[PCR-1000] PCR-1000 Front end overload

Tue Sep 7 07:42:34 EDT 2004

Martin,

One thing I forgot to mention is that in the LF/MF band, I used to get
"phantom" de-sense on the front end of the PCR-1000 until I plugged its
power pack into my APC UPS.

No idea why that should make a difference, but it did :-)

Reason that just came to mind, is that the "replace battery" alarm just came
on.  Nuts!!!  That bugger is expensive.  :-(

73's OM

Regards, RJ
----- Original Message -----
From: "Martin Francis" <martin at classaxe.com>
To: "'Discussion of PCR-1000 by Icom'" <pcr-1000 at mailman.qth.net>
Sent: Tuesday, September 07, 2004 7:30 AM
Subject: RE: [PCR-1000] PCR-1000 Front end overload

> Thanks RJ,
>
> I will investigate further.
>
> 73,
>
> Martin
>
> -----Original Message-----
> From: R. J. Grasser [SMTP:rgrasser at frontiernet.net]
> Sent: Monday, September 06, 2004 8:37 PM
> To: martin at classaxe.com; Discussion of PCR-1000 by Icom
> Subject: Re: [PCR-1000] PCR-1000 Front end overload
>
> Hi Martin,
>
> First off.... dont call me "MR" or "SIR"  I havent been a USAF officer
since
> 1964 :-)  RJ is just fine ;-)
>
> I really cannot help you as the overall system is dependent on its
> individual components and their interactions.  few people realise this
> factor.
>
> I find the MJF-1045C to work just fine with my H-800 active antenna, and
> ST-2 broadband dipole array.
>
> While it is not supposed to "function" below 1.8 Khz it does work down to
> 100 Khz with limited effect.  Anything that works down there is  a + :-)
>
> Regards, RJ
> ----- Original Message -----
> From: "Martin Francis" <martin at classaxe.com>
> To: "'Discussion of PCR-1000 by Icom'" <pcr-1000 at mailman.qth.net>
> Sent: Monday, September 06, 2004 7:09 PM
> Subject: RE: [PCR-1000] PCR-1000 Front end overload
>
>
> > Hi there Mr Grasser,
> >
> > I looked up the presector at MFJ's web site.   It seems that it only
goes
> > down to 1.8MHz - great for Hams, less so for NDB / MF DXers.
> >
> > I found another product by MFJ that looked interesting:
> > http://www.mfjenterprises.com/products.php?prodid=MFJ-956
> >
> > If you click on the 'Download the MFJ-956 Manual' link you see a very
> > simple circuit diagram - switchable inductor in series with 365pF tuning
> > capacitor.
> >
> > 1/(2 * PI * sqrt(L*C))
> >
> > The inductors for the bottom couple of bands are 2.5mH and 33uH.
> Assuming
> > a usable tuning range of 40-365pH:
> >
> > 2.5mH gives 166-503KHz.
> > 330uH gives 458-1385KHz
> >
> > If you wanted to rearrange the formula with a known capacitance of say
> 1nF,
> > for a frequency of 1110KHz... you'd need a bigger brain than I have.
I'm
> > hopeless at these things.
> >
> > Now my question is, if this thing is wired to shunt out the unwanted
> signal
> > (i.e. the shunt goes between antenna and earth), and you add extra
> 'stages'
> > to remove other frequencies, or does the whole thing just turn into one
> > almighty mathematical mess?
> >
> >
> > Any ideas?   Or do I have to build it and try it?
> >
> > ?
> >
> > Martin Francis <><
> > =============================================================
> >  NDBList:   Mapmaster, Country Co-ordinator and NDBRNA Editor
> >  Location:  Richmond Hill, ON, CANADA / FN03GV
> >  Antenna:   Twin K9AY 140' loops on 300 feet of coax
> >  Receiver:  ICOM PCR1000 (2.8KHz filter) + DSP-599ZX
> >  Software:  NDBWebLog, WWSU, Argo, Goldwave, SkySweep, NDBRNA
> >  Beacons:   581 received since May 7, 2003
> >
> >  Web Site:  http://www.classaxe.com/dx
> >  NDB Log:   http://www.classaxe.com/dx/ndb/log
> >  NDB Maps:  http://www.classaxe.com/dx/ndb/maps
> >  NDBRNA:    http://www.classaxe.com/dx/ndb/ndbrna
> >  NDBRE:     http://www.classaxe.com/dx/ndb/ndbre
> > =============================================================
> >
> >
> >
> >
> > -----Original Message-----
> > From: R. J. Grasser [SMTP:rgrasser at frontiernet.net]
> > Sent: Monday, September 06, 2004 5:09 PM
> > To: DB Nicholson; Discussion of PCR-1000 by Icom
> > Subject: Re: [PCR-1000] PCR-1000 Front end overload
> >
> > First off ground your radio at the "in ground" side of your water pipe.
> > Your house wiring, or the power meter may not be anything more than a
> > "floating ground".
> >
> > If you have the money, buy an MFJ-1045C active preselector ($67.00 on
the
> > web), as it has a very sharp cutoff notch filter.
> >
> > We also have a 50 KW station about 7 miles from us, but using the 1045C
in
> > conjunction with my H-800 active antenna (10 Khz to 50 Mhz) from LF
> > Engineering, and my ST-2 broadband vertical array (30 Mhz to 1.3 Ghz), I
> > can
> > totally eliminate the offending AM station, and its images/harmonics.
> >
> > RJ (rgrasser at frontiernet.net)
> >
> > Rochester, NY
> > ----- Original Message -----
> > From: "DB Nicholson" <d_nicholson at bellsouth.net>
> > To: <pcr-1000 at mailman.qth.net>
> > Sent: Monday, September 06, 2004 12:09 PM
> > Subject: [PCR-1000] PCR-1000 Front end overload
> >
> >
> > I live less than 3 air miles from a 50kw AM station (WBT - 1110).  Front
> > end
> > overload makes AM band reception useless.  I am using a longwire abt 30'
> > above ground.  Radio is grounded using the house ground at power meter.
> > Someone once suggested using an RC filter to shunt 1110 to ground, but
I'm
> > not sure what components to use, etc.  Any help would be appreciated!
> > TIA,
> > Dave
> > Charlotte, NC
> > ______________________________________________________________
> > PCR-1000 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/pcr-1000
> > Help: http://mailman.qth.net/faq.htm
> > Post: mailto:PCR-1000 at mailman.qth.net
> >
> >
> >
> >
> > ______________________________________________________________
> > PCR-1000 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/pcr-1000
> > Help: http://mailman.qth.net/faq.htm
> > Post: mailto:PCR-1000 at mailman.qth.net
> > ______________________________________________________________
> > PCR-1000 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/pcr-1000
> > Help: http://mailman.qth.net/faq.htm
> > Post: mailto:PCR-1000 at mailman.qth.net
> >
> >
>
>
> ______________________________________________________________
> PCR-1000 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/pcr-1000
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:PCR-1000 at mailman.qth.net
> ______________________________________________________________
> PCR-1000 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/pcr-1000
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:PCR-1000 at mailman.qth.net
>
>