[Kenwood] TS-830s IF Amp Alignment Question

[Clif Holland]

That would be fine except for one thing. All of those charts are for the USA 
usage of uV and dBM conversions. The Japanese sytem starts at 0dB =  .5uV, 
not 1 uV as you are assuming.

Clif Holland KA5IPF
www.avvid.com




----- Original Message ----- 
From: "Steve Harrisonusa" <k0xp at dandy.net>
To: <kenwood at mailman.qth.net>
Sent: Thursday, July 31, 2008 2:30 PM
Subject: Re: [Kenwood] TS-830s IF Amp Alignment Question


> >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
>
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