Bill, Barry and Martin, thanks for your comments and input.
First, let me comment on diversity reception. I have only tried it on
40M where I have both an EDZ and a vertical. That seemed like a good a
combination of the best of both worlds. In general, I wasn't impressed
one way or the other. I didn't seem to get any advantage when both
antennas were active. I thought it was primarily meant to improve
readability when there was QSB. However, I really only looked at it for
a short while and didn't get back to it. I hadn't even considered
combining an all band flat top or similar with a beam antenna.
Intuitively, I didn't expect anything to be gained. I'll take another look.
Obviously from my subject line, I was surprised at what I was hearing.
In the past when I compared the two rigs on CW, the Orion seemed to have
better selectivity, although the difference was pretty small. In the CQ
WW I worked 80M CW with the Orion, and was really surprised at how free
from pops and squeals it was even when there was very close in QRM.
However, I didn't do any A/B testing at the time.
Barry and Bill, I hadn't tried narrower bandwidths with the Orion
because I expected the SSB to be unintelligible. I remember Bill's
original post to the MP reflector with his carrier offset
recommendations. They made a major difference in received signal
intelligibility. I have even carried it one step further when I hear
sigs with muddy audio, usually DX; I adjust the offset to whatever
setting yields maximum intelligibility. I have often commented that the
control should be on the front panel. Similarly, the effect on SSB
transmitted audio is also quite dramatic and easily seen on a scope. I
just went and checked, and I was using -100 Hz offset on RX USB this
weekend. I had played with the PBT on the Orion a little before
settling at +250, but maybe I should have done a little more experimenting.
Frankly, I thought I was using an 85 dB decay on the Orion AGC. As I
was writing my original post, I went and checked to be sure and was
surprised to see it at 8 dB. I have been fooling with PSK31 a lot
lately and probably changed it while in that mode. (BTW, I'm using the
N4PY software to set the AGC and that's why I can get an 8 dB decay
setting.)
I have very little need for the NB at this QTH. Bill, I went back and
read your original post. Frankly, I'm a little surprised that the NB
works on white noise, and I´ll check that out. However, every time I
have compared the two rigs on weak signal reception, mostly CW, I find
little, if any, difference. It may be that my requirements are less
demanding than yours. I am only a casual contester. On the other
hand, I really go out of my way to pull weak sigs out of the mud even
with routine QSOs. I will continue making comparisons.
I should also comment, that I have found that invoking the NR often
increases the noise. Another correspondent suggested turning down the
RF gain when that happens. He commented that the apparent noise level
seems to increase, but there is in fact an improvement in S/N ratio.
Generally, I run the RF gain just above the threshold where noise is
audible. This weekend 15M was very quiet and I was at about 88 setting.
Again, I appreciate all your inputs. I'll continue experimenting and
get back to you.
73, Joe
Bill Tippett wrote:
>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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>
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