I used my Orion in a CW contest (WPX) for the first time to evaluate it
in that type of environment. Most of the time was spent trying different
DSP bandwidths, different roofing filter bandwidths, different AGC
settings, the NR, etc.
Curious to see how the receiver would perform in a crowded band with a
lot of strong signals, I forced the widest roofing filter (20kHz) to be
active no matter what the DSP bandwidth was set to. I was surprised that
stations 500Hz apart were easily separated when using a DSP BW of 300Hz.
Switching to the 500Hz roofing filter seem to make no difference in that
respect. At no time did I ever hear any of the chirps and birdies that
you hear on other radios with poorer IMDDR3, even with the roofing filter
set to 20kHz. All of my listening was done with the preamp turned on.
One thing that I *did* notice when changing between a wide and narrow
roofing filter was the audio output level into the headphones. Using the
wide roofing filter made the noise and signal both increase noticeably
(although the S/N ratio of the receiver seemed to be the same), requiring
me to back off on the audio gain control a bit.
Note: For those of you that want to "force" one of the roofing filters,
the filter selection does not become active until you exit the menu *and*
rotate the VFO knob.
Of the four AGC selections, FAST and OFF did not seem useable at all
because those two positions created audio distortion unless I "rode" the
RF gain control. Curiously, unlike other radios, the S-meter still
indicates signal strength when the AGC os off. The best positions for
the AGC on CW are the MED and PROG positions. PROG works quite well on a
quiet band (like 20/15/10 meters) and MED seems better on noisier bands
(like 160/80/40 meters). To gain more insight on the Orion's AGC, I
recommend that you read the treatise about digital AGC by Doug Smith,
KF6DX. Doug is the chief design engineer of the Orion and his article
can be obtained at http://www.doug-smith.net/digitalagc.htm.
The NR worked somewhat on the lower (noisier) bands but seemed to have no
effect at all on the higher (quieter) bands. This was mainly because the
NR requires that the DSP BW be relatively wide before it begins to shine.
Neither the hardware nor the DSP noise blanker would eliminate the
"tic-tic" noise from my neighbor's electric fence unless the roofing
filter was set to 1000Hz or greater. Both NBs would take care of the
noise by forcing the 1000Hz roofing filter to be active at all DSP
bandwidths, with the hardware NB appearing to be slightly more effective
on the electric fence noise.
Serious contesters and DXers who use CW should spend a lot of time trying
different combinations of the AGC/roofing filter/DSP filter/NR/NB
selections to determine how they prefer to have those settings while in
the field of combat. They all seem to interact with each other and there
is no one optimum setting for all conditions.
Most of the time I operated I used the "search and pounce" method, using
only one VFO. Many times after working a station I had to tune just
barely out of the passband to find the next station to call. Separation
of two strong signals is no problem with the Orion, even when using the
20kHz roofing filter.
I left the CW rise/fall time at the factory default of 5mS and all
stations seemed to have no trouble copying me at 30wpm due to "soft"
keying. Even the weak, watery Europeans on 20 meters copied me with no
problem, so I'm satisfied with the Orion's keying.
No big score, enjoyed playing around on all six bands, and learned more
about the Orion.
73, de Earl, K6SE
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