Kenwood TS-480 manual RX sensitivity

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filter – reflects a difference in the manufacturers’ approach to design from the antenna to the 1st mixer.

It is not just the mixer that determines the characteristics of the front end: all of the components between the antenna terminal and the mixer can have an impact.

Despite the compact design of the TS-480 Series, its RX BPF divides up the 500kHz~60MHz range into 10 bandwidths. Since several coils are employed in this BPF circuit, small coils have to be used in a compact transceiver. When discussing front end linearity, attention focuses on semiconductors such as the PIN diode for switching bands, but in fact the coils used in this BPF can be “nonlinear” parts, depending on operating conditions. Differences in their characteristics become more noticeable the smaller they are. In the early stages of developing the TS-480, we looked at the mutual modulation characteristics of a number of coils, picking only those that demonstrated the best performance.

With this compact transceiver it was not possible to use a passive tuner equivalent to what is found in top-end models, but our emphasis on HF performance was such that we selected components whose advantage cannot even be appreciated from a circuit diagram.

Fig. 9 is a graph demonstrating RX sensitivity. Needless to say, for HF, especially in the low bands, there is more importance attached to multi-signal characteristics than to sensitivity, but obtaining a sufficient level of sensitivity can be vital during mobile operations when one cannot expect much in the way of antenna gain.

As with previous models, sensitivity is set to switch at 21.5MHz with the pre-amp on. However, there is a difference: previously the pre-amp itself was switched, but in the case of the TS-480 this is managed by switching the pre-amp’s NFB gain.

Fig. 9: RX sensitivity

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Contents Page TS-480HX TS-480SAT Determination to create a unique transceiver Design ObjectivesBack to basics The appeal of HF lies in DX’ing Focus on basic performance Standalone control panel200W challenge Adding appeal to fixed station operations Overview of the TS-480 SeriesTS-480 concept began with development of the TS-570? Development Objectives for the TS-480 SeriesAchieving 200W output in a compact transceiver Focusing on HF Circuitry TX circuits 200W final sectionTX IMD output 200W SPS separate power sources TS-480HX only SPS schematic diagram100W final section Failsafe device some TS-480HX versions onlyAntenna tuner TS-480SAT 200W final section FM modulation block diagram FM circuitRX circuitry Front end RX 1st mixerRX dynamic range RX sensitivity Jumpers for joy Circuitry after the roofing filter Comparison of optional CW filters 500HzOption installation unit Auxiliary Features Features useful for 50MHz operationsFeatures useful for mobile operations Full compatibility with digital modes data modesNew 5MHz band DSP circuit Features of the Built-in DSPIdeal for mobile operations DNL Noise reduction Demonstrates how ignition noise is reduced by the DNLNR OFF Beat cancel BC OFFRX DSP filters Switching Width During CW operations RX equalizer & TX equalizer CW auto tuneTips TS-480 menusDSP Useful if you want to go on to tune FSK APO Functions that can be assigned to PF keys Assigned Use Split Making menus easier to use Menu switching Quick menuStructural Features Internal structure of the main unitCooling diagram CoolingUpper side Temperature rise around final transistors Page Design concept Constant recording function New Option Voice Guide & Storage Unit VGS-1Message recording/playback function Reset Configuration mode for TX output, etcMenu settings Split mode Voice GuideOther features VFO mode, direct frequency entryMemory channel Variable Voice Guide speedKNS added Main functionsButton layout & basic operation Changing memory and registered details CW keyingCompatibility with KNS Kenwood Network Command System Reading and writing filesSetting up KNS on the Arcp side Accidental continuous TXPage Using a broadband router Checking LAN settings New Option ARHP-10 Amateur Radio Host Program FreewareAdjust PC volume User setupPage Troubleshooting Network & Operations Problem SolutionCannot get KNS to work Sound Problem Solution Connect a microphone to the computer and bring up TS-480 In-Depth Manual