[time-nuts] Firmware and antenna for Stanford Research FS700 Loran C frequency standard

Poul-Henning Kamp phk at phk.freebsd.dk
Thu Jul 16 12:23:08 EDT 2015


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In message <CANX10hBuaHDwaChb+wHLKen4wcwn5_R2UEn9aJZmnvL8AxZe4Q at mail.gmail.com>
, "Dr. David Kirkby (Kirkby Microwave Ltd)" writes:

>but roughly how many turns were there on the coil?

Probably too many, all things considered, but I have *no* idea.

>Do you have a circuit for the amplifier?

It was based on/inspired by a schematic I found on vlf.it

>I must admit to knowing next to nothing about antennas at the Loran 100 kHz
>(+/- a lot) frequency. How does one go about testing the antennas? 

Plug it into a spectrum analyzer or oscilloscope.

Use average mode.

Trigger with a pulse generator with a period of:

	 6731 * 2 * 10µs) = 0.13462 Hz

and you should see the pulses.

If you have a good spectrum analyzer, you can probably do this with
a few meters of wire as antenna.

The result should look something like:

	http://phk.freebsd.dk/misc/dscf0275.jpg


>That's the only thing I have got that measures impedance as low as 100 kHz.

100 kHz is practically audio, impedances hardly matter: The reflections
have wavelengths measured in km.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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Never attribute to malice what can adequately be explained by incompetence.


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