[1000mp] UPGRADE BY OE3HKL

[Mike Schatzberg]

Hello Amp Fans:

I spoke with Kurt, OE3HKL, on June 21, 2005, and he is on vacation right
now, away from home.

Kurt says that he did not find an improvement in IMD following the
installation of his new roofing filter in his Mark V Field, and he set about
trying to discover the cause and cure.

He believes from his tests that his 12 Khz factory roofing filter is
different from those filters found in the Mark V (200 Watt) models, and that
the intermod problem already exists by the time the signal passes thru the
original filter.  He does not think that the problem exists within the Mark
V radio because of all the testing done by the ARRL and the RSGB on the 200
Watt version.

Thus, it is necessary to relocate the Inrad filter to just after the first
mixer, rather than just place it in series following the original 1st IF
Filter.

I wondered myself after thinking about this if indeed the part numbers for
the two original filters are indeed different in the two versions of the
Mark V?  Maybe rather than his modification, one could replace the Field's
1st IF filter with the one from the original Mark V, and just add the Inrad
filter in series?  Or perhaps there is some other issue here, beyond a
difference in filters?  Perhaps there is some difference in the quality of
all of the 1st IF filters used by Yaesu?

Kurt's article will be available only in German, and will need to be
translated, as there is no English version at this time.

His measurements following the mod are most impressive, and his modification
does apparently improve the IMD numbers and dynamic range, following
hundreds of experimental hours by Kurt.

I hope to correspond via mail with Kurt and obtain some more information, as
he currently does not have email capabilities.

Regards,

Mike Schatzberg
WB2AJI
----- Original Message ----- 
From: "ON4ADZ" <on4adz at pro.tiscali.be>
To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
Sent: Sunday, July 03, 2005 4:52 AM
Subject: RE: [1000mp] UPGRADE BY OE3HKL


> Dear Uwe,
>
> With tanks !!
> Keep me informed of your improved board.
>
>
> Dirk
>
>
> -----Oorspronkelijk bericht-----
> Van: 1000mp-bounces at mailman.qth.net
> [mailto:1000mp-bounces at mailman.qth.net]Namens Uwe Egen
> Verzonden: zondag 3 juli 2005 9:50
> Aan: All about Yaesu 1000mp
> Onderwerp: RE: [1000mp] UPGRADE BY OE3HKL
>
>
> Hi Dirk,
> BTW the modification is not easy to do.
> Mainly putting the Inrad Roofing Set direct
> after the first mixer and decoupling it.
> If I have time, I will make a better PCB
> for me.
> Will scan both issues. Wait two days.
> 73, Uwe, DL9NC
>
>
>
> "ON4ADZ" <on4adz at pro.tiscali.be> schrieb:
> > Dear Uwe,
> >
> > Can you scan the articles ?
> >
> >
> > With thanks
> >
> > DIRK on4adz
> >
> > -----Oorspronkelijk bericht-----
> > Van: 1000mp-bounces at mailman.qth.net
> > [mailto:1000mp-bounces at mailman.qth.net]Namens Uwe Egen
> > Verzonden: zaterdag 2 juli 2005 9:58
> > Aan: All about Yaesu 1000mp
> > Onderwerp: Re: [1000mp] UPGRADE BY OE3HKL
> >
> >
> > "ON4ADZ" <on4adz at pro.tiscali.be> schrieb:
> > > Dear
> > >
> > > In the june issue of FUNKAMATEUR is the first part of an article by
> OE3HKL
> > > wich describes
> > > a modification for improve the imd performance of the Mark v receiver.
> > > The second part will be published in july.
> > > In this case a Field model.
> > >
> > > The improvement is several db added to the roofing upgrade @2khz
> > >
> > > Has someone more info on modification e.g. the email adres of oe3hkl ,
> > Kurt
> >
> > Dirk,
> > I own both issues of Funkamateur. May I can help you.
> > Uwe, DL9NC
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