[Premium-Rx] Help With Conversion Calculation

[Ben Wallace]

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