More Chromebooks

The new Acer C7 Chromebook on the
www.cnet.com site

A few weeks ago I mentioned the Samsung Series 3 Chromebook which is available in the UK for £229. Now I see there is a new entry, the Acer C7 Chromebook which retails for just £199 here and $199 in the USA. This sports a 320GB hard drive and, like the Samsung, a high resolution 11.6 inch display.

The main drawback (or is it an advantage?) of a Chromebook is that it uses the Chrome OS and depends a lot on cloud based applications, although quite a lot of applications work off-line too these days.

Certainly for a second PC at home and on the move it has to be a good bet.

472kHz WSPR this evening

After the CW QSO and 500kHz WSPR TXing this evening I switched over to 474.2kHz USB dial WSPR receiving, whilst I watched "Homeland" on TV (BTW, this is a truly excellent US drama series - I don't usually like US dramas). Good signals coming through from the usual suspects, HI. The weaker signal at the bottom of the image is DF2JP.

474.2kHz WSPR this evening

It sounds like the first UK access to the 472-479kHz band will be for old 500kHz NoV holders, which includes me, on Jan 1st 2013. It is NOT likely the band will be generally available in the UK at that time, but some time later. Even the 500kHz NoV holder access to the new band is not yet certain on Jan 1st 2013. Watch this space!

CW QSO with M0FMT on 500kHz this evening

After the usual reports from all over the place on my 50mW ERP 500kHz WSPR I took a listen around for some CW stations this evening. G3XIZ was calling CQ and listening on 80m crossband, but then I heard Pete M0FMT not too far away in Hitchin calling CQ. He heard my reply and gave me 529 report. He was about 549 with me deep in the noise that remains on the band. A few days ago this QSO would have been impossible because of the local noise here. The offending noise source (central heating controller SMPSU) is switched off!

Barbados on 10m QRP

8P6BX in Barbados

Whilst looking for QSOs with Lesser Chirpy on 28.060MHz this afternoon I heard Ron 8P6BX in Barbados calling CQ. No go with 70mW so I turned on the FT817 and worked him with 5W getting a 569 report. He was running 3W and was peaking 589 with me. It was a nice, solid 2-way QRP QSO on CW.

Autumn projects - an update

Well, I don't seem to be getting on too well with my autumn project list! The 472kHz transverter got finished, as did the WSPR beacon rig for 10m. I also managed some VLF earth-mode work. However, I've still to get back to the 481THz (lightbeam) over-the-horizon tests using the new higher power Phlatlight 5W LEDs. Neither have I rebuilt my 10m halo or erected a proper RX antenna for LF and MF. Mind you, I've added a new project, the Tenbox 10m AM transceiver, which is progressing quite well so far.  In the end it doesn't matter what gets done and when as long as I'm enjoying the hobby and experimenting with simple ideas.

Burwell Steven's Mill © Copyright Rodney Burton and licensed for reuse under this Creative Commons Licence.

Around the middle of 2013, if things go to plan, we are moving home to a bungalow in the same village which is located on the "hill" (this is a relative term in East Anglia!) next to Burwell windmill and museum. The windmill has just received a National Lottery grant and should be fully restored to full working order with 4 sails. This will be about 20m from our front door! I'll expect to be asked to do a "windmills on the air" weekend, HI. Burwell Museum is really something quite special and well worth a visit.

With what will be a much better VHF and UHF take-off I will be tempted to get much more active DXing on 2m, 70cm and 23cm from the new QTH. This is likely to bring a whole new set of challenges.

Lesser Chirpy spans the Atlantic (10m QRP)

My 28.060MHz ultra-simple QRP transceiver was copied in the USA this afternoon. K3MM (Maryland) reported me on the Reverse Beacon Network as 7dB S/N at 15wpm on 28.060MHz. K3MM is in FM19JH which is 5886km away.

Initially I was unable to hear any stateside stations to call for a QSO. Still, the rig has now been copied across that big ocean! Power out into the halo is around 70mW.

