K2XX wrote:
>I tried to focus on weak to moderately strong DX sigs that were
challenged by nearby strong QRM. In terms of selectivity, the two rigs
were equal. Copyability was slightly better with the MP because its
audio was more penetrating, and that was even after I decreased the bass
response of the Orion from -15 to -20 dB. I was using the 1.8 KHz IF
selectivity on the Orion with the passband tuning at about +250 Hz. The
MP was using either the two cascaded stock SSB (about 2.5 KHz) filters
or the Inrad 1.8 KHz in the high IF cascaded with the stock in the low
IF. (Frankly, SSB is not easily copyable with both 1.8 KHz Inrads
invoked in the MP.) I didn't use any of the DSP features of the MP and
the RF gain was backed off slightly. The AGC setting on the MP was
"fast" while the Orion was set at 0.65 second hang and an 8 dB decay.
Joe, here are a few tips for SSB contesting using either rig. I used
an "original" MP for about 6 years before getting my Orion.
1. Using narrow filters (crystal or DSP) in either rig, you need to
adjust carrier offsets to maximize readability. This explains your comment
"SSB is not easily copyable with both 1.8 KHz Inrads invoked in the MP."
You need to adjust your MP's Menu 8-9 offsets as follows:
http://www.va3cr.net/settings%20and%20troubleshooting/filters%20and%20menu%208-9%20settings.html
For the equivalent settings in Orion, you should set PBT = +150 to 200.
+250 in Orion is far too high for best readability IMHO. As N1EU said,
if you do this correctly, you should easily be able to copy signals with
DSP BW's to 1600 Hz or even less. I also use Ten-Tec's optional 1800
Hz roofing filter locked "on" for the entire duration of SSB contests.
2. I believe your comment "decreased the bass response of Orion" means
you set Audio RX EQ to -15 to -20. If so, that is correct, although it
does not help as much as setting PBT to +150 to 200. I don't recall
there being an equivalent setting on the MP for audio tailoring.
3. Your Orion AGC settings sound wrong to me. You probably
meant to say 80 dB/s instead of 8 dB/s, since the latter is not a
menu option. Assuming that is the case, 80 dB/s sounds OK, but Hang
should probably be 0.00 s, or 0.04 at most. Hang at 0.65 s will keep
your AGC from quickly responding to weak signals just like a Slow AGC
setting. In an SSB contest, there is just too much QRM to ever need
to set Hang to more than 0.04. Hang settings of 0.30-1.00 are more
useful when trying to copy extremely weak CW signals at the galactic
(white) noise floor.
4. You didn't mention it but Orion has a superb Hardware Noise Blanker.
When 10 meters is just opening or closing, with no strong signals present,
it audibly drops the noise floor by several dB making it possible to
hear weak signals better. The MP's NB would not do this.
As I said, I used an MP for about six years including 9 USA SSB wins
in SOSB10 in CQ WW, ARRL DX and CQ WPX (including current USA records for
all 3). The past 2 years I've used Orion for 2 USA wins in the CQ WW (no
entries in ARRL DX or CQ WPX). I feel Orion's AGC and front-end allows
me to copy more weak callers correctly the first time. Admittedly I have
not done a side-by-side comparison, but I do not have any plans to go back
to an MP. My initial comments after my first entry with Orion are below:
http://dayton.akorn.net/pipermail/3830/2003-October/082808.html
Note that the "rough audio" comment was due to me not properly setting up
the Heil HC-4 with Orion. This was the first time I used the rig on SSB.
73, Bill W4ZV
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