[Boatanchors] 75A-4 Sensitivity

[Glen Zook]

The specification is 100 microvolts through an attenuator which actually applies 50 microvolts to the receiver.  If you are using a signal generator with a true 50 ohm output then the actual signal applied should be 50 microvolts.

Most of the "olde tyme" signal generators (i.e. Measurements Model 80) signal generators did not have a fixed 50 ohm output and therefore required usually a 6 dB attenuator when aligning receivers with a specific input impedance.  Therefore, Collins specified an attenuator to "match" the output of the signal generator with the input impedance of the receiver.  "Modern" signal generators have the proper impedance and therefore the Collins attenuator circuit is not needed.

Glen, K9STH

Website:  http://k9sth.com


--- On Fri, 10/16/09, Richard W. Solomon <w1ksz at earthlink.net> wrote:

Am I reading this right ??? The spec for S-9 on the meter is 100 uV ??