[Kenwood] TS-830s IF Amp Alignment Question

[Steve Harrisonusa]

>I don't know where your correction factor came by but I stand by my notes.
>
>According to you the 830 was adjusted to an S-9 reading of 100uv. I don't
>think so.

Try this:
http://www.giangrandi.ch/electronics/anttool/decibel.html

... or this one:
http://www.wirelessconnections.net/calcs/dbm_conversion.asp

... or here:
http://www.microvolt.com/table.html

The Kenwood chart is just plain wrong. That was obvious when I first tried
setting my HP8640 signal generator using the volts scale and then realized
the power on the meter scale, for the uV that I wanted, wasn't what the
Kenwood manual said it should be.

Or, you can calculate it out the long way:

(by the way, that uV level is PEAK, not RMS; so to convert to average
power, you have to divide by 1.4 (or multiply by 0.714) to get RMS volts;
if I recall correctly, it's mentioned on an earlier page as being the peak
voltage)

Take 100 uV:

100uv/1.4 = 71.4 uV RMS

P = (E^2)/R; here, we're using the antenna impedance so R = 50 ohms

P = ((71.4 * 10^-6 volts)^2)/50
P = 1.02*10^-10 watts
dBW (note WATTS) = 10*log ( 1.02^10^-10)
dBW = -99.9

To convert to dBm, we simply add 30 and get -69.9 dBm.

So, 100 uVpk = -69.9 dBm.

Steve, K0XP