Lee, the configuration I described as my preferable configuration is exactly
what Bill, W4ZV told us to do. (That's why I said do as Bill says, not as
he does. Bill doesn't work much SSB). I still operate too much SSB to
eliminate the 1.8 kHz filter. Sometimes here on our tiny little EU 40m
band, I just lock the roofing filter in at 1.8.
I will have to pass on your question regarding degrading using the 250 Hz
filter. I only remember seeing actual numbers for the 500 Hz filter and
then reading several comments about the 250 Hz filter's performance.
I would not be afraid of taking a scapal to the Orion but I would have to be
convinced it would really buy me a lot better noticable performance.
One critique I've had on the engineering experts for 20 years is that they
have always pushed the envelop on RX performance, trying to squeeze out ever
last fraction of a dB, and we all know the more the better (well, sometimes
the less the better), but NOBODY has ever defined "Good Enough".
And, I guess "Good Enough" is a moving target. So it will need defining and
qualifying!
If I do any physical mods to the Orion, I won't be on the bleeding edge.
I'll wait 6 months.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com]On Behalf Of Lee A Crocker
Sent: Thursday, July 15, 2004 5:01 PM
To: tentec@contesting.com
Subject: [TenTec] Redesigning the filter section of the Orion IF
Rick
Your post was enlightening, and thank you to the
others that responded I have 2 questions based on
your analysis. By how much is the performance
degraded in the case of the 250hz filter using the
stock configuration? What are the figures for the
600hz cascaded with the 250hz? I have read that the
cascaded filters degrade performance but I have never
really read the figures. Maybe you have a URL that
has this data published. Like you I mostly operate CW
including some dabbling in CW contests, I never
operate any SSB contest. My interest is also in
performance for performance's sake. I also find the
plasticity of this radio especially in software
interesting.
I ran this radio in the past field day (I got it the
Thursday before Field day, so it was burning a hole in
my operating table waiting to be used)trying to see
how to optimize the various controls and I found the
stock radio essentially bullet proof. I'm not sure
how it would stand up in a multi multi situation, but
from this location once I had the gains pretty well
optimized, I couldn't get it to crap even on the
weakest qrp stuff, (tho I think I did hear the key
clicks sooner, and the crap off the back of the beam
better, than I used to on my old TS-930 I sold 20
years ago :>P) I expect your solution is the most
practical and not nearly as bleeding edge as mine. I
tried running my Pegasus on a second band, and it did
desense the Orion to some extent, but the antennas are
pretty close for this kind of comparison
If the software database is a do-able thing you could
still optimize the system DR, and I expect there are a
lot more guys willing to drop in an after market
filter or 2 than are willing to take a scalpel to the
IF card on their 3500 dollar radio. You could even
trade filter "profiles" over the Internet and maybe
win valuable prizes in "profile shoot offs", but then
who would we get to judge those? The ARRL?
73
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