No..........
Dynamic range can only be measured with a spacing attached to it.
Traditionally it was 20 kHz but is frequently now measured at 5 kHz. That's
why roofing filters can improve dynamic range. Inside the filter b/w you
are always at the mercy of the raw dynamic range of the other circuitry
whether that be digital or analogue.
In short.... John is absolutely right. You will improve significantly the
dynamic range of the TS870 at both 20 kHz and 5 kHz spacing by shoe-horning
a pair of Inrad 2.7 kHz filters into the 2nd and 3rd IF of the 870. I have
done it and so have many others. Of course dynamic range within the 2.7 kHz
b/w of the Inrads stays pretty much as it was before.
So there you go........
Bob, 5B4AGN
----- Original Message -----
From: "Ken Brown" <ken.d.brown@verizon.net>
To: <tentec@contesting.com>
Sent: Thursday, September 02, 2004 5:22 PM
Subject: Re: [TenTec] Re: [Ten-Tec] Alas, not for me
> John Rippey wrote:
>
> >
> > E. Alternatively, it's possible to modify a TS-870S by shoe-horning
> > INRAD filters in place of the stock 2d and 3d IF filters, and this
> > produces a radio with pretty good dynamic range.
>
> Excuse me John, but this sounds wrong to me. The dynamic range is
> limited by the analog to digital converter. Narrowing the bandpass that
> the ADC sees does not increase it's dynamic range, although it may
> decrease the need for a large a dynamic range. So then what was not good
> enough may then become pretty good. Still the dynamic range is the same.
> If the little signal you are trying to copy and the big signal you want
> to reject are both inside the (narrower than stock) roofing filter
> bandwidth, your ability to separate them is still limited by the dynamic
> range of the ADC. Since with a narrower roofing filter you have less
> total power to digitize, you can get away with a smaller dynamic range a
> lot of the time.
>
> DE N6KB
>
>
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