VLF success at last for G3XIZ (37km on 8.97kHz)

Chris G3XIZ achieved some VLF success today when his 50m high balloon supported vertical driven with around 50W was copied at up to 15dB S/N by M0BMU at a distance of 37km. Mode used was QRSS600. This is a new UK record for an amateur VLF transmission and is the first confirmed "far field" radiated signal. Well done Chris.

M0BMU estimated the ERP as follows (from a posting to the LF-reflector by Jim):

"I made an estimate of the field strength of your signal by injecting a test signal at a known EMF into the loop antenna, and comparing with the level of your signal. The received FS at the strongest point (around 1330utc) worked out to be 1.8uV/m. Taking the distance between our locations as 37km, your ERP would have been 87uW. The SNR at best was around 15dB, making the noise level 0.32uV/m in the FFT noise bandwidth of 2.1mHz, or a noise density of 7uV/m per sqrt(Hz)


Assuming a 50m vertical wire (heff ~ 25m),  Rrad of your antenna at 8.97kHz would be 880micro-ohms. Assuming 2.62dB directivity for an electrically short monopole compared to a dipole, and Iant of 200mA, the calculated value of ERP would then be 64uW. So there is reasonable agreement between these two calculations, the difference only being 1.3dB."

Night time SAQ VLF transmission - Jan 4th 2011

There will be an extra transmission with the Alexanderson alternator on 17.2 kHz primarily for listeners in North America, the times shown below. QSL cards will be issued for correct reports. These can be sent via post, email or via the SM QSL bureau.

16:00 PST (Pacific Standard Time) in USA. Monday, Jan 3rd, 2011 

19:00 EST (Eastern Standard Time) in USA. Monday, Jan 3rd, 2011

00:00 UTC (Coordinated Universal Time) Western Europe. Tuesday, Jan 4th, 2011

01:00 CET (Central European Time) and local time in Sweden. Tuesday, Jan 4th, 2011

Diurnal Variation in Dreamer's Band Noise

Over the next 24 hours I am doing a test to measure the change in VLF noise floor between 0-24kHz. DK7FC has let me have a suitable .usr file for Spectrum Lab to allow this to be recorded. You can see the results on the G3XBM VLF grabber which is updating the plot every 15 minutes.

Surprise late afternoon 10m opening to the USA

WSPR reports 10m on 28.12.10

Late this afternoon I was surprised to see that 10m opened up to the USA and that my QRP WSPR beacon was being received well at up to 6991km with reports at 5692km from K3ZV as late as 1800z with my reports of USA stations being the last ones to appear, meaning I was receiving stations when others were no longer doing so. Power was 5W and the antenna the Homebase-10 wire halo.

G3XIZ on 8.97kHz today

Chris, G3XIZ was testing on the Dreamer's Band again today and I was monitoring some 34km to the east. Unfortunately, this attempt was also unsuccessful with no copy here in East Cambridgeshire.

Iceland get big 500kHz allocation

493-510 kHz has been granted on a secondary basis to amateurs in Iceland with a power limit of 100W. In addition, 60m and 4m allocations have also been confirmed.

Dutch hams lose 500kHz (for now)

Stations in The Netherlands who were active on 500kHz will have to stop transmitting at the end of 2010 as their permits have yet to be renewed. It is expected that this will happen within 4-6 weeks.

Christmas WSPRs

Very quiet on 10m WSPR today, Christmas Day. Just G3JKV coming through from 123km to the south of me on tropo. WSPR is an ideal mode for Christmas day as one can set it running, go eat the turkey and trimmings and periodically check results.

Merry Christmas everyone

Whatever your circumstances I hope you have a peaceful and happy time this Christmas shared with the people you love.

G3XDV on 136kHz QRSS

Getting a very strong signal this evening from G3XDV on 136.177kHz QRSS60 receiving Mike on the earth electrodes fed straight into the deaf (at 136kHz) FT817. He is sending "XDV" preceded by G3XDV in normal speed CW.