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AMATEUR RADIO BY GARRY CRATT, VK2YBX Review: Kenwood’s TS50S HF amateur band transceiver Claimed to be the world’s smallest HF amateur band tran­sceiver, the Kenwood TS-50S was released early in 1993 & has enjoyed a good reputation in amateur circles ever since. Despite its small size (179 x 60 x 233mm), the unit offers a full 100 watts of RF output power in the FM, SSB and CW modes, and a respectable 25 watts in the AM mode. The transmitter covers 160 metres through to 10 metres and the receiver offers general coverage from 500kHz to 30MHz. Like other VHF Kenwood transceivers, the TS-50S uses a microphone equipped with four user programmable function keys, allowing control of up to 26 transceiver functions. The The Kenwood TS-50S has many functions which are control­lable by the four programmable buttons on the microphone. Note the large liquid crystal display & the highlighted scanning mode. 84  Silicon Chip status of these functions is shown on the large liquid crystal display on the front panel of the transceiver. First used in the TS-950SDX HF transceiver, Kenwood has also incorporated their computer menu system into the TS-50S, to allow the user to configure 39 operating parameters, including operating frequency, RF output power, AGC mode, IF filter select, CW offset, RF meter sensitivity, sub-audible tones, five separate scan parameters, receiver incremental tuning, microphone gain, repeater tone frequency select, and many others. The receiver is also equipped with Kenwood’s exclusive “AIP” system (Advanced Intercept Point) which improves the re­ceiver’s dynamic range to a maximum of 105dB. When used in conjunc­tion with the inbuilt 20dB attenuator, this allows the user to overcome levels of high interference and strong adjacent signals. There is also a very effective IF SHIFT control, which allows the user to shift the IF passband by 1.5kHz or so, without changing the receiver frequency. Using this control, it is possible to completely eliminate adjacent frequency interference, in the majority of situations. Programmable memories The transceiver has 100 user pro- This is what the TS-50S transceiver looks like with the lid removed. There are no user serviceable parts inside! grammable memories, for independent storage of transmit and receive parameters, such as frequency, mode, and IF filter settings. The “Memory Shift” function facilitates the transfer of data to either of the two inbuilt VFOs. For CW enthusiasts, the transceiver has a “CW Reverse” function, which effectively switches from the upper sideband default position to the lower sideband position, thereby removing any adjacent channel interference heard with the transceiver in the default setting. The CW receive pitch can also be selected from 400 to 1000Hz in 50 Hz steps, without affecting the transmit sidetone. There is also an option­ al 500Hz IF filter – the YK-107C available for narrow-band CW operation. The rear panel of the transceiver supports a 3.5mm mono phono socket to allow connection of a CW key or electronic keyer. The more exotic data modes of HF operation are also sup­ported and virtually any TNC can be connected via the microphone socket. As the transceiver displays only the carrier frequency if either sideband operation is selected, it is necessary for the operator to add the modulating frequency to the displayed frequency in order to accurately calculate the actual operating frequency. Thus, to select an RTTY “mark” frequency of 14.080, the operator must tune to 14,082.125kHz on the transceiver in the LSB mode; ie, 14,082.125kHz - 2.125kHz = 14.080 MHz. The transceiver tuning can be incremented in 5Hz steps, so quite accurate results can be achieved. As there are two inbuilt VFOs, split frequency and cross band operation is also possible with the TS-50S. In fact, split frequency “channels” can also be memorised in any of the 100 memory channels. The transceiver is supplied with quite heavy-duty DC power leads, capable of carrying the 20.5 amps of current required at full RF output power. In the receive mode, the maximum current required is 1.45 amps. As this is not an insignificant figure, there is a power feature called “APO” (automatic power off), which switches the transceiver off, if none of 20 odd major controls are operated for a 180-minute period. Although this function can be de-programmed by the user, it should go a long way towards eliminating the possibility of a flat battery. Optional accessories The TS-50S has a large range of optional accessories, in­ cluding two automatic antenna tuners, (AT-300 for fixed opera­tions, AT-50 for mobile use), a 5-band helical antenna (MA-5), the SO-2 temperature compensated crystal oscillator, a range of desk and mobile microphones, various extended DC and antenna tuner cables, mobile speakers, a bumper mount for the MA-5 anten­na, and the YK-107C CW filter. Priced at $1884 RRP, the TS-50S may not suit every budget but the small size, features and ease of operation make it the ultimate choice for many mobile operators, as proven by the many units already in operation in SC Australia. June 1994  85