11th country on 500kHz

Just had a 500kHz WSPR report from MW0CVT 250kms to the west of me. This is now my 11th country from which I've had reports on the band. This is also my 83rd unique report on the band.

Amateur DXing below 9kHz (VLF)

Some recent discussion on the LF Reflector is suggesting that distances of >100kms should be workable with amateur stations below 9kHz, albeit running QRO exciters. This would be possible with optimised stations and antennas and very slow QRSS modes. As an example, see the email posted this evening by RA9MB:

I was wonder if it is posible to use a loop on 9 kHz. Serious problem to radiate 9 kHz is high voltage we saw. Loop has that advantage that voltage is not too high. Then i do some estimations. Let's assume vertical loop 15m x 50 m with 20 mm diameter coper tube as a wire. Then effectivity of such a loop on 9 kHz is about -65 dB. It is adequate to radiate 1 mW
on 9kHz (I=250A, TX power about 4 kW). We saw such a radiation should give abt 100 km  distance in QRSS. Besides such a loop is well suited for 136 kHz. On 136 kHz it effectivity should be about -25 dB. Not too bad: 1 W radiation with 400 W TX :-)

QRP transatlantic on 80m

Just got a report from W1XP on 80m WSPR when running just 1W into the 5m long vertical. DX is 5280kms. Report suggests that 500mW would also have crossed the pond.

New Zealand gets 500kHz (for now)

From March, New Zealand amateurs will be allowed to use 505-515kHz. The number of administrations making temporary allocations is increasing all the time now. Expect some ZL-USA (and maybe Europe?)  tests before long on the band. I wonder who will be the first to receive some 500kHz WSPR beacons from the Antipodes?

Australia on 40m QRP tonight

It really is too easy with WSPR on HF.  Last night some reports from Antarctica and tonight a brief 5W transmission on 40m got me another report from VK6POP in Australia. One of my projects is a micropower WSPR beacon for 10m, but it will have to be something like 10mW to be anything like a challenge :-)

First sub-9kHz NoV application with OFCOM

G7NKS has already submitted his application for an NoV to operate below 9kHz. Mine will be prepared in the next few days. Approval (or rejection) may take some time as OFCOM has to consult with the Met Office first. The Met Office monitors <9kHz for sferic activity to track storms and lightning.

WSPRing to Antarctica on 30m

This evening my 30m WSPR signals got to Antarctica with several reports from the German Research Station DP1POL in IB59 some 13690kms to the south of me. Best report was -18dB S/N suggesting that I would have been copied running just 500mW.

NoV permits for operation below 9kHz

OFCOM has informed me today that, subject to acceptable outcomes of consultation with other sub-9kHz spectrum users such as the Met Office, they will consider issuing NoVs (similar to those issued for 501-504kHz) to existing UK radio amateurs to permit operation at frequencies below 9kHz. Any such operation would be on a non-interference basis.  Application forms should be submitted to Rod Wilkinson at OFCOM (with as much detail as possible) using the NoV form available at http://www.ofcom.org.uk/radiocomms/ifi/licensing/classes/amateur/applications/ofw306.pdf

Lowest frequency commercial/military VLF transmissions?

The two lowest VLF frequencies in use are apparently:

• 11.904 kHz  RSDN-20 network, a Russian navigation VLF system with transmitters located in Novosibirsk, Krasnodar, etc
• 82 Hz  ZEVS system, an ELF transmitter located on the Kola peninsula and dedicated to strategic transmissions to Russian nuclear submarines.

Jean-Louis F6AGR receives both stations near Paris with an E-field receiver consisting of a home-brew receiver fitted with a FET/BJT front end and a 1m long cylinder vertical antenna.

Improved VLF converter

Chris HB9DAO has sent me a copy of his modifications to my SAQ VLF converter that was published a few years ago in SPRAT. His changes make the converter a bit more "bullet proof" in the European environment where there are lots of very strong signals in the VLF-MF frequency range. The schematic is attached.