[1000mp] W2VJN Comments on Roofing Filter IF Adjustment

[Mike Schatzberg]

Hello Pete:

Well, comparison testing has already been done, and published, on the before
and after results of the Inrad mod,
with adjustments having been made in the IF gain menu to equalize the S
meter reading after the mod.  You probably
have seen the QST review, but I think this review made with the reduction to
the IF gain in menu 9-1 is more real world.

If you are interested in the data, published by Peter Hart, G3SJX, a
reviewer for RadCom, the RSGB
publication, I would be please to provide that information off list.

His data confirms what has been posted here in the past.

Regards,

Mike Schatzberg
WB2AJI
----- Original Message ----- 
From: "Pete Smith" <n4zr at contesting.com>
To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>; "All about Yaesu
1000mp" <1000mp at mailman.qth.net>
Sent: Tuesday, February 01, 2005 4:53 PM
Subject: Re: [1000mp] W2VJN Comments on Roofing Filter IF Adjustment


> For what it is worth, this quietness business has always been a subject of
> some debate; there are technically competent people who argue forcefully
> that the gain redistribution accomplished by the IF mod and the later
> roofing filters may actually degrade IMD performance while improving
> MDS.  But I do wonder whether Inrad feels that the later roofing filter
> units really do offer the same improvement in MDS as the IF mod.
>
> 73, Pete N4ZR
>
> At 03:57 PM 2/1/2005, Mike Schatzberg wrote:
>
> >Hello Pete:
> >
> > >From an insertion loss point of view, permitting a significant
reduction in
> >IF gain setting, in menu 9-1, and thus accomplishing both the stated
> >promised improvements in IMD reduction, whiskering, etc., as well as the
> >unstated improvement in noise floor reduction.  The later production
units,
> >which may have the lower insertion loss crystal filters,  as perhaps does
> >yours for all anyone knows, will function to serve as both mods ( roofing
> >filter and IF amp) at once.
> >
> >This does not mean the earlier filters do not work.  The later ones
> >apparently further improve the quietness of the receiver also.
> >
> >Regards,
> >
> >Mike
> >----- Original Message -----
> >From: "Pete Smith" <n4zr at contesting.com>
> >To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>; "All about Yaesu
> >1000mp" <1000mp at mailman.qth.net>
> >Sent: Tuesday, February 01, 2005 3:37 PM
> >Subject: Re: [1000mp] W2VJN Comments on Roofing Filter IF Adjustment
> >
> >
> > > I do not understand this statement.  Do you mean late-production
roofing
> > > filters are better, or what?
> > >
> > > If the former, then I doubt George would agree with you.  I have a
second
> > > run roofing filter, and certainly feel it is a huge improvement in my
Mark
> >5.
> > >
> > > 73, Pete N4ZR
> > >
> > > At 02:52 PM 2/1/2005, Mike Schatzberg wrote:
> > > >The newer crystal filters are working incredibly well, far more
> >efficiently
> > > >than the earliest units which were produced by Inrad.
> > >
> > > ______________________________________________________________
> > > 1000mp mailing list
> > > Home: http://mailman.qth.net/mailman/listinfo/1000mp
> > > Help: http://mailman.qth.net/mmfaq.html
> > > Post: mailto:1000mp at mailman.qth.net
> >
> >______________________________________________________________
> >1000mp mailing list
> >Home: http://mailman.qth.net/mailman/listinfo/1000mp
> >Help: http://mailman.qth.net/mmfaq.html
> >Post: mailto:1000mp at mailman.qth.net
>
> ______________________________________________________________
> 1000mp mailing list
> Home: http://mailman.qth.net/mailman/listinfo/1000mp
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:1000mp at mailman.qth.net
>