Optical comms at 481THz

It is some years since I last tried optical communications. This has been because of my poor health. 481THz is easy: all gear was home made and test gear is simple. In most ways nanowaves are easier than microwaves. My "speciality" was non line of sight (NLOS) using digital techniques. I also had one 2-way optical QSO over about 11km. Then I had a stroke and everything stopped!

My experiments used low cost red LEDs. At some point I'd like to try infrared. My tripod was low cost. A better one is really needed as aiming is important.

See https://sites.google.com/site/g3xbmqrp3/optical .

10GHz contest and 1296MHz operation

Sadly, I have no gear for 10GHz. I think there was a 10GHz contest on Sunday afternoon. I have thought about getting something, also for 1296MHz /P. If I was fitter I might have got "my arse into gear" sooner. As it is, I guess one can only do so much in our great hobby, especially if fitness is a thing of the past!

There is a quite low cost 1296MHz 2W transverter available from Bulgaria (SG lab) which has had good reviews. I know G8LRD (David) uses one with his FT817 when out portable and works some decent ranges. I cannot remember what antenna he uses.

The image is from the SG Labs website. I hope they don't mind me linking to it.

As you can see, this is small and light enough to be mounted on a portable mast close to a 23cm antenna to minimise cable losses.

As I could not find a price for this transverter on their website, I dropped them an email. I got a reply very quickly: 156 euros plus 8 euros economy shipping to the UK. They accept PayPal. Not bad for a 2W, sensitive, transverter. This is for V2.3 which also accepts an external 10MHz reference.

See http://www.sg-lab.com/TR1300/tr1300.html

DX via noctilucent clouds?

These high altitude clouds appear most often around the summer solstice and support radar returns. It has yet to be tried, but it means very long distance UHF, SHF and microwave paths may be possible using these clouds. Who will try?

See https://sites.google.com/site/g3xbmqrp3/vuhf/noctilucent .

An effective 10m antenna

At the old QTH (we moved a few years ago) I used my Homebase-10 antenna for 10m. As we enter the Es season when 10m springs to life with loads of Europeans, perhaps it is worth reminding readers of this low cost antenna.

It is basically a wire halo, small, and pretty omni-directional. It can be made with low cost materials, most of which you can buy at your local hardware store. In its time it has enabled me to work all over the world with QRP. It was in Practical Wireless in 2008 and is on my www.g3xbm.co.uk main site.

Despite my poor health, maybe I should try to get one up again at this QTH? I think I could make it (although not as easy as in the past) but I'd need help to get it up in place of my big-wheel. I think I could use the same small support mast. I'd probably feed it with some new RG58 coax.

See https://sites.google.com/site/g3xbmqrp3/antennas/homebase

4m in the USA

Although the prospects of an amateur 4m band in the USA remains a distant dream - the FCC seem very very slow allocating 137kHz and 472kHz - Southgate News reports that the 3kW ERP 4m beacon in the USA, in FM07 square, has been granted clearance to continue for another 2 years. 6m openings to the USA occur by Es most summers, but 4m is much harder. This is a useful propagation indicator.

See http://southgatearc.org/news/2017/march/4-metres-and-wg2xpn.htm#.WLgpUoXXJMs

4m is a band I have hardly tried. I do recall working ZB2VHF with a few watts of AM by Es back in my university days as G3OUL from Liverpool - 1969? These days there are lots of European countries on the band and I would think it a decent band for inter-G QSOs. I recall doing one 4m contest in my early days at Pye Telecom. It was April 1971 and we were in the back of a Land Rover. It was freezing! We used a converted Pye AM Cambridge and a 3 el I seem to recall.

Amateur radio below 9kHz

Until a few years ago, the conventional wisdom was that you needed huge power and huge antennas to be copied "beyond the garden fence" at VLF and ULF. In recent years much has changed and time and again great distances have been covered by amateurs with quite low power and modest antennas.

The trick is great stability, very narrow bandwidths and long integration times, often of days. For several years just detecting a carrier was enough, but in recent times people have been sending simple messages using EbNaut software.

When at the old QTH I detected signals from several European countries using simple, homemade gear and free software.

Although not totally up to date at all times, I try to update news of amateur VLF and ULF experiments at https://sites.google.com/site/sub9khz/ .

Geosynchronous amateur satellite delay

A few weeks ago, sorry I cannot remember where, I read that the Qatar amateur satellite, due to be placed in a geosynchronous orbit, has been delayed by a year. This means its launch is now due in 2018 and not this spring.

As the solar activity is likely to be low for a long time, a geosynchronous amateur transponder could be very useful. I certainly hope it is successfully launched in 2018.

The satellite I am thinking about was to have been a Middle-East one with coverage of Europe, Asia and Africa. A separate design covering the USA and just some of Europe was announced by AMSAT-NA last year.

UPDATE 1042z: See https://amsat-uk.org/2014/09/21/eshail-2-ham-radio-transponders/ and https://www.eshailsat.qa/ and https://www.eshailsat.qa/en/satellites .

472kHz WSPR RX

After a fair break, I am looking on 472kHz WSPR RX. For some reason, my TX antenna current reading is about a third of what it should be, so I am just RX for now until I can investigate further. The earth-electrode "antenna" is still being used.

