Topband: BDR redux

[Bill Tippett <btippett@alum.mit.edu>]

> That being said, how hard would it be to find the Orion AGC parameters
that
> would cause the exact same AGC characteristics as the R4C?

W8JI wrote:
>I'm not aware of any way to do that. As far as I know it has a hard
threshold, which is probably excellent for smooth steady noise. Maybe Bill
or someone else knows how.

        The way I think of this in Orion is Threshold is the "coarse" 
adjustment
set for a particular background noise level, and RF Gain is the "fine" 
adjustment.
For signals right at the noise level, often backing down from my default
100% setting for RF Gain will find a level where a weak signal "separates"
from noise.  Certainly not a hands-off adjustment, but it seems to work in
most cases and is accessible from the front panel.  In a contest, this is
about a 1% of the time problem for the signals right at the noise floor.

        I normally adjust Threshold for whatever the general band noise is 
and
then don't touch it unless the band noise changes significantly.  As Tom said,
if you have vastly different noise levels in different directions, that can be
a problem.  I normally highlight Menu > RX > Threshold, so it takes one touch
of Menu and then a turn of the Multi knob to change it.  In general I tend to
set Threshold for my highest noise Beverage.

        I do have ~6 dB more noise in the direction of a small 
town.  Unfortunately
that is at ~70 degrees azimuth which my 50 degree phased Beverages for EU now
include.  Next year I'm going to try orienting that Beverage farther North 
so it
will not include as much noise from the town.  Of course if we get southward
skewing to 70 degrees I'm hosed anyway!  Since I've been having problems with
some neighbors' satellite TV receiver birdies recently it may be time to start
looking for a more remote QTH.  Sad to say, I believe we are becoming more and
more polluted with RFI from many sources even without BPL.

                                                        73,  Bill  W4ZV




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