Hi Eric --
Well, I'm going to stick my neck out on the reflector and describe what I
have been using for SSB contests. Probably some other
people can point out how my settings can be improved.
a) In the "Filters" menu, turn off auto-select and force the use of the 1.8 kHz
filter. (Don't forget to revert back to auto for
CW - hi!)
b) Set bandwidth to ~2000 Hz, according to degree of band crowding and your
taste. I've run the bandwidth all the way down to 1700
Hz in horrible crowding. On a less congested band like 10m, I'll open it up to
2100 or 2200.
c) Set passband tuning +150-200 Hz. This shift compensates for the narrow
filter choice to improve intelligibility.
d) AGC: use "prog" setting with parameters like these:
AGC Hang: I tend to keep this short, <0.20 seconds, in a contest on a
crowded band, where I want to be able to at least hear
the presence of a weak caller in the gaps between loud signals overlapping my
listening frequency. 0.12 seems OK, and I've even
used 0.00. This is certainly not a good setting for conversational QSOs.
AGC Decay: I run pretty fast decay, again to allow the AGC to drop down
quickly to catch a weak stations. ~50 dB/s seems OK.
This is definitely NOT a conversational setting!
AGC threshhold: I start with this value at its maximum (191.48 microvolt),
and reduce it until I start to hear band noise just
come up on an empty frequency. Tune outside of the band if no empty frequency
can be found. On a very crowded band like 40m, I
will use an even larger setting. There is no value, and some harm, in setting
this parameter too low on a band full of loud
signals. Set it just low enough to reliably copy the weakest signal detectable
among the QRM or QRN. This value is the most
variable -- it depends on conditions, local noise, and your antenna in use on
the band.
e) NR and NB: off unless absolutely necessary. Why do more processing on the
signal than one needs?
f) AN: I leave this off unless I encounter a situation where a notch filter is
needed. Same idea: do the least amount of
processing on the signal for the conditions.
I'm looking forward to hearing others weigh in...
73,
-- Eric K3NA
-----Original Message-----
From: Eric Rosenberg [mailto:wd3q@starpower.net]
Sent: 2004 November 3 15:54
To: eric@k3na.org
Subject: RE: [Orion] ORION PERFORMANCE
Eric --
Can you be more specific about your changes?
As I said in my email, I lose track of my expectations... and then get
messed up trying to figure out if the radio sounds as good as it should!
Parameters like NR (which was great on the Omni-6+) just didn't seem
right to me; I haven't gotten the hang of the AGC, nor do I really
understand the HW NB and the H vs L in re: PBT.
I suspect I'll eventually get there...
Eric
---- Original message ----
>Date: Wed, 03 Nov 2004 14:56:23 -0500
>From: Eric Scace K3NA <eric@k3na.org>
>Subject: RE: [Orion] ORION PERFORMANCE
>To: Bill Tippett <btippett@alum.mit.edu>, orion@contesting.com, Oms
PY5EG <py5eg@iesa.com.br>
>
>Hello Oms --
>
> I share Bill W4ZV's opinion that your troubles with the Orion were
probably due to sub-optimal receiver settings.
>
> At the multi-op station where I was working this past weekend, I
relieved an operator and found his Orion sounded very noisy and
>trashy. It was quickly apparent that:
> -- the hardware noise blanker had been left on unnecessarily
> -- the AGC threshold setting was far too low for the conditions on
the band
> -- the filters, bandwidth setting, and passband tuning was not being
exploited for best results.
>
> Some quick adjustments later, and signal readability was greatly
improved.
>
> One might say: "The use of this radio is not intuitive, so an
operator unacquainted with it can not use it effectively." But,
>more precisely, the Orion gives the operator a number of additional
controls which the operator needs to understand. But, once one
>has a good mental picture of the receiver and what each control does,
it's easy.
>
>-- Eric K3NA
>
>
>
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