Hi Joe
No...the Sherwood data is for the stock FT1kMPs. So far as I'm aware there
isn't yet any independent data at 2 kHz for the MPs with the Inrad roofing
filter.
Bob, 5B4AGN
----- Original Message -----
From: "Joe Giacobello" <k2xx@swva.net>
To: <tentec@contesting.com>
Sent: Friday, September 03, 2004 9:59 PM
Subject: Re: [TenTec] Re: [Ten-Tec] Alas, not for me
> Bob, are Sherwood's data for the FT1KMPs with the 4 KHz Inrad roofing
> filter installed?
>
> 73, Joe
>
> Bob Henderson wrote:
>
> >----- Original Message -----
> >From: "John Rippey" <w3uls@3n.net>
> >
> >
> >
> >>Finally, with the new roofing filters forthcoming from INRAD, a bunch of
> >>older radios soon are going to have sterling dynamic range capabilities,
> >>and you won't have to jump through hoops like the mods required on the
> >>TS-870, or shell out big bucks.
> >>
> >>
> >snip
> >
> >
> >>I wonder if George's new filters will have the effect of discouraging
> >>introduction of new ham rigs since the older ones are being given such
> >>powerful new legs?
> >>
> >>
> >snip
> >
> >This will be an interesting one when the full story is told. Certainly
so
> >far as the FT1kMP is concerned. The roofing filter from Inrad has a 4
kHz
> >b/w which makes quite a good choice for SSB but is a lot of b/w for CW.
> >Interestingly, the filter requires some additional amplification to get
over
> >its insertion loss and I understand that Inrad have opted to include
enough
> >amplification to get over that loss and add a little bit more. What
price
> >that extra amplification?
> >
> >Figures published by Rob Sherwood
> >
> >http://www.sherweng.com/Dayton_2004/Dynamic_Range_Data.pdf
> >
> >show the following dynamic range numbers at 2 kHz:-
> >
> >TT-Orion 1 kHz roofing 92db
> >FT1k MkV 70db
> >FT1k 69db
> >FT1kMkV Field 60db
> >
> >Sherwood also states that an additional 6-7db improvement in IMD at 2 kHz
is
> >obtained with the Inrad 762 filter. This puts Orions range at 2 kHz up
to
> >98db or better. That's a full 28db better than the FT1k MkV and 38db
better
> >than the Field.
> >
> >That's a big gap and one that can only widen when the roofing filter mod
is
> >added. The question is by how much? As a CW man, I wonder whether the
> >benefit in improved IMD at 5 kHz will outweigh the deterioration in IMD
at 2
> >kHz. I have an MP but for now my roofing filter dollars will stay in my
> >pocket. Time will tell.
> >
> >Bob, 5B4AGN
> >
> >
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> >
> >
> >
> >
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