[Orion] More to Sherwood's Orion test

Bill Tippett btippett at alum.mit.edu
Mon Mar 29 09:56:16 EST 2004


W0YG wrote:
 >OK rob indicates the s-meter is dead on at S9=50mv.  With the preamp on, S9
is 12 mv.

         I'm wondering if Rob may have interchanged his Preamp On result 
and then
interpolated in the wrong direction for Preamp Off based on his 13 dB preamp
gain measurement?  I say this because I recently built Elecraft's XG1 Receiver
Test Oscillator which generates precision (+/- 1 dB typical) 1 uV and 50 uV
signals at 7040 kHz.  I checked my Orion and 50 uV from the XG1 yielded ~S9
with Preamp On, but ~S7 with Preamp Off (which would imply about 200 uV would
be required for S9 with Preamp Off).  My results are also closer to ARRL's on
page 26 of their ETR.  They measured 33.5 uV required for S9 with Preamp On
and 135 uV with Preamp Off.

         Bottom line is I believe Orion is correctly calibrated for S9 = 50 uV
with Preamp On, not Preamp Off.
                                         73,  Bill  W4ZV





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