Hi Stefan, Paul, VLF.
I've heard the sigs at 2 km and detected them using the DK7FC VLF e-probe
and Spectrum Lab at 5 km but not beyond so this is still in the near field.
The aerial current is 20 mA (very approximate) to a 100M wire at 10 metres
average height.
The tuning coil is small, comprising 2 pies about 15cm across and 5mm wide.
The search continues for a couple of km of 0.5 mm enamelled wire to make a
better coil.
The carrier is generated by an AD9851 clocked with a DOCXO at 10 MHz
with the x6 enabled to clock at 60 MHz. The DDS is fed to a TTL 7493
and divided by 16 then gated with a 7404 for keying then to a 4427 driver.
This setup is also used for 2200 and 630m. Markus looked at the OPDS
spectrum (Thanks!) and believes that the carrier stability and path should
be adequate for EbNaut, but eventually I'd like to experiment with gps
locking.
73
Joe
On Sun, 8 Nov 2015, Paul Nicholson wrote:
We're well into the VLF season now so definitely time for
some tinkering.
What's your ERP Joe? If you can send GPS locked carrier,
we can have a good look for it. That would be a start.
--
Paul Nicholson
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