[TenTec] Orion Receiver Hints in High Static Conditions

Bill Tippett btippett at alum.mit.edu
Mon Aug 15 12:14:54 EDT 2005


WT6G wrote:
 >AGC: OFF       Yes, OFF.  You don't need AGC if the radio is
                 configured for a high noise environment.  You
                 may want AGC on FAST if there is a tremendous
                 difference in surviving signal strength.

         Len there is no way to truly turn Orion's
AGC off.  If you set AGC "off", look at MENU>RX
you will see the following which are fixed and
cannot be changed:

Hang            00.00s
Decay   1000 dB/s
Threshold       00.37 uV

AGC Prog actually allows you to increase
Decay a little higher to 2000 dB/s for
high QRN situations.

         Your recommendations are good and very
consistent with what we've all learned using
pre-DSP analog rigs under high QRN conditions:

AGC Off
AF Gain High
RF Gain Low (adjust up for comfortable AF output)

         For weak-signal reception in galactic (white)
noise, Orion's settings are different than for
impulse-type QRN (i.e. lightning).  Under these
noise-floor conditions, I use Decay 5 dB/s and Hang
0.30-1.00s as Sinisa YT1NT recommends at the bottom
of page 4 of his paper here:

http://www.geocities.com/va3ttn/UsingOrionRX.pdf

Of course 1.372 has made adjustment of Threshold
much simpler since Sinisa's March 2004 paper.

                                         73,  Bill  W4ZV




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