[1000mp] MP Roofing Filter from INRAD -- hiss reduction needed?

[Mike Schatzberg]

Hello Dale:

If you want to check the difference between the digital product detector,
and the analog detector in the Mark V, it can be turned on and off in menu
7-7.  If you select off, you will be using the analog detector.  I like to
use the 100-3100 setting, with the digital detector on SSB.  This works very
well for weak stations, and seems to improve the signal to noise ratio.

If the band conditions permit, and you want to improve the signal to noise
ratio further, I like to use menu 5-0, and set it to the 8.2-455 position,
to remove the filter from the 2nd IF, and use only the 6.0 filter in the 3rd
IF.  If you do the comparison between the two detectors as above, with the
normal filter selection button lit, you will see a rather dramatic
difference.  I like to use this set up generally, as it also produces the
best fidelity with stronger SSB stations.  If the QRM becomes a problem, you
can either push the IDBT button, and superimpose the digital filters over
the analog positions, or push the NAR1 filter selection, and have the 2.4
khz filters cascaded in place the single 3rd IF filter.

I also have noted that the best signal to noise ratio seems to come with
about a negative 0.180 setting in menu 8-9, r-usbcar.  This also seems to
improve the noise floor noticeably.

Regardless, later this summer, following some other projects, and despite
some criticism that it may not work well, I intend to change all the
switching diodes in both the preamps and front end.  I will finally find out
what PIN diodes do, or don't do for the Mark V.

As long as the new roofing filter is switchable, it certainly looks like it
is a worthwhile change if you suffer from intermod issues.  Even out here in
the country I have one or two signals I would like to see removed, probably
from strong broadcast station mixes.  I also intend to enable the antenna
tuner to work during receive when desired, to improve the Q of the front
end.  I wonder what the reason is that Yaesu doesn't offer that option, I
want to give it a try.

Regards,

Mike Schatzberg
WB2AJI
----- Original Message ----- 
From: "D. J." <dalej2 at mac.com>
To: "All Things Pertaining To The 1000mp Series" <1000mp at mailman.qth.net>
Sent: Tuesday, May 18, 2004 1:14 PM
Subject: Re: [1000mp] MP Roofing Filter from INRAD -- hiss reduction needed?


> I just tried turning of the EDSP in menu 0-9 and I could tell no
> difference in receiver noise, the tone changed slightly but the output
> from the speaker did not, I had a sound level meter on the speaker.
> The antenna input was on a dummy load.  Am I doing it right?
>
> Also, could you provide details about disconnecting the manual notch,
> where did you do it?
>
> tnx
> Dale, K9VUJ
>
> On May 18, 2004, at 9:31, Harry Yingst wrote:
>
> > if you turn off the DSP in the Menus you should hear the hiss quite
> > well
> >
> >
> >
> >
> > --- Pete Smith <n4zr at contesting.com> wrote:
> >> At 10:25 AM 5/18/2004, you wrote:
> >>> Harry Yingst <ab2pn at yahoo.com>
> >>
> >>
> >> Sorry, Harry, I don't understand -- turning *what* off?
> >>
> >>
> >> 73, Pete N4ZR
> >> The World HF Contest Station Database
> >> was updated on April 26, 2004
> >> 2706 contest stations at
> >> www.pvrc.org/WCSD/WCSDsearch.htm
> >>
> >> _______________________________________________
> >> 1000mp mailing list
> >> 1000mp at mailman.qth.net
> >> http://mailman.qth.net/mailman/listinfo/1000mp
> >
> >
> > =====
> > Harry - AB2PN
> >
> > -
> >
> >
> >
> >
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