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AMATEUR RADIO BY GARRY CRATT, VK2YBX Kenwood's TS-450S HF transceiver Recently, we were given the opportunity to review Kenwood's latest HF transceiver offering, the TS-450S. Despite a front panel that boasts some 50 controls, it proved to be easy to drive. Once the TS-450S had been delivered to our lab, it quickly became obvious that significant advances had been made in HF transceiver design since last we peered into such a unit. This transceiver, whilst capable of delivering 100 watts, is remarkably compact in size, measuring 280 x 340 x 107mm and weighing in at just 6.3kg. As Kenwood themselves state, this transceiver is an ideal candidate for DX-peditions where weight is at a premium. However, considering that the receiver draws 2A at 13.8V, provision of a power supply of adequate endurance and capacity is quite im- Below: this photo shows just some of the accessories available for the Kenwood TS-450S. The PS-53 power supply is capable of delivering 22.5A, a necessity in order to obtain the full 100-watt output of the TS-450S. Also available is the TS-450SAT, a model with an inbuilt automatic antenna tuner. 38 SILICON CHIP portant and should be taken into account by those contemplating mobile or portable operations. It took just 15 minutes with the instruction manual for us to work out the basic controls, thus allowing us to fire up the receiver and listen to activity on the various bands. As we soon discovered, one of its most useful features is the ability of the synthesiser to operate in 1Hz steps! This function is controlled from the front panel and allows either 1Hz or 10Hz increments to be selected for SSE operation. For AM or FM operation, the synthesiser step is set to 100Hz increments, giving l0kHz of coverage per revolution of the tuning knob on SSE and 50kHz for AM and FM operation. Combined with the added features of IF SHIFT and an adjustable audio NOTCH (400-2600Hz), the small synthesiser steps make it easy to tune two adjacent channel SSE signals and resolve either one. In fact, we also tried this feature on the time standard signals which appear at 10.00MHz on AM, with similar results. One other sophisticated, yet essential feature, considering the congestion of the HF bands, is the ability of the user to select different bandwidth IF filters for various modes of operation. For SSE, there is a choice of 6kHz, 2.4kHz and 500Hz, the last two being plug-in options. For CW and AM operation, the filter choices are 12kHz, 6kHz, 2.4kHz and 500Hz. The receiver uses triple conversion, having intermediate frequencies at 8.83MHz and 455kHz, and the filters at both these frequencies can be switched to select the most suitable IF bandwidth. If the 2.4kHz position is selected for both 8.83MHz and 455kHz, the combined effect of both filters results in a bandwidth of 2.2kHz. Of course, the receiver section also caters for some of the more exotic transmission modes, such as FSK and packet(AFSK). In fact, there is a dedicated socket on the rear panel of the transceiver for direct connection of either an RTTY terminal or TNC. Both FSK shift and receive tone are user selectable via the user accessible "function selection programming menu", as are 42 other receive and transmit parameters, including CW pitch, RIT increments, frequency steps for both VFOs, numeric keypad disable, data transfer between radios, The complex front panel of the Kenwood TS-450S makes it quite daunting to look at but the unit turned out to be quite straightforward to drive. It offers state of the art technology. memory channel write protect, memory split frequency operation and transmit inhibit. There is also a socket, located on the side of the transceiver, for direct connection to the optional "IF-232C" RS -232 interface, which allows 25 functions to be controlled via a personal computer. The SCAN function can be used to either scan the entire 500kHz to 30MHz band, or to scan the 100 memory channels. By selecting the FINE mode, scanning is incremented in lOHz steps. We found the receiver section easy to operate, although the main tuning knob lacked the customary dimple for locating the tuning digit. Nevertheless, with adjustable dial drag'and direct frequency entry via the front panel keyboard, we were soon accustomed to rapidly changing from one HF band to another. The UP and DOWN tuning controls can be programmed to increment the tuning range in either 1MHz or 500kHz steps in conjunction with the "lMHz" key, or in the normal tuning mode, they step between the nine amateur HF bands: 160m, 80m, 40m, 30m, 20m, 17m, 15m, 12m and 10m. There are also two different noise blankers fitted to the transceiver, one for short duration pulse noise and the other for "woodpecker" type radar noise interference. Our test unit also had the optional voice module (VS-2) fitted. When the "voice" button is depressed, a synthesised voice indicates the frequency to which the receiver is tuned. There is also provision to connect Kenwood's "Digital Signal Processor" DSP-100, an external signal processor for both transmit and receive use. This makes use of several multi pole active filters and 16-bit D/ A and AID converters which give waveshape restoration, thereby providing superior performance. We plan to review this unit in a subsequent issue. To evaluate the transmitter, we ran the usual bench tests for transmitter harmonics, output power, FM deviation, frequency accuracy and spurious radiation. Transmitter harmonics were well suppressed, almost to the level required by the new DOTAC commercial specification, ECR 235. However, conducted spurious signals were quite noticeable at 100MHz with harmonics up to 500MHz sometimes approaching -60dBm (quite a significant level). These changed as the various bands were selected, leading us to believe that they are related to the microprocessor control circuits. Frequency accuracy was well within the specified limits. At 29MHz, we recorded a frequency error of 136Hz, better than twice the accuracy quoted, and the FM deviation limiting worked well to keep the maximum deviation below ±5kHz. Current drain at maximum power reached 21A, something to be considered when selecting a suitable power supply. As 25% of the rear panel of the transceiver is dedicated to the PA heatsink, maintaining an adequate temperature for the transmitter should present no problem, provided suffi- cient clearance is allowed for air circulation. Overall, we were very impressed with the TS-450S. The transceiver offers state of the art technology in a compact size and at an affordable price. The 95-page instruction manual covered all aspects of the operation and contained easy-to-read circuit and block diagrams of the transceiver. We did lift the lid to see if the unit was field serviceable and found that all components, and often their functions, were silk-screened onto the PC boards, indicating a thorough ap proach to the transceiver's design. Some components are surface mounted which would require specialised repair equipment. However, considering the service facilities offered by Kenwood, that aspect should be well covered. There is a comprehensive range of accessories for the TS-450S, including External Antenna Tuner (AT-300), Data Transfer Cable (E30-3047-05), VS2 Voice Synthesiser, Digital Signal Processor (DSP-100), IF 232C RS-232 Interface, TU-8 Tone Unit, AT-450 Automatic Antenna Tuner, SP-23 External Speaker and a range of eight IF filters . There is also range of communications headphones, RF filters and various hand and desk microphones. Recommended retail price of the Kenwoo'd TS-450S is $2204. For further information, contact Kenwood Electronics Australia Pty Ltd, 8 Figtree Drive, Australia Centre, Homebush, NSW 2140. Footnote: all transmitter tests were carried out under the terms and conditions of the author's DOTAC experimental license. SC AUGUST 1992 39