Designing crystal oscillators

If you want a range "sure fire" crystal oscillator designs to suit fundamental and various overtone modes you should check out the "Oscillators" page on the QuartSLab website. This has details of circuit values and configurations that will really work. Most of these designs are ones I recognise from my days at Pye/Philips PMR, so I know they are reliable and well tried.

SPRAT on CD (GQRP Club)

An ideal, if late, Christmas present is the latest Sprat CD which has all editions of this excellent UK QRP magazine from edition 1 to 140.  Price to members is £4 and to non-members £10 plus postage.

Starting work on the 10m transceiver today

The weather's a bit warmer (0 deg C) so I'm going to start on the local oscillator section of my DSB transceiver today. Will almost certainly use a mixer/VFO or mixer/VXO using a ceramic resonator instead of a crystal. This will allow me to cover a useful part of the band on either CW or sideband and to provide CW offset easily. The DSB modulator will be a matched pair of diodes.

Quote of the decade

"If the climate was a bank they would have saved it", said Venezuelan President Hugo Chavez. "But it is not. And they have not"

See http://news.bbc.co.uk/1/hi/sci/tech/8423822.stm

Pre-Christmas snow - improved 500kHz?

In the East of England we have had a treat these last few days: deep (for us) snow that is crisp and beautiful. We've had about 10cms here with a little more last night and everywhere is a picture. The attached photo is the lane immediately behind my QTH. This is a video of my house from the road in the snow.

Not sure if it is the improved ground conductivity, but my signals on 500kHz have been reported stronger these last few days.

Sunspots for Christmas please Santa

Judging by the last few days we are definitely seeing much increased solar activity at last. Today the sunspot count was an astounding 43, a figure not seen in a VERY long time. Is it too much to hope for some decent F2 openings on the higher HF bands over the Christmas and New Year? Whatever happens in the short term, there is now a high likelihood of a decent improvement in 10m propagation in 2010. Whoopee!

See http://www.solen.info/solar prepared by Jan Alvestad.

500kHz WSPR - when I forgot the ATU!

Having used my 5m long vertical on 40m to work OY9R on QRP SSB this afternoon, I went back onto 500kHz WSPR but completely forgot to connect the ATU, so the antenna was connected directly to the transverter with no matching at all! I only realised this when I got a report from M0BMU some 20dB below that normally received (at -26dB S/N). I've since reconnected the 500kHz ATU and the 500kHz signal is back to normal. The IRF510 survived the gross mismatch.

Climate change: Copenhagen fudge and disappointment

The climate change summit ended in a mess with nothing much of substance coming out of it. Let us hope that a legal binding international agreement can be forged next year, although I have my doubts. The full text of the agreement (can you call it that even?) is available for view.

Whatever your views on the reasons for  rising global temperatures, and the scientific evidence for man's influence on this is now overwhelming, we do need to take steps to put the breaks on further rises. My biggest worry is the risk of the tundra's permafrost melting releasing huge quantities of methane. This would make the CO2 problem seem like a walk in the park. If this happens we could be looking at human life in deep deep crisis. We MUST, and can, take steps to avoid this if the data is made clear to people and we take collective action.

500kHz antenna video

As it was a nice snowy day I took a short video of the 500kHz spiral top loaded antenna that I use for my WSPR testing on the band. The spiral part is hard to see but consists of 8 turns of wire spiralling into the centre on top of the 5m vertical section. There is also a further brief video showing the end of a 500kHz WSPR transmission.

Uk 500kHz permits extended to 2012

Just seen this today on the LF reflector:

Ofcom has decided to extend the period of Notices of Variation (NoVs) to the licence for operation in the 501 to 504 kHz band until 29 February 2012. The maximum effective radiated power (e.r.p.) limit is maintained at 10 dBW (10 W).

Only another 40dB ERP to find then :-)