13 Dec 2009

DSB mod for the Heathkit HW8

When looking around for ideas for DSB rigs I found a page which shows how to modify the HW8 for DSB operation by adding a balanced modulator and audio stages.  KL7R reports that he worked New Zealand using the modified HW8 on sideband.

12 Dec 2009

Received in Norway on 500kHz


Last night, a couple of LA stations were listening on 500kHz WSPR. Neither had heard my 1mW QRP signal by 2300z, so I left the station running through the night. At 0418z LA9BEA heard my signal at -28dB S/N in JO29 square some 836kms to the north east of me. This is now my 8th country, and 49th station, to log me on the band.











11 Dec 2009

NMRevue Magazine (from Belgium)

Just found a link which takes you to back numbers of the NMRevue magazine from Belgium. I'm not sure if this is a club/regional magazine or a national magazine, but it does have quite a few nice constructional articles in each issue. Unfortunately you will need to read French to fully enjoy this.

Rising sea levels - what would happen?

Whatever your views on the causes of climate change, it is a FACT that the Earth is currently warming and sea levels are rising. This interactive map allows you to put in the likely sea level rise, in 1m steps, to see how the coastline would change. Some places are little changed but others are e.g. The Netherlands and the Fens in the UK.

A draft text for an agreement on climate change reduction has been released today in Copenhagen. It needs a lot of work.

10 Dec 2009

Classic 10m DSB TX

There was an article, in 73 Magazine back in the early 1970s, about a simple crystal controlled, 1W 10m DSB transmitter. This was reprinted in a Dutch magazine and in RadCom. The schematic had at least one error (one diode in the mixer wrong way around, that I have corrected here), but it is a useful "ideas" starting point for a DSB transceiver. This circuit used PNP transistors. Today I'd use NPN 2N3904 devices and T37-6 toroids everywhere.

ON/F6CNI on 500kHz

This evening, conditions have been very good on 500kHz with almost continuous reports from GM4SLV up in the Shetland Is 896kms to the north. Also tonight, a new reporter ON/F6CNI in JO20 square at 424kms. His reports were very strong (-2dB S/N). This brings my total to 48 unique reports on 500kHz WSPR.  Tonight I've been using the new version of the transverter on the small, tidy, board (see picture on earlier blog entry today). This should be boxed tomorrow.

SAQ (17.2kHz VLF) reception

This link takes you to a recording of SAQ on 17.2kHz as heard by M0LMH in IO93 square.  It is quite strong when the signal starts. I listened on the Dutch online SDR and SAQ was not as strong there as I would have expected at 1600z. This is a recording of SAQ in Connecticut USA made by Jay W1VD earlier today.

Netherlands to get 500kHz

Full licence amateurs in The Netherlands can opt for an experimental permit to conduct experiments in the band 501-504 kHz with a maximum power of 5 W EIRP and a maximum bandwitdth of 100 Hz. The experiments will start on 1 January 2010 and will continue for one year maximum. News came via Rik OR7T and the RSGB LF reflector.

500kHz transverter rebuilt (and working)

This morning I rebuilt the 500kHz transverter in readiness for putting it in a small case. It fits comfortably on a 4 inch by 3 inch single sided piece of copper laminate built "ugly style". The unit worked first time and it has already received 4 WSPR spots from G3ZJO at lunchtime today.  The car keys give some idea of how small this unit is.

SAQ (17.2kHz) - on line receiver

Dec 10th the transmitter at SAQ (Sweden) on 17.2kHz is transmitting a special CW message. Also there is a transmission on Dec 24th. An on-line SDR in The Netherlands that can be used to listen to this. See  http://websdr.pa3weg.nl/ .  Alternatively, try listening with a simple up-converter or simple VLF receiver. 
Extra transmission on 10th December
In order to celebrate the 100th anniversary of the Nobel Prize to
Guglielmo Marconi and Karl Ferdinand Braun, we plan to be on air on 10th December at 08.00 UTC and 16.00 UTC. No reports are required and no QSL-cards will be given.

Traditional transmission on Christmas Eve 24th December
SAQ will be on air on 24th December at 08.00 UTC. The frequency is as usual 17.2 kHz CW. Reports are welcome and will be confirmed by QSL-cards.