a third DC. shunt wound motor
CONTROL CIRCUITS
The positioning of the front aerial is controlled by a DC servo system. The UHF tuner shaft is coupled directly to one poteniometer and via a shaped cam to second potentiometer, which provides a correction voltage to convert from the straight-line frequency law of the tuner capacitor to the straight-line wavelength law required for the linear movement of the aerial. A third potentiometer is coupledf to the main motor gear-box to provide an error voltage. The three voltages are combined in a differential amplifier with a reference voltage from a Zener diode. The differential output is fed via two Schmitt-trigger circuits, which are included to prevent hunting, to switch a high power transistor bridge. This controls the power fed to the DC motor, to drive the aerial.
OPERATORS CONTROLS AND DISPLAY
The operators controls are mounted on a display panel on a console. To connect power to the detector, the vehicle ignition must be swithed on and the aerial position swith must be at PARK. In this position the main on off switch in the ON position connects power to the equipment. When the switch is set to OFF,power is not disconnected from the servo ststem until the aerials return to the parked position. In case an emergency such as fire, an EMERGENCY OFF position on the switch is used to disconnect all of the power from the equipment. Pilot lamps and an aerial position indicator are provided to let the operator see at a glance the position of the aerials
The panoramic receiver has three controls, frequency setting with associated digital logging displa, gain and sweep width. Brilliance focus and beam shift controls are provided for the cathode ray tubes, and an aerial control switch is fitted to select the main or either of the auxilary sensing aerials.
POWER
Power is provided by two heavy duty 6 volt batteriesin series. The batteries also provide for the normal electrical system of the vehicle and are charged by the vehicle alternator. A 230 volt 50 Hz supply obtained from the solid state invertor is used to power the panoramic receiver and the power unit for the cathode ray tube displays. Low voltage supplies for the transistor circuits are obtained from the display power pack.
CONCLUSION
A new system of Television detection has been designed, and a working prototype produced by the Post Office Regulatory Division. The production models are being manufactured by a contractor . The equipment is of a modular construction to facilitatefault finding and reduce out of service time by the replacement of faulty modules by spares. It is expected the new transistor receivers will have lower fault liability than the old thermionic v\lve receivers.
The new detection equipment enables an accurate location of the VHF and UHF telvision receivers to be made in the presence of reflections, and sensitivity allows for the low levels of radiation from modern transistor tuners.
Shot at Tatton Park, Manchester, Classic Car Show 18:08:2012 REF 88-84.