VE2TH was coming through OK with 5W and might have been workable but the band faded out.

Testing the Tenbox on 10m AM today

Today I wanted check how good the Tenbox 10m AM receiver (part of the intended transceiver) was in real use as opposed to measuring it on a signal generator.

So, I set up my FT817 on 10m AM TX on the lowest power setting, which is around 150mW carrier, and fed this into a makeshift vertical tuned with the T1 ATU. Using my PC, I made a short message "G3XBM testing on 10m AM" that I played in auto-repeat.

I then went for a drive locally with the little super-regen RX in the car being fed from a vertical mag-mount antenna on the car roof. The only antenna I had was an ATX15 base loaded whip for 15m, so I pushed a few sections in to make it resonate on 29MHz.

Results were encouraging. Out in the car my 150mW AM TX beacon message could be copied out to about 2 miles away, although this was limited by QRM from W2VW (!) and VE3OWV (!) who were coming through with 59 signals on the RX on 29MHz AM. When they dropped carriers copy was fine. It's fascinating to think my 150mW AM signal was having QRM from 5000km away!

A super-regen is not really suitable for use when 10m is wide open, like it was this afternoon. Nonetheless I was able to copy stateside stations on 10m AM on a short base loaded mag-mount pretty well. For its intended purpose as a local across town natter box, I think the Tenbox is going to be fun. With 6dB more power out (my aim for it) it should be certainly possible to work G6ALB 3km away in the next village.

The next stage is now to build the TX part and test this.

After the noise: 160m CW QSO

Following my small successes last night battling my local man-made noise sources, this evening I managed nearly a full QSO with GW0IRW on 160m CW when running 5W to my vertical coax to the 10m halo. The noise level is now low enough to sensibly copy stations on 160m, which I've not been able to do for months at night.

I am now monitoring 474.2kHz WSPR hoping to improve on my reports now the local noise floor is much lower. SM6BHZ is already coming in at a respectable -14dB S/N. He is usually pretty strong so it will be interesting to see how many others come through this evening.

Winning the noise battle a step at a time

This evening I've been trying to track down various noise sources that have been making reception on MF and the lower HF bands all but impossible in recent weeks. I'm pleased to report a couple of successes.

My first "trap" was the 12V Netgear AD6612 AC-DC adaptor that feeds my Virgin Media internet superhub. This little terror was producing an S6-8 noise floor on many of the lower ham bands. I tried ferrite chokes in the leads but to no avail. Fortunately I had an old Linksys 12V supply with the same sort of rating and 12V plug. Swapping the PSUs over and, guess what, the lower HF bands were much quieter once again.

At 470-500kHz though I still had an S8 noise floor, so there was another candidate noise generator around. Switching everything off in the house the noise floor dropped, so it was in the house. In the end I tracked this down to a Salus mains powered controller that receives wireless signals from the central heating roomstat. Turning this off and, guess what, 470-500kHz goes much quieter too! This unit is quite close to my antenna wire and must have a noisy SMPSU inside. Luckily we tend not to have the central heating on in the evening so all I have to do is turn off the Salus wall unit controlling the central heating boiler and I can, I think, go back to better reception on the MF bands in the evenings.

In 30 minutes I've reduced the noise floor in my home considerably from LF to at least 10MHz. This goes to prove that with a little bit of detective work we can do a lot to overcome many of the noise issues plaguing us these days. Both the Virgin Media superhub and the Salus unit are new (less than 6 months old) so this also explains why the noise issue was not such a problem last autumn and winter.

If you have a noise problem then I recommend you do some detective work and very good luck.

Coils for projects

Many of the old TOKO range of coils are hard to find these days but an alternative source for many of these is now available from Spectrum Communications in the UK. See http://www.spectrumcomms.co.uk/Components.htm for more details. If you are a member of the GQRP Club, many of these are available through its excellent club sales. An example, the 45uH coil specified in my 472kHz transverter is available from the above suppliers.

Spectrum also sell a useful range of crystals as well as some of the harder to find, once common, MOSFETs.