29 Apr 2012

More 10m DX and some Es

500mW 10m WSPR results - ZS6BIM best DX
Today I ran my 10m WSPR beacon at 500mW into the wire halo antenna. Conditions were quite reasonable with some good DX reports. Later there was a first sign of sporadic-E propagation around Europe - a sign of things to come for the next few months. I did try beaconing at 50mW for a little while but propagation had deteriorated so no reports were received this time.

28 Apr 2012

Amateur radio history DVD?

The ARRL has produced a DVD recently on the history of amateur radio in the USA over the last 50-60 years. See http://www.arrl.org/shop/The-ARRL-Film-Collection/ .  I wonder how much material exists on old film and video in the UK/Europe and whether there would be enough to make a DVD on the history of amateur radio on this side of the pond?

As I mentioned a few years ago, there was (once) a 78rpm sound disc made by G5UM of the last night of UK operation on the old 56MHz band back in the 1940s, but this appears to have been lost. Although there have been several books on the early history it would be wonderful to find and collate old film material on amateur radio in Europe.

Win XP PC - a full restore?

My main Windows XP laptop PC is now around 6 years old. It has a small 32GB hard drive and my own files occupy around 8GB of this, yet the PC says the C drive has only 3.8GB spare. There is a small back-up partition (about 3GB) and the rest must be program files and Microsoft bloat accumulated over the years. I've already done defrags several times and deleted all the files I know are safe to delete. CCleaner is also regularly run to sort out registry issues and I have compressed files where possible. McAfree anti-virus seems to do a decent job of keeping out the malware.

Although I hope to invest in a new PC soon, I'm considering doing a full system restore back to original factory settings in the hope of recovering all the lost/wasted space.  A full restore will need a few days of work to reload updates (SP2/3 etc) but there must be a lot of unnecessary rubbish there which would be cleared by a full restore.

My plan is to use this "old" PC to run WSPR and some VLF programmes and use a new PC for everyday tasks.

Apart from the usual back-up of any photos and data that are important, does anyone have any advice before I go ahead?

Better 10m conditions


Today I put my 5W 10m WSPR beacon on for a few hours during the day and was rewarded with reports from CX, PY, 5Z4, 4X, LB and G stations. Conditions appeared better than I have noticed in some while and this is proved by a look at recent sunspot activity. See http://www.solen.info/solar/ .

26 Apr 2012

Google Drive (bye bye Dropbox issues)

With the introduction of Google Drive, an online storage facility, I can at last overcome my issues with Dropbox and my VLF grabber. With Google Drive one can store up to 5GB free and more for a fixed price. With the PC or Mac add-on, the drive appears as a file(s) on the computer into which documents can be saved in the normal way. These then appear/sync on any PCs when you sign in to Google Drive.

The bonus is that you can make any file public and get a URL that others can go to. This means that a saved .jpg screen shot of a VLF grabber can be saved to a unique filename on the PC which then is visible to the world if they know the URL. From a webpage I can point people to the URL and they can see the screen grab as it is updated regularly.

I could do all this with Dropbox until about 4 months ago when it started playing silly and refused to sync on my WinXP PC complaining of a registry issue. Despite trying all sorts of recommended fixes none worked and I gave up on Dropbox.

In the coming weeks I will be mounting a more permanent E-field probe which will be connected to the PC whenever it is running and the VLF spectrum view(s) will be available on my sub-9kHz website.

25 Apr 2012

Email questions

As my blogsites and websites attract quite a few visitors, I get a good number of emails from people asking me questions about my projects/thoughts. Whenever possible I try to respond to these right away but occasionally, for example when I am on holiday or have filed the email in the wrong place before answering, I don't reply. Please accept my apologies and write again if after a week or so you've not had an answer.

My standard answer when people ask advice about my circuits is that they are never guaranteed and some experimentation will be needed in any particular implementation layout. The circuits worked for me and should for you if you are prepared to "tweak" values a little.

24 Apr 2012

50MHz UK Activity Contest

This evening I have been listening (and having a few 5W QRP QSOs) in the RSGB 50MHz Activity Contest. This is a good opportunity to find out how effective my wire halo in the loft is. Well, I have worked the locals (G6UW, G3PYE/P and G4BWP) and managed a "QRZ the CW" from G3MEH about 50 miles away. I suspect the results would be several dB better with the halo further up in the air co-located within my 10m halo on the external mast.

Elecraft KX3 production ramp up

Elecraft KX3 units are starting to make their way into customers' hands now, although the initial product rate has been quite low. On the KX3 Yahoo Group there have been a few reports of initial huccups although this is to be expected in any new production run and, as always, Elecraft has handled these very well. According to Wayne Burdick, production is soon expected to ramp up now these initial problems are being ironed out. Wayne writes:
"Off the top of my head....  We had one unit with a dead MCU clock crystal (extremely rare). One radio wouldn't turn off because a mic wire was touching another component (we're looking at heat shrink for that). Two had problems with EEPROM due to a firmware bug I found and fixed at 1:30 AM on Monday morning. This firmware is already in beta test. 

Mostly just new-product syndrome. We really are on the verge of serious shipping increases."
 I have still to decide if/when to order one. The initial reviews on www.eham.net have been excellent.

18 Apr 2012

Low cost rotator

In my search for a low cost rotator for small and lightweight VHF/UHF yagis I see that Conrad Electronics UK sells an "external TV rotator" for £52.99, plus postage from Germany with a free 2 year warranty.

3 core cable, 70 secs 360 deg rotation, 45kg load, 300Nm bending moment, 21.6Nm torque.  See eBay item 180832166179.

Does anyone have any experience of this rotator?

16 Apr 2012

Rotators or big wheels

There was a time when a small rotator capable of turning a modest 2m yagi could be bought for around £40 but there appears to be little available now below £300. The low cost Yaesu rotator (G250?) appears to be unavailable now.  I was thinking about erecting small beams for 6m, 2m and 70cm and was wondering about suitable rotators, but am rather put off by the costs.

A better alternative may be a big wheel antenna with around 3dBd gain omnidirectional, or more if two are stacked. 5dBd is at least as much gain as an HB9CV without the worry of a rotator.