Having been checking the S-Meter for my prefered software solutions (SDR) I thought it might be a good time to also (re)check the S-Meter in my ICOM IC-7610. The setup is the same as for the previous two checks. Below is the result of my checks for my IC-7610. A quick graph of how well my ICOM IC-7610 S-Meter is tracking using the proverbial 6dB steps (6dB/S-Unit).
Setup:
- Signal generator: XG3
- Level: -34.8dBm @ 13.8V
- Att: HP-355C & HP-355D (38dB for approx. -73dBm level)
- Frequency: 14.175MHz
Result:
CLICK on the GRAPH for a better view.
The graph shows a pretty linear S-Meter for the IC-7610 up to S5 however, it is at 3dB steps. It is not following the 6dB/S-Value IRAU Standard. The above graph has been produce with the PreAmp off.
It is interesting though, that the Attenuator (ATT) values are in 6 dB (6/12/18 dB) steps, which would indicate that ICOM is familiar with the 6 dB scaling value for S-Meters.
Not only would it be nice to have a 6dB per S-Point scale it would also be nice to have S-Value compensation when using the additional Pre-amplifiers.
Maybe a firmware/software update? It is afterall a Software Defined Radio. I would hesitate a guess that it would not be that difficult to implement this kind of behaviour. It has been shown that Amatuer coders can make this possible, even accommodating different receiver gain settings, i.e. compensating for attenuation or amplification.
Here is a note from ICOM's S-Meter blurb for the IC-R8600!
Absolute Value of RSSI (Received Signal Strength Indicator)
The IC-R8600 shows S-meter, dBμ, dBμ (emf) and dBm meter types in the RSSI. The dBμ, dBμ (emf) and dBm meter has a high ±3dB accuracy* (between 0.5–1100MHz) that can be used for measuring signal strength level.
Why can't we have 6dB S-meter steps and have the same display functionality as the IC-R8600 in our IC-7610, why ICOM?
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