Friday, 17 December 2010

HF Propagation – December/January


G0KYA's propagation charts from UK for January 2011

This is the period when the low bands (160m, 80m and 40m) come into their own. The last two winters have seen great low-band propagation, with stations in the USA and Caribbean being worked on 80m well after sunrise. If you do nothing else keep an eye on 160m, 80m and 40m this winter as the relatively low levels of solar activity, the long winter nights and low D layer absorption means that DX may be heard all night long.

Band by band:

On 160m (1.8MHz or Top Band), solar absorption will prevent skip during the daylight hours. You should be able to work other UK stations out to about 50-80 miles via ground wave. The band will open around sunset and openings up to around 1,300 miles should be possible, with frequent openings up 2,300 miles. DX openings to the east from the UK should be possible around midnight and to the west before sunrise for well-equipped stations.

On 80m (3.5MHz), expect a similar pattern to Top Band with DX openings at night with peaks at midnight and around sunrise (greyline openings). Openings around the UK and out to around 500 miles should be possible during the day and between 750-2,300 miles at night. A low, horizontal antenna will be useful for relatively local, NVIS (Near Vertical Incidence Skywave) signals, but lower angle radiation, such as obtained with a vertical, will be required for DX.

Listen for DX from the West just before and just after sunrise – these are the months you are likely to hear US stations around 3795MHz in the morning.

40m (7MHz) is also another great DX band at this time of year. Forty metres should open to DX is an easterly direction during the late afternoon and towards the south at sunset. Paths during the afternoon may also include W6 (west coast USA) in mid winter. Openings to the west, including long path to VK/ZL should be possible after midnight and should peak just before sunrise. Relatively local contacts should be possible during the day, although low critical frequencies will mean that it is difficult to work other UK stations while perfectly possible to talk to European stations.

20m (14MHz) is likely to provide great DX openings during the hours of daylight. Peak conditions will be a couple of hours after sunrise for paths to the east and a couple of hours before sunset for paths to the west. Contacts up to 2,300 miles should be possible during daylight hours, but the band is likely to close to DX an hour or so after sunset. Occasional DX openings towards South America may be possible after nightfall.

17m/15m (18MHz/21MHz) should provide fairly good DX openings during daylight hours, although 15m may struggle to open at all on some days if the flux doesn’t rise above 80-90. The period from noon to late afternoon may be best, but both bands are likely to close at sunset and remain closed until some time after sunrise the following day.

12m/10m (24MHz/28MHz) may be good or bad depending on how the solar cycle progresses. If the flux stays in the 70s-80s there may be many days where there are no signals at all, although occasional brief openings to DX may be possible. If the solar flux heads towards the high 90s or more than 100 then good DX should be possible during daylight. A brief spell of sporadic-E can sometimes occur in the New Year resulting in very strong, but short-lived propagation on 10m out to around 1,300 miles.

A quick tip – if 28MHz seems dead listen to 27.555MHz USB which is a CB calling frequency. Activity there usually means that 10m may open up shortly after.

Stealth Antennas - now available in USA


My RSGB book "Stealth Antennas" is now available in the USA from the ARRL.

Tiny postage stamp-size gardens, intolerant neighbours, planning permission problems, living in apartments: these are some of the challenges facing the modern radio amateur when trying to get on the air. Stealth Antennas offers clear practical advice to those who might have thought they were unable to put up a suitable antenna.

You can buy it in Europe from the RSGB and in the USA from ARRL.

I'd like to take this opportunity to thank the many US hams who helped with the book by contributing their stories.

Wednesday, 17 November 2010

The EFHW - an efficient monoband end-fed half wave for 10m, 20m or any other HF band


Update: A detailed description and construction details are now available for download (PDF).

I like half wave dipoles. They are easy to make and easy to set up. They also perform very well and usually beat a compromise antenna hands down. With 10m about to come alive again as solar cycle 24 gets going what I wanted was a low-angle efficient radiator that could be put up and down in a couple of minutes.

My experience with ground plane verticals has been OK, but they are only as good as the earth beneath them. That is, they really need an extensive array of ground radials to work properly – not easy to put down when you are in a hurry.
I also like to use fibreglass fishing poles as antenna supports. These are available cheaply (I have a 7m version and a 10m version that I bought from Sandpiper at the Leicester rally). The only problem is that they don’t have lateral strength – they are good for supporting verticals, but not so good for half-wave horizontal dipoles.
What I really wanted to do was have a vertical half wave dipole, but the problem is that while the impedance at the centre of a dipole is about 50-75 Ohms, and very easy to match to coax, an end-fed half-wave has a very high impedance indeed, around 3000-4000 Ohms. If you just connect it to your coax or rig you will be disappointed.
Enter the End fed Half Wave as featured in my "Stealth Antennas" book - download the PDF for full details.
Update: now includes full construction details to download (PDF).

Sunday, 14 November 2010

NDBs (Non Directional Beacons) in the UK


If you fancy a bit of LF DXing, these frequencies might be worth a try. They are non-directional beacons and are used by aircraft. I searched high and low until I found this list, so thought I would share it. Some may now be off the air.

I can hear my local NWI (Norwich) beacon but that's it. They send their idents in fairly slow Morse code. Have a listen, especially at night

Download the UK NDB list (PDF)

Tuesday, 9 November 2010

Understanding LF and HF Propagation ebook


In 2008/2009 Alan Melia G3NYK and I wrote a series of features on understanding LF and HF propagation for the Radio Society of Great Britain's (RSGB) "RadCom" magazine.

