The dsp filtering slopes are normally much steeper than the roofing filter
slopes. What we should be looking at in that video is purely the dsp
filtering, assuming the user hasn't somehow enabled shallow dsp filtering.
Too many unknowns with no control/disclosure about the rig setup in the
experiment.
73,
Barry N1EU
On Wed, Jan 30, 2013 at 5:49 PM, Billy Cox <aa4nu@ix.netcom.com> wrote:
> Bob,
>
> I believe you are discounting how well the "roofing
> filter" really protects the actual "IF" chain?
>
> Given today's platforms, the line is rather blurred
> as many would consider the "roofing filter" as being
> part of the IF chain too.
>
> Not nearly as easy to define as in years past as to
> either the DSP or the "roofing filters".
>
> Not so long ago, DSP was still primarily audio, not IF.
>
> The DSP systems we have today are excellent, but tend
> to still need an additional filter placed ahead in the
> system to prevent overload and other challenges.
>
> Rather interesting to see how Yaesu copied the K3,
> which followed the Orion platform, after the failure
> of their FT2000 platform with it's RX weaknesses.
>
> Of course Rob Sherwood needs to be remembered for his
> work with the Drake platforms that started all of this!
>
> 73 de Billy, AA4NU
>
>
> -----Original Message-----
> >From: Bob McGraw - K4TAX <RMcGraw@Blomand.net>
> >Sent: Jan 29, 2013 12:06 PM
> >To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
> >Subject: Re: [TenTec] Yaesu comparison
> >
> >First I'd say that a roofing filter has little to do with actual receiver
> IF
> >selectivity. In other words, the roofing filter is pre the DSP
> selectivity
> >which would typically be less than the BW of the roofing filter. Today's
> >receivers develop their selectivity in the DSP system.
> >
> >In the referenced video, I could not discern the DSP selectivity of the K3
> >or the FT-5000. The Orion II BW is 520 Hz.
> >
> >
> >73
> >Bob, K4TAX
> >
> >
> >DISCLOSURE:
> >This is to inform all persons, I am a Tentec Ambassador and I receive
> >compensation according to the Tentec Ambassador program. In addition, I
> >serve as a volunteer beta test person to Tentec for the Omni VII, Eagle
> and
> >Argonaut VI radios. I hold no employment relationship, no financial
> >interests nor do I conduct any commercial business, direct or indirect,
> with
> >Tentec.
> >
> >
> >
> >
> >
> >
> >
> >
> >----- Original Message -----
> >From: "Dan Thompson" <w4uh@bellsouth.net>
> >To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
> >Sent: Monday, January 28, 2013 3:05 PM
> >Subject: Re: [TenTec] Yaesu comparison
> >
> >
> >> Here is a You Tube comparing the K3, Orion II, & FT5000.
> >> http://www.youtube.com/watch?v=8SqVBkA535o
> >>
> >> 73, Dan W4UH
> >>
> >> -----Original Message-----
> >> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of
> >> k4elo@fastmail.fm
> >> Sent: Sunday, January 27, 2013 6:47 PM
> >> To: tentec@contesting.com
> >> Subject: [TenTec] Yaesu comparison
> >>
> >> Has anyone on the list had the chance to do an A/B comparison between
> >> the Orion II and the Yaesu FTdx5000? Particularly in terms of ssb
> >> selectivity.
> >>
> >> I used to have an Orion II and sold it (bad move!), but now much later,
> >> have a Yaesu FTdx5000, but I am not satisfied with it's selectivity,
> >> maybe due to only a 3 kHz roofing filter. So I am seriously thinking of
> >> going back to the Orion with a 1.8 roofing filter.
> >>
> >> Any comments?
> >>
> >> Thanks and 73
> >> Wayne
> >> K4ELO
> >>
> >>
> >> _______________________________________________
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> >> TenTec@contesting.com
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> >>
> >>
> >> _______________________________________________
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> >> TenTec@contesting.com
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> >>
> >
> >
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