[Lowfer] Beacon Schematic

[KA4SEY]

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
>
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