Initial 472kHz WSPR spots

10GHz made simple

The HB100 Doppler radar modules can be bought for just a few UK pounds on eBay. These are the modern day equivalent of the Gunnplexers of old. A range of 161km has been achieved with one of these at the focus of a dish antenna on wideband FM.

In conjunction with a separate LNB converting down to 600MHz and a wideband FM RX and you have the makings of a low cost 10GHz system. This was recently used by G4HJW to cover a 10km path. I think Bernie was using just the HB100's own antenna. The HB100 is basically a small PCB unit.

At least one UK station is trying to design a stand-alone 10GHz transceiver based on the HB100 module. Watch this space!

Simple 10GHz

Yesterday I received this, which may interest those setting out on 10GHz:

Hi Roger,

We report our experience with HB100 module.

Please visit the Facebook page "HB100 10GHz"

https://www.facebook.com/groups/603514236508122/?ref=ts&fref=ts

Thank's

73, Nino IZ8WLZ

Amateur Radio Blog

This is always worth a look as there is usually something of interest.

See http://www.amateurradio.com/ .

WSPR on PSK Reporter Maps

This is something I have not used. Apparently PSK Reporter Maps can be used to plot WSPR spots. PSK Reporter can, in fact, be used with very many modes. I use it for JT65 but I may try ISCSAT on 2m tonight sending a beacon message like "B G3XBM JO02" if this is supported.

Not a bad session on 472kHz WSPR

Overnight, I was spotted in 5 countries by 11 unique stations on 472kHz WSPR. As usual, I get a measured 5mW ERP on TX from my earth-electrode "antenna". The power from the transverter is about 12W into 50 ohms.

Just about anyone could get on this band with WSPR with a similar set-up. Big antennas and great earth systems are nice, but are not a prerequisite to get started on the band.

472kHz homebrew transverter

Uniques on 472kHz WSPR overnight on TX (5mW ERP)

First sunspot of cycle 25 spotted

Now, please don't get excited as the peak (such as it will be) is years and years away but there are reports of the first sunspot of the new cycle spotted. This has a different polarity to those of cycle 24.

See http://qrznow.com/fast-solar-solar-wind-first-sunspot-of-a-new-cycle/?utm_source=dlvr.it&utm_medium=twitter

EME

Moonbounce (EME) impresses me as I know some work really hard to optimise their stations to achieve this most difficult aspect of our hobby. In recent years it has become a little easier (although still hard) with the advent of digital modes optimised for EME paths.

Jan, LA3EQ posted a video on YouTube showing his SSB reception of HB9Q via the moon. Amazing!

Earth-electrode antennas at 472kHz

Some 4 years ago I posted this based on my results at 472kHz:

These were my conclusions in Jan 2013:

1. The earth-electrode antenna at 472kHz (2 earth rods in the soil 15-20m apart fed from the TX output) behaves like an H-field loop transmitting antenna. At the present QTH the spacing is less.
2. It has directivity, with strongest signals in the line of the loop and weakest signals at right angles to it.
3. It works as an effective RX antenna too.
4. In my environment the loop looks like about 50-60 ohms resistive, so a good match to my transverter directly without matching. At this QTH it looks a higher impedance, presumably because the soil and rock are different.
5. The structure works because much of the return current flows deep within the soil and rock beneath the earth-electrode antenna. In my case Rik OR7T calculated that the loop area in the ground is effectively 290m sq with a radiation resistance of 0.017 ohm and a loss resistance of 66 ohms.This is a BIG loop! I think the loop is smaller at this QTH.
6. Performance compared with my 9m high top loaded Marconi antenna averages only around 8dB down, not a bad figure at all, even with the connecting wire on the ground and not elevated at all.
7. Where no other antenna option is available, the earth-electrode antenna is well worth trying both on 472kHz and on 136kHz both for RX and TX. Although it works well here, your geology may be different and results not the same.

472kHz WSPR analysis by PA1B

Bert, PA1B, has done some analysis of my 472kHz WSPR to see how little power (ERP) would be needed to be still copied. Of course, this assumes reception is not external noise limited.

Lightwave Comms

Because of my poor health I have not been able to pursue 481THz (lightwave) experiments especially "over the horizon" NLOS tests. Thankfully, others are "carrying the torch" .

See http://qsl.net/ve7sl/westcoast%20lightwave%20project.pdf

Crystal Sets

It is some years since I last made a crystal set, but I well recall a UK book called "The Boy's Book of Crystal Sets" which I think was first published in 1954. It is available on-line.  At the time "Boy's" was OK. If published now, we'd have to say "Young Person's".

Years back I made a short-wave crystal set and heard some impressive DX with it including Radio Australia and Radio Havana. Both these and many others were NOT more local relays. Radio Australia was a real catch and totally amazed me at the time.

See http://www.vintageradio.me.uk/crystal/boys_book_xtal.htm .

There is also some information on my main website. Crystal sets are easy to make and capable of surprising results.

See https://sites.google.com/site/g3xbmqrp3/hf/crystalset .

AmateurRadio.com website

See http://www.amateurradio.com/ .

There is usually something of interest on this site.