New Portable VHF Air Band Base Station
The DITTEL Avionik KRT2-TB2 air band portable VHF base station is the follow-on to the very successful FSG-PC series by Dittel Messtechnik. Developed by PJ Aviation in South Africa in collaboration with Walter Dittel, Germany, the goal was to produce a unit which was stronger, yet with simplified construction, easier servicing, modern design and convenient to use. Reduction in weight without compromising strength was a major goal in the development and this was achieved with optimum use of a combination of high strength corrosion resistance alloys. Accuracy of dimensions and fits is achieved through the use of CAD/CAM in a highly automated facility in Johannesburg.
The well known yellow Dittel portables of yesteryear, employed polyurethane cases which did not fair well in a tough environment and exhibited a poor RF ground plane. PJ Aviation’s TB2 housing is an all metal design, providing an almost perfect match for the flex bade antenna. The alloy used in the outer shells and face is resistant to salt water corrosion and denting. The internal framework is from CR12 steel. A high quality powder coating is applied to the shells and face plates. The light grey/black colours are standard, but users placing high volume orders may choose their own.
The handle is polished stainless steel bar, and a polished thin stainless steel cover clips over the face plate to provide a protected storage area for accessories during transport. This stores underneath during operation. Particular attention has been taken regarding the security of the battery during transport and rough use. Yet removal and replacement is an easy task.
Battery charging on a portable has to be optimum to provide the longest operating times in the field. Merely charging to 13,8v does not achieve a full charge and long battery life. The TB2 uses an automatic charger with a 2A constant current characteristic to 14,6v, equalizing the cells, and then dropping back to a 13,8v trickle. For worldwide universal use, the mains charger is rated for 100 to 240VAC, 50 or 60Hz. Mains charging status is indicated on the face plate with a bi-colour LED. To de-clutter the face plate, the mains charging socket is fitted at the bottom of the case,
External 14VDC charging sources can be connected to the current limiting external DC charging connector. The battery voltage may be read on the KRT-2 radio’s LCD.
The standard battery is a sealed 12v/7AH lead gel type, but a LiFePO4 battery with internal BMS and short circuit protection is available. This increases the operating time by 40%, ensures a minimum of 6W carrier output on battery power alone (not always possible with a lead type due to the lower voltage) and reduces the portable’s overall weight by 20%. This battery is required when the KRT-2 radio is loaded with special firmware for higher carrier power.
The loudspeaker is a waterproof mylar cone type. A dynamic microphone is provided, but a speaker-microphone may be ordered instead for man-pack operation. An extra socket can be provided for ATC recording equipment, on request. The well proven and rugged Holmco metal tubular dynamic microphone stows inside a tube through the face plate during transport. Headsets with in-line PTT switches are also available. When the headset is connected, the speaker is automatically muted.
The antenna is a sheathed steel blade type with swivel joint, allowing the TB2 portable to be used upright or propped up on its handle on a desk. External co-linear antennae and compact telescopic masts are available on request.
PJ Aviation
In the first 6 months, almost 200 portables were produced for professional and defense clients worldwide. For fixed base operations, PJ Aviation has now begun production of a 19 inch rack mount version, with transmitter output 6w to 25W, and with remote control facility.
