Chromebooks?

This week saw the launch of Windows 8. Also, Google launched a new Chromebook 11.6 inch PC manufactured by Samsung which is getting rave reviews. Chromebooks use Google's Chrome OS which is very much linked to Cloud based operation.  The new series 3 Chromebook is only £229 from John Lewis complete with a 2 year warranty. In the USA it is available for $249. Now, when I looked I could not see any amateur radio apps for this OS. They will surely come though.
UK retailers include PC World, Amazon and John Lewis. They seem to be selling FAST.

Although I am not sure why, this PC really appeals to me: it is simple, small and effective. The local machine remains uncluttered and safe to use as most of the applications work remotely "in the cloud" although Gmail, Goodle Docs and lots of other apps will work without an internet connection too.

Has any reader used a Chromebook? What were your impressions?

VLF DX radiated test results

My days long, continuous carrier test with G3WCD (32km) and G3ZJO (around 50km) around 8.977188kHz ended yesterday. I was using my 20m spaced earth electrodes with 5W out of the PA. The test was to see if anything at all could be detected well beyond the 6km I can repeatably obtain with QRSS3 earth-mode (through the ground) communications.  Despite the hint of a signal a couple of times on the G3WCD 45uHz and 22uHz grabbers, these proved to be false signals and nothing was detected.

Using Spectrum Lab, locked to a VLF MSK signal I am able to measure my TX frequency with VERY great accuracy, in fact to an accuracy of less than 1mHz. What this showed up was that my crystal controlled TX drifted (very slightly by HF VFO standards) about 13mHz over the 4 days of the test. Starting frequency was around 8.977177kHz and the final frequency 8.977190kHz. With shack temperature variations it may have moved slightly higher or lower too.

When the RX stations are looking for a very very weak signal in a bandwidth of 22uHz this means the signal is only "within band" for the FFT software to analyse for a brief period before drifting out of the measuring "bucket".  To have ANY chance it will be essential for me to lock the TX frequency so that it stays within a few uHz over a period of days. This could be done using a GPS reference signal or using Spectrum Lab. It is the latter that I shall be trying - receiving a VLF MSK signal on one antenna as the reference, then using SL to synthesise the continous TX carrier which is transmitted on a second antenna.

In reality to get 32km on VLF with my set-up was always a "long shot", but all parties agreed it was worth trying and we have all learned a lot in the process. Experimentation is the name of the game and failure is as important as success.

It may be some time before I try the long range VLF tests again: I hope to have over 100W next time and a super-stable TX signal. Who knows, we might just succeed next time.

For information on these software packages (all free) that I use at VLF see https://sites.google.com/site/sub9khz/software .

My 10m halo - soon time for an overhaul

After the CQWW DX contest this weekend I plan to take down my Homebase-10 halo and rebuild it. The birds have managed to tear away at  the nylon rope supporting the nested 6m halo and the wooden supports now look a bit weather beaten.

So, I plan to replace the wooden cross frame supports with PVC pipe or fibre glass rods and re-do the wire elements. These have been up in all weathers for around 4 years now, so a few pounds on a remake is justified. The antenna works so well and is so small that I cannot think of a better antenna for the 10m band short of going to a beam which would be huge by comparison and need a rotator. The neighbours are quite used to it too, which is good.

Ten-Tec Argonaut VI latest

Ten-Tec is working on a new Argonaut transceiver called the Argonaut VI.  Details remain sketchy but at K4SWL's website http://qrper.com/tag/model-539/ there is some news that 25 units are going through a pilot run currently with production likely towards the end of the year.

A photo of the Argonaut VI on the K4SWL website (linked)

There are not enough details available to make any judgement on this new QRP transceiver. As far as I can find there is nothing at all about it on the Ten-Tec website. Some rumours are that it will NOT cover 12m and 6m and neither will it support 10m FM. Who would produce a brand new HF radio without at least all 80-10m inclusive bands and modes?

Unless the price is very attractive and the unique features substantial, then I just cannot see it competing well against the 11 year old FT817 and the new Elecraft KX3. The pictures seen so far show a simple looking radio, some would say plain, but with what is supposed to be a very decent receiver along the lines of the Ten-Tec Eagle.

What's cooking Ten-Tec? Are you still going ahead with this transceiver? If so, please can we have some firmed-up specs and prices?

CQWW DX SSB contest this weekend

Although not a serious HF contester - I have never submitted a log -  I do enjoy a fling in the CQWW DX SSB contest at the end of October each year, usually on 28MHz.

