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.

472kHz Transverter Updated

A few people have now successfully copied the transverter design. I have just updated the webpage describing it and corrected a few errors on the schematic. Also, I have shown an additional low pass filter on the output which is prudent. It should not be necessary with a sharply tuned short Marconi or loop antenna.

See https://sites.google.com/site/g3xbmqrp/Home/472khz-transverter for the updates.

Rev H 472/500kHz Transverter Schematic (click to enlarge)

Petrol from air and water???

The BBC Business page carried a story this week about a company in NE England that is developing a technique to produce petrol from air and water. This sounds like something too good to be true, but if scaled up to production levels could be something remarkable.

"A British firm based on Teesside says it's designed revolutionary new technology that can produce petrol using air and water. Air Fuel Synthesis in Stockton-on-Tees has produced five litres of petrol since August, but hopes to be in production by 2015 making synthetic fuel targeted at the motor sports sector. The company believes the technique could help solve energy supply problems and curb global warming."

See http://www.bbc.co.uk/news/business-20003704 .