Deflection Of The S Meter Needle; Noise Level - Kenwood TS-990S In-Depth Manual

03 RECEPTION

Deflection of the S Meter Needle

The IARU (International Amateur Radio Union) standard scale requires ‑73 dBm as the S meter level to point S9. However,
concerning the S meter needle deflection, on all our products, the S meter level is ‑81 dBm to point S9 in the 14 MHz band while
a pre‑amplifier is on. The TS‑990S also provides S meter needle deflection familiar to operators using a conventional model.
Turning off the pre‑amplifiers lowers the gain and the S meter needle deflection. The gain changes by a pre‑amplifier by
approximately 12 dB in the amateur bands up to the 21 MHz band and by approximately 20 dB in higher bands.
The "S Meter Levels (Reference)" table shows the indicated levels of the S meter. (The S meter level is adjusted to point
S1, S9, or S9+60 in the 14/50 MHz bands.)
In FM mode, you can select the same configuration (High) as that has been configured for conventional models, or a
lower value enabling to lower the S meter sensitivity, through Menu 0‑08 "FM Mode S‑meter Sensitivity".
S Meter
S1 (3 dots)
S3 (11 dots)
S5 (19 dots)
S7 (27 dots)
S9 (35 dots)
S9+20 (48 dots)
S9+40 (59 dots)
S9+60 (70 dots)
Fig. 21 S Meter Readout (Analog)

Noise Level

With a pre‑amplifier active, the sensitivity increases by the gain and internal noise, and the S meter needle is
easily deflected and the noise level rises. The sensitivity decreases with the pre‑amplifier inactive; however, the IP
characteristics improve, noise level lowers, and the S meter needle cannot be deflected. In addition, the IF gain is
corrected so that the gain, sensitivity, deflection of the S meter needle, noise level, and other factors appropriately
change.
With a pre‑amplifier active in a band below 21.5 MHz, the noise level will not increase. However, with a pre‑amplifier
active in a band above 21.5 MHz, the noise level increase relatively.
14
Table 5 S Meter Levels (Reference)
0.03 to 21.5
21.5 to 60 MHz
MHz
‑107.0 dBm ‑114.0 dBm
‑100.5 dBm ‑107.5 dBm
‑94.0 dBm ‑101.0 dBm
‑87.5 dBm ‑94.5 dBm
‑81.0 dBm ‑88.0 dBm
‑61.0 dBm ‑68.0 dBm
‑41.0 dBm ‑48.0 dBm
‑21.0 dBm ‑28.0 dBm
FM (High)
‑117.0 dBm ‑117.0 dBm
‑114.4 dBm ‑112.8 dBm
‑111.8 dBm ‑108.5 dBm
‑109.2 dBm ‑104.3 dBm
‑106.6 dBm ‑100.0 dBm
‑102.4 dBm
‑98.9 dBm
‑95.0 dBm
Fig. 22 S Meter Readout (Digital)
FM (Low)
‑93.2 dBm
‑87.4 dBm
‑81.0 dBm