[Lowfer] Beacon Schematic

Tue Nov 24 16:43:09 EST 2020

Looks good to me, I saw where John D. said that so I will add those in. I
have plenty of resistors here so that's no problem. Thanks for the new
schematic.

Kasey

On Tue, Nov 24, 2020, 4:36 PM John Hamer <wilbur0611 at gmail.com> wrote:

> Kasey,
>
> I looked at the 4060 datasheet and it recommends the two resistors John D,
> was referring to. I guess I should have looked over it before instead of
> making an assumption it was like other things I have done. So, I updated
> the schematic to show the two resistors. I am not sure exactly what values
> to use, but if it doesn't work, we will just have to play with the values.
> Without an oscilloscope, you won't be able to see what's happening, but it
> shouldn't take but a few tries to get it right.
>
> Regards,
> John Hamer
> Lowfer JH
>
> [image: simpltx_mod2.gif]
>
> On Tue, Nov 24, 2020 at 7:14 AM KA4SEY <ka4sey at gmail.com> wrote:
>
> > So I just put like a 10M ohm resistor in parallel with the crystal and
> the
> > two 27pf capacitors in series to ground?
> >
> > Kasey
> >
> > On Tue, Nov 24, 2020, 12:31 AM John Hamer <wilbur0611 at gmail.com> wrote:
> >
> > > John Davis,
> > >
> > > What is the purpose of the resistor between the crystal and pin 10? I
> > > understand the one across pins 10 and 11. I mostly design
> microcontroller
> > > circuits and go by the design recommendations in their datasheet, but I
> > > have never come across that. Though, that crystal configuration seems
> to
> > be
> > > common in these lowfer transmitter designs.  When Kasey was having
> issues
> > > with the oscillator over the summer,  I told him to go to the 2
> capacitor
> > > configuration so we could easily calculate the values from the crystal
> > > datasheet.  I've never had issues with a crystal starting, but I also
> > don't
> > > have much experience with the 4060.
> > >
> > > Regards,
> > > John Hamer
> > > Lowfer JH
> > >
> > > On Tue, Nov 24, 2020, 12:18 AM John Hamer <wilbur0611 at gmail.com>
> wrote:
> > >
> > > > Kasey,
> > > >
> > > > John is correct about the resistor. I did not mean to omit that.
> > > >
> > > > John,  thanks for linking those messages. I was trying to find them
> > > > earlier to show Kasey, but was having trouble.
> > > >
> > > > Regards,
> > > > John Hamer
> > > > Lowfer JH
> > > >
> > > >
> > > > On Mon, Nov 23, 2020, 10:23 PM KA4SEY <ka4sey at gmail.com> wrote:
> > > >
> > > >> John D.
> > > >>
> > > >> John H. has helped me out a lot so I'm hopefully on a good path.
> With
> > me
> > > >> building a new transmitter with all the new things I have learned it
> > > >> should
> > > >> do well. I will still leave room for a LPF just in case but like you
> > > said
> > > >> with the high Q factor it should be fine without one. I'm still very
> > new
> > > >> so
> > > >> any information is helpful. Thanks again
> > > >>
> > > >> Kasey
> > > >>
> > > >> On Mon, Nov 23, 2020, 10:16 PM J D <listread at lwca.org> wrote:
> > > >>
> > > >> > Kasey, I'd really recommend not omitting the 2.2 - 10 meg resistor
> > > >> > between pins 10 and 11 of the 4060, and the series 1 - 1.8 K
> > resistor
> > > >> > between pin 10 and the crystal. Sometimes it'll work without them,
> > but
> > > >> > other times there is unreliable startup or instability to struggle
> > > with
> > > >> >
> > > >> > Other than that, I thoroughly endorse John H.'s recommendations,
> > > >> > particularly the output coupling arrangement and isolation of the
> > > tuning
> > > >> > coil from ground losses. His experiences with those issues are
> > > >> > documented in our discussions of that topic on the LWCA Message
> > Board
> > > >> > last December and January. You can find them in these archives,
> > > >> > particularly the one for January:
> > > >> >
> > > >> > https://lwca.net/mbarchiv/msg1219.htm
> > > >> > https://lwca.net/mbarchiv/msg0120.htm
> > > >> >
> > > >> > The high-Q tank circuit formed by the properly tuned inductor
> > (that's
> > > >> > where an RF current meter will help) and the antenna capacitance
> is
> > > >> > normally more than adequate to comply with harmonic and spurious
> > > >> > emission limits for Part 15 operation at 1750 meters.
> > > >> >
> > > >> > I would include provision on your circuit board to add the LPF
> > > >> > components later, just in case (1) you find harmonics are a
> problem,
> > > and
> > > >> > (2) you are able to actually measure the impedance of the antenna
> > > system
> > > >> > and adjust the LPF values to match. But otherwise, the filter is
> > > likely
> > > >> > to result in more problems than benefits.
> > > >> >
> > > >> > 73
> > > >> > John Davis
> > > >> >
> > > >> > ______________________________________________________________
> > > >> > Lowfer mailing list
> > > >> > Home: http://mailman.qth.net/mailman/listinfo/lowfer
> > > >> > Help: http://mailman.qth.net/mmfaq.htm
> > > >> > Post: mailto:Lowfer at mailman.qth.net
> > > >> > Post must be less than 50KB total for message plus attachment!
> > > >> >
> > > >> > This list hosted by: http://www.qsl.net
> > > >> > Please help support this email list:
> http://www.qsl.net/donate.html
> > > >> >
> > > >> ______________________________________________________________
> > > >> Lowfer mailing list
> > > >> Home: http://mailman.qth.net/mailman/listinfo/lowfer
> > > >> Help: http://mailman.qth.net/mmfaq.htm
> > > >> Post: mailto:Lowfer at mailman.qth.net
> > > >> Post must be less than 50KB total for message plus attachment!
> > > >>
> > > >> This list hosted by: http://www.qsl.net
> > > >> Please help support this email list: http://www.qsl.net/donate.html
> > > >>
> > > >
> > > ______________________________________________________________
> > > Lowfer mailing list
> > > Home: http://mailman.qth.net/mailman/listinfo/lowfer
> > > Help: http://mailman.qth.net/mmfaq.htm
> > > Post: mailto:Lowfer at mailman.qth.net
> > > Post must be less than 50KB total for message plus attachment!
> > >
> > > This list hosted by: http://www.qsl.net
> > > Please help support this email list: http://www.qsl.net/donate.html
> > >
> > ______________________________________________________________
> > Lowfer mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/lowfer
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Lowfer at mailman.qth.net
> > Post must be less than 50KB total for message plus attachment!
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> ______________________________________________________________
> Lowfer mailing list
> Home: http://mailman.qth.net/mailman/listinfo/lowfer
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Lowfer at mailman.qth.net
> Post must be less than 50KB total for message plus attachment!
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html