Rx Dynamic Range - Kenwood TS-480 User Manual

How well does it actually perform? Fig. 8 is a graph illustrating the dynamic range characteristics
when changing the separation of two interfering signals. For the sake of reference, results for the
TS-480 are plotted against those obtained using other compact mobile transceivers (on the
market) under the same conditions.
Fig. 8: RX dynamic range
Looking at Fig. 8, results higher up the graph indicate wider dynamic range.
When the RX frequency is 14.100MHz, and for example there is simultaneous interference from
two signals at 14.150MHz and 14.200MHz, with the nonlinearity of the RX section, spurious
signals are generated at 14.100MHz and 14.250MHZ, enabling reception. Since the frequency
separation at this point is 14.200MHz -14.150MHz = 50kHz, the +50.0KHz point on the horizontal
axis of Fig. 8 corresponds to these conditions. Under these conditions, if there were interfering
signals that were faintly picked up by the other transceivers in this comparison, the strength of
those interfering signals would have to rise by 10~15dB for the TS-480 to begin suffering the same
effects.
When there is interference in close proximity to the RX frequency, there is no difference between
these models, with one notable exception. In this area we are approaching the bandwidth of the
roofing filter, so to put it another way, the fact that we can observe a difference between the
transceivers at the +50kHz point – where the interference is sufficiently eliminated by the roofing
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