The most I can run is 5W pep but, if conditions hold up, there should be little problem in working stacks of US and Canadian stations as well as loads of others worldwide.  This year I have a speech processor which appears to make a good 1-2 S-points difference and makes working DX much easier.

Especially towards the end of the contest there are plenty of big contest stations looking for new contacts. If you want to work some good DX plus new US states and Canadian provinces, then this coming weekend will be your best chance.  In my experience running QRP SSB is no barrier at all to working LOTS of DX in this contest.

Some people love contests on HF and VHF and others hate them. Personally, I am happy to enjoy the DX opportunities they provide and tolerate the heavy band usage they bring, albeit for 48 hours in the case of the CQWW.

CQ zones map

Exchange is report and CQ zone. In the UK we are zone 14, so a typical report would be "5914"

Low cost weak signal work from VLF to light

Well, I do get about a bit - in the spectrum that is!

1. At the moment I am running a test transmission on 8.977188kHz (precisely) to G3WCD who is trying to detect my VLF beacon in a 22uHz (yes micro-Hertz) bandwidth over several days. Chris is 32km away.
2. I am running WSPR on 28MHz with 200mW and, for the second day running, my QRP signals have reached Australia.
3. In 2 weeks time (when the grandchildren have gone home) I will be resuming my over-the-horizon QRSS tests on 481THz (red light) using my high power beacon and more sensitive detector. The signal is too weak to see by eye, yet the sensitive kit can detect it.

All three of these have one thing in common: the circuitry to do them all is very very simple and the kit cost just a few pounds to build.

Over-the-horizon 481THz optical signal from G4HJW last winter

In each case though the processing power of a PC is used to help extract weak signals from deep in the noise. Luckily the software in each case is absolutely free: Spectran and Spectrum Lab for VLF and optical frequency detection and WSPR software for the WSPR tests.

Homebase-10 28MHz wire halo antenna

Homebase-10 antenna on the back of my house.

28MHz (10m) is excellent at the moment. If you are looking for a small, simple, horizontally polarised, omni-directional antenna for 28MHz, you may want to build a copy of my Homebase-10 halo which was published in Practical Wireless a few years ago. This antenna takes hardly any space, is simple and inexpensive to make and works extremely well. All the parts apart from the wire can be obtained from your local hardware store (wood, brackets, screws etc). You should easily have change from a £10 note.

The results on WSPR today (see previous post) give some indication of how well it performs. Mine currently has a second halo nested inside the first giving me coverage on 50MHz too.

WISPY spans the globe

Today WISPY, my little 10m 200mW WSPR beacon, excelled itself getting spots from 5 continents with the best being a spot from Australia late this morning. 

Conditions in the last few days have been excellent. I keep reminding myself that if, as some are now saying, cycle 24 has already peaked and we are on the way down, conditions in my lifetime (and probably most of those reading this) are unlikely EVER to be as good again.  It is just possible there may be a second peak next year which is stronger, but I somehow doubt this now.

Unique 10m WSPR reports with 200mW and a halo today

10m QRP (2W) AM DX QSO

The excellent conditions on HF today

Just worked K1IED in Connecticut when using 2W AM to my halo antenna. The 10m AM segment is busy with some good signals from the US and Canada. When 10m AM is like this you just know 10m is wide open.

Although K1KW was an excellent AM signal I was unable to get through the pileup on AM to work him.

The very poor quality video below shows K1IED's 10m AM signal a few minutes after I worked him.

Simple 10m AM transceiver?

Yesterday, someone suggested that I build a simple 10m AM rig. Now clearly the best option would be a DSB transceiver for which I have many of the ideas clear in my head and implemented in my WISPY transceiver for WSPR.

However, I think it would be fun to make a 10m version of my Fredbox and Sixbox QRP AM transceivers. These are to be described in an article in Practical Wireless. For local nattering I think more output is needed on 10m, probably 1-2W AM. A low level series modulator followed by a single stage linear amplifier is a simple way to go on TX. For receive, a super-regen receiver would be fine for local use when the band is not busy. This is 75% of the time at least and almost 100% of the time in the evenings, most times of the year. It would be unsuitable when the band is very active, as currently during the day. A better AM receiver could be built, but nothing beats a super-regen for elegant simplicity, as long as it has an RF amp to isolate it from the antenna.

Maybe this is a quick project for a few autumn afternoons. A few watts of AM on 10m should span several miles locally with a vertical or a dipole.