Tait T500 series
The Tait T500 series radios are a 'compact' mobile radio series, available in a number of configurations. Some are useful for 4m/6m, some 2m band candidates (T530/535), and some are 70cms capable (T555?). There are also a number of other versions, some of which are trunked, and some which are 200MHz targeted - which are unable to cover 2m/70cms - avoid these! The radios themselves are constructed from a two plastic 'lids, which is coated with conductive paint on the inside for shielding purposes. Along with the radio PCB these form the chassis and give the radio its rigidity. They are fitted with BNC connectors for antenna circuits, and have hardwired microphones, which are connected at the front of the radio, entering the set just under the front panel.
Most are two channel, although Tait do sell a 99-channel conversion module, which allows frequencies to be programmed into the radios using EPROMS. My 100-channel conversion design uses a similar principle.
No crystals involved - fully synthesised. Stornos, although synthesised, require a pair of new crystals and can only tune within 2MHz (approx) of this, whereas the Taits are tunable over a large frequency area.
No component changes necessary - NONE. Not even capacitors in the receive coils, as these radios are spec'ed for use in a frequency range which covers the amateur bands.
Aesthetically pleasing - sort of! Most of the major controls - vol, squelch, call (toneburst) are already fitted to the front panel. All that is needed to give a 100-channel set is to cut a small opening for thumbswitches.
Compact - These radios are considerably smaller and lighter than Stornos, or other PMR models popular conversion radios. Unfortunately this is both a blessing and a curse - it can make fitting additional boards etc, quite awkward.
Very stable - for example, it is hard to tune up the transmitter in such a manner that it is unstable. This is the opposite of such radios as the Burndept Dymar, which by comparison, is very hard to tune stably!
Clearly marked - The circuit board/s of the Tait are extremely well silk printed, and service adjustment points, such as the Deviation Adjust Potentiometer is well marked. This avoids the need to pore over a layout diagram to find those elusive components!
Lots of documentation - Tait have just released all the service manuals and other documents, which are very helpful for info about how to tune up the radios etc.. See here
Can be hard to find these days - not really a fault of the model itself!
Vehicle mounting kits are very rare - the mounting kit consists of a metal tray and two clips which attach to the sides of the radio, and it then slides into the tray. A special key is required in order to remove the radio from the case.
They get hot - As much of the radio is plastic, apart from the transmitter heatsink area, the radio can become very hot if used for long periods on transmit. This is simply a design 'feature' - and usually doesn't cause damage unless excessive. If you are using them for a high duty-cycle application, simply reduce the power output.