Hi Stefan,

I like the first one (Roger's) but the other  one needs more work!
The TX is QRV on 8270.00709 +- many uHz with a carrier until
the coil arcs again but only with about 0.2 A. Looking forward
to getting more stability and 100 uW ERP.

A Rb standard is on my wishlist and more kg of copper is
in the workshop to make a new coil.  I unwound a pie coil
to make a solenoid.  The inductance was a bit lower but
it seems more immune to arcing.

73 and thanks
Joe VO1NA

On Wed, 7 Jun 2017, DK7FC wrote:

Hi all,

I just played a bit and searched for VLF links in the web.

Found this presentation by G3XBM: http://www.cdarc.org.uk/downloads/presentations/VLF_Through_Ground.pdf

and the website of VO1NA: http://www.ucs.mun.ca/~jcraig/vlf.html

Both of these links were never published here, pity. But now... :-)

There may be more...

73, Stefan