Interesting results. I wonder how different the
results would be though if you were to use a sound
card program like Spectran fed from the line level out
of the Orion (and RX-340) to find the -6 and -60dB
points on the filter passband curve?? This way the
values are a relative measure of the actual level of
recovered audio vs. the level of AGC action that using
the S meter more or less represents.
Spectran can be found at http://www.weaksignals.com/
Duane
N9DG
--- Carl Moreschi <n4py@earthlink.net> wrote:
> I received my Orion today. I decided to take at
> look at the filter shapes
> of several filters in the Orion. I used a crystal
> calibrator signal for a
> constant source and the Orion S meter to determine
> the relative strength.
> Below is the data I got.
>
>
> Filter 6 DB width 60 DB width Shape
> Factor
>
> 100 150 440
> 2.9:1
> 250 240 470
> 1.95:1
> 500 510 820
> 1.6:1
> 1000 980 1160
> 1.2:1
> 1600 1580 1880
> 1.2:1
> 2400 2360 2500
> 1.06:1
> 3000 2930 3270
> 1.12:1
> 4000 3960 4280
> 1.08:1
>
>
> These filters are all very good. I used the same
> procedure on my rx340 and
> found all the rx340 filters have 1.2 :1 shape
> factors, even the 100 hertz
> filter. But the rx340 100 hertz filter has some
> softening of the CW signal
> through it. The Orion 100 hertz filter still sounds
> fine, exhibiting no
> apparent softening of the CW edges. I would say
> the rx340 CW filters from
> 300 hertz to 900 hertz are better than the Orion
> filters of the same widths.
> But the Orion Filters from 1000 hertz and up are a
> little tighter than the
> rx340's.
>
> I also put my 250 hertz crystal filter in the Orion.
> For these simple
> tests, no improvement was seen. I also am seeing a
> 2 S unit insertion loss
> from the 250 hertz crystal filter. I had to adjust
> the center of my crystal
> filter 70 hertz to get it exactly on center in the
> Orion. That means my 250
> hertz old filter I've had for years has always been
> off frequency by 70
> hertz. I will be looking for a situation where the
> 250 hertz filter
> improves things. I'll report it when I find one.
>
> I've tried to be objective in my measurements, but
> my simple measuring
> method may not be perfectly accurate but none the
> less it should give a
> reasonable account of the filters in the Orion. The
> bottom line is they are
> very good.
>
> Carl Moreschi N4PY
> Franklinton, NC
>
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