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

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

6m MSK144 RX evening and overnight

As the DX on 10m seems to have stopped some hours ago, I QSYed to 6m MSK144 RX. So far I have only spotted PA5Y (384km). I assume this was by aircraft reflection.

Overnight I expect to remain on 6m MSK144 RX.

UPDATE 2200z: OZ1PIF (850km) has just been spotted on 6m MSK144.

Given up on 10m?

It would appear that most have given up on 10m and migrated to lower frequencies where there are easier pickings. Understandable, but a shame as it means there are now far fewer people around to catch the openings that still do occur on 10m.

For a long time I have recommended digital modes like WSPR or JT65 running in the background. Only low power is needed.  WSPR creates its own beaconing format, but sending "B callsign locator" in JT65 appears on PSK Reporter Maps, so you can soon see where your JT65 signal is being copied. Yes, 10m DX is still there, but harder to find now than a few years ago.

But, are you man enough to take the 10m challenge?

I have said before, but if all you want to do is chat to friends around the world you can do this by video for nothing on the internet. Amateur radio is about learning and pushing the boundaries. For many years 10m will be that final HF frontier.

Care to join us?

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

Simple yagi for wi-fi router

This was first seen some weeks ago and I saw it earlier today in an email from Twitter. It shows you how to make a simple add-on yagi for your wi-fi router.

In my case I get sufficient range with the router "as is". You might find it useful if you need to increase the range in a certain direction. It is a simple idea, which I like.

See https://hackaday.com/2017/01/24/a-simple-yagi-antenna-for-your-wi-fi-router/ .

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

SAQ (17.2kHz) VLF

Southgate News reports that there was a successful transmission this last Christmas. There was some doubt due to a fire earlier in the year. I did not try to copy them this year. My VLF converter may be used to copy them. I have a QSL card from them from years ago.

See http://alexander.n.se/wp-content/uploads/2017/01/SUMMARY-REPORT-ON-SAQ-TRANSMISSION-CHRISTMAS-2016-12-24-1.pdf for a summary report.

See also https://sites.google.com/site/sm6lkm/saqrx/ for a very good software RX. On my You Tube channel (G3XBM) there is a video of this in use.

Other bands WSPR or JT65?

As I am unlikely to be able to erect a better MF antenna before next autumn, I wonder what band I should use overnight on WSPR or JT65? 5MHz (60m) I can manage as I've resonated the antenna before. My noise floor is bad on 5MHz, but I should be able to TX (beacon) with either WSPR or JT65. I know 40m or 30m are possible (but little challenge), but in "quiet sun" years 5MHz (60m) is likely to be "open" more.

I may give 5MHz a go tonight. I have still to decide WSPR or JT65. As usual, I'd use 2W.

UPDATE 2008z:  I could not load my antenna up on 60m, so  have gone on 40m WSPR this evening and overnight.

40m WSPR spots this evening

UPDATE 2230z: Most spots of my 40m WSPR (2W) are from Germany. Best DX on TX was SA6BSS/RX (1059km). My antenna is far from ideal on 40m. It is very low.

Tests at even lower frequencies

DK7FC has been testing at even lower frequencies:

Hi ULF,

Since a few hours i'm running 15 mA antenna current on 970 Hz, the 309 km band. This requires to apply 5 kV to the antenna. You can see a very faint trace on the lower image at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html

Just about 10 dB SNR in 424 uHz in 3.5 km distance, or in 0.011 lambda distance. The receive antenna is a H field antenna that is not even pointing to the transmitter. Also the preamp noise is dominating the background noise on that frequency. So the RX is deaf on that band. Anyway, there is something.

The ALC into SpecLab does a very good job, it holds the antenna current stable during all the changes and working point drifts. The plot can be seen at http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/TX.png
15 mA results in an ERP of  3 nW.

My new preamp circuit is waiting for a first test together with the large loop. I hope to pick up the signal in at least 5 km distance with that preamp which is really low noise down to the lower Hz range.
An E field reeiver would be a better choise for the reception from that E field Tx antenna, at least in the lower near field. Maybe that will give another test then.

With 30 kV i could reach 0.3 uW. Not sure where this could be detected? And who knows the advantages of this part of the spectrum for our purposes!?!

Since 21:20 UTC, a 2 character EbNaut message is running. It will take 2h, 2min, 40s. Hopefully the tree grabber is available until the message ends. It will shut down in a few hours due to lack of solar energy in these days (an improvement of this system has already been prepared and waits for the installation).


73, Stefan

Sunspots and 10m - Tuesday January 10th 2016

Solar flux remains at 72 and yet again the sun is spotless. A=12 and K=2. We are now definitely entering "quiet sun" times and these could last for many years. Es may liven 10m a bit.

Even in very quiet years there can be some N-S F layer DX on 10m. JT65 or WSPR should be ideal modes as long as people stick with the band. All too often, people go on SSB, see no activity, then go down to a band where there is more activity. Meanwhile, 10m is open and the DX gets missed.

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.

Return to 10m JT65

After an evening and overnight on 630m WSPR (best DX with 5mW ERP was F1AFJ/1 at 607km), I returned to 10m JT65 just before breakfast. No spots yet on 10m JT65.

UPDATE 1248z: G4CJC (73km) spotted by tropo or aircraft on 10m JT65. DL0ZB (601km) copied by 10m Es I assume.

Microwave TX and RX modules

I have just seen this site, although I have never used it so cannot say how good the service is.

See http://www.13cm.co.uk/index.php

German Callbook

My friend Steve G1KQH has sent me a link to the German Callbook. I am unlikely to use it, but the link is attached in case you need it.

See https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Rufzeichenliste/Rufzeichenliste_AFU.pdf?__blob=publicationFile&v=24

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.

Early lightbeam tests

Waverley Rd, Kingsbridge, Devon, UK

My interest in light-beam communication goes right back to the 1960s when an old school friend and I used a torch bulb as the TX and an OC71 transistor with the black paint scraped off as the RX detector.

One of our first tests was across the street shown in this photo. I lived in the first house on the RHS and we received the test in the house with bay windows on the left. DX was about 25m! We AM modulated the torch bulb biasing it at half rail if memory serves me correctly. It had a very low frequency response as the torch bulb had a poor HF response, as I recall.

We moved to this house in 1959 but the photo is years and years earlier.