[TenTec] Orion Threshold and RF Gain Settings

[Barry N1EU]

Lee Crocker <w9oy at yahoo.com> wrote:
>So what's the use of the AGC control then?  

It was the original implementation of the firmware, before the RF Gain control was reprogrammed to add control of AGC Threshold.  The only thing you can't control with the RF Gain knob is the minimum limit of threshold (effective value of AGC Threshold when RF Gain is turned to max), and that's why you need to have the AGC Threshold menu setting quite low (<1uV).

All of the issues you bring up are dealt with with the RF Gain control.  Go ahead and theorize and complicate.  I just turn up "RF Gain" slightly above the level that I start to hear band noise.  This takes into account receiver gain, antenna gain, band condx, phase of the moon, whatever . . .

73,
Barry N1EU





Why not
>just eliminate the control and set the value as a
>constant in firmware.  My guess there are some small
>but real advantages in dynamic range and MDS when
>setting up the stage gains for a given system when
>analyzed from the antenna to the speaker, and it is my
>guess that these parameters change according to what
>antenna is chosen etc.  For example how you set up the
>stage gains may be quite different between a beverage
>out on the back 40, and a vertical sitting next to a
>noisey power poll in the front yard.  It is likely
>there are different settings for each of the filter
>combinations you choose, and there are likely
>different settings of best performance for each
>antenna/filter combination you choose.  Exactly how to
>tease these out in something other than a subjective
>way I have yet to figure out.  
>
>If you did actually develope a methodology to quantify
>best performance, you could then store those valuse in
>a database, and call them up as you switch in various
>antennas filters and receiving conditions etc.  When
>is a 2db difference useful?  When the signal your
>trying to recieve is 229, or when your trying to copy
>"dingbat" in the miles per watt contest.     
>
>73  W9OY
>
>
>        
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