[Premium-Rx] Help With Conversion Calculation

[Ben Wallace]

Hi Chuck,

Ahhh yes.........Thanks for the info.  BTW....I called Dr. Bailey and we 
worked through the same example and came up with a similar answer.

I thank you very much for the refresher !!!

Ben





At 08:55 PM 12/3/02 -0800, Charles Hutton wrote:
>Ben:
>
>To make the conversion from power (dBm) to volts, the first thing to do is
>specify an impedance (resistance). Let's assume 50 Ohms. Then, it's a
>question of Ohm's Law in the correct form. Remembering that power = voltage
>* current, and that current = voltage / resistance, we combine them and
>power = voltage * voltage / resistance.
>
>Re-arranging to solve for voltage:   V = square root of (resistance * power)
>
>Your -100 dBm signal is equal to 1E-13 Watts. V therefore should be
>approximately 2.3E-6 Volts or 2.3 microvolts.
>
>
>
>I'm tired (spent the day on the roof working on the chimney), it's late and
>I hope I have not mis-typed or mis-thought anything.
>
>
>Chuck
>
>
>-----Original Message-----
>From: premium-rx-admin at ml.skirrow.org
>[mailto:premium-rx-admin at ml.skirrow.org]On Behalf Of Ben Wallace
>Sent: Tuesday, December 03, 2002 8:31 PM
>To: premium-rx at ml.skirrow.org
>Subject: [Premium-Rx] Help With Conversion Calculation
>
>
>To the group:
>
>Perhaps I am getting old or drinking to much beer......but I need some help
>with a calculation.
>
>The de facto standard for S-Meter readings is 50 micro-volts at the antenna
>input to register an S-9 reading on the S-Meter.
>
>Now the issue........On my HF-1000A, I do not have an S-Meter.  The
>HF-1000A has a meter that reads the input signal directly in dBm.
>
>For the life of me, I cannot come up with a conversion of dBm to
>microvolts.  For example:  Is there a way to convert an input signal of
>-100 dBm to a specific micro-volt level?  Perhaps there is an easy formula
>-- I certainly can't remember.  Maybe I need a refresher course from Dr.
>Bailey?
>
>Can anyone help out?
>
>Thanks -- Ben
>WB8HUR San Diego
>
>
>
>
>
>
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