My features consisted of a month-by-month look at each HF band in turn, showing the reader the propagation modes behind each band and explaining some of the technicalities of ionospheric propagation.

I looked at the D, E and F layers, Sporadic E, the MUF/LUF, using solar data, propagation programs, NVIS and much more.

Alan then took over and wrote three detailed features on LF propagation. We are told that the features were well received and as a result I have managed to persuade the RSGB to allow me to put them together into a single document, which is now freely available for amateurs worldwide to download.

I hope you enjoy it.

Steve G0KYA

Download the "Understanding LF and HF Propagation" PDF (1mb)

Wednesday, 13 October 2010

More on the 20m EH antenna


I recently attended a lecture on small antennas at the RSGB convention by Professor Mike Underhill G3LHZ (pictured on the right with me). Mike asked me to take my 20m EH antenna along (which has been featured on this blog) so that he could take some measurements with his miniVNA.

I set it up on a tripod in the seminar room and hooked it up to my Yaesu FT-817. What surprised me (and the delegates) was the fact that it was receiving signals from around Europe at up to S9 +20dB.

OK, a dipole could have done the same, but for a four foot antenna mounted on a tripod indoors that's pretty good. The antenna was built for my RSGB "Stealth Antennas" book (available now from RSGB and on their website soon) and has now been put back in my loft, where it happily offers a 1.4:1 SWR and signals that get close to my other antennas, sometimes beating them.

Say that it works by Poynting Vector Synthesis (PVS) and the experts go mad. But think of it as a short, fat dipole with a matching network and it still does the same job and everyone is happy ;-)

As one delegate said: "My friend lives in a flat and would love one of these".

Click on my link to read more
or see http://groups.yahoo.com/group/eh-antenna/

UPDATE: "Stealth Antennas" now for sale on RSGB website.

Monday, 11 October 2010

Podcast: HF Propagation Report, October 2010


A change to the usual format this month. This Podcast features interviews with Dr Lucie Green, a solar physicist, who talks about her work on coronal mass ejections, and with Carl Luetzelschwab K9LA about what drives Top Band propagation and what to look for on 160m this winter.

Click on the headline to listen to the programme online or if you prefer to listen to it on your iPod search for G0KYA on iTunes.

Tuesday, 5 October 2010

HF Propagation Predictions, October 2010


Note: You can find HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/

Solar conditions improved over the last month. As I write this on 5 October the solar flux is 76, but it did touch 91 during the last 30 days.

HF conditions have improved dramatically, but this is mainly due to the seasonal change. If you haven’t been on HF for the last few months get on now!

Openings have included 10m paths to Malaysia and VK, although I couldn’t hear them.

21MHz (15m) is opening up reliably – the US is easily workable at times. I worked W8FHF in Ohio using 100W to a long wire laying on the roof – he was stronger on that antenna than any of the others.

7MHz (40m) is also showing great promise. You can hear the US in the evening quite well and morning openings to VK are possible. Gerry VK7GK in Tasmania was 59 on 7.160MHz the other morning (long path) and gave me 57 on the Windom.

October also brings CQWW which always brings out the DX, so get on the bands.

Now lets look at the rest:

The equinox periods provide longer daytime periods than winter, but logically, shorter night-time periods too. These tend to be the best months for working North-South paths, such as UK to South Africa and South America.

On 160m (1.8MHz or Top Band), look for short-skip and DX openings at night. Again, no daylight skip is possible due to absorption, but openings out to 1,300 miles and occasionally further afield can be expected at night with conditions peaking around midnight and again at sunrise (greyline).

80m (3.5MHz) will generally follow the characteristics of Top Band at night, but will also provide good openings out to around 250 miles during the day. These will lengthen to around 500-2,300 miles at night with fairly good DX opportunities at times. At this point in the cycle 80m should still provide good DX as absorption is still quite low.

40m (7MHz) Forty metres should open to DX in an easterly direction at sunset. Openings to the west should be possible after midnight and should peak just before sunrise. Contacts should be possible during the day, although, again, lower critical frequencies may mean that it is difficult to work other UK stations while perfectly possible to talk to European stations. If the flux rises then 40m may open up to NVIS contacts around the UK. Look out for long path openings to VK/ZL in the morning too.

20m (14MHz) is likely to be the best DX band between sunrise and sunset. The bands may occasionally open after dark, perhaps to the south west form the UK. Good openings will be possible during daylight hours out to around 2,300 miles.

17m/15m (18MHz/21MHz) should provide fairly good DX openings during daylight hours, especially to Africa and South America, with 17m being open more often than 15m. Once again, 15m may struggle to open during times of low solar flux, but could provide good openings if it rises above about 80-90. Be prepared for some surprises though as this is a good month for 15m. Both bands are likely to close after sunset towards the end of the month, although do check for openings after dark as they can occur.

12m/10m (24MHz/28MHz) These could be disappointing bands if the solar flux remains low. If the solar flux heads towards the high 80s/90s then openings will occur on both bands, although 24MHz will open first. If it breaks the 100 mark then expect to see some good DX openings on 10m, especially in late autumn.

You can find HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/


You can also listen to Steve G0KYA's HF propagation podcast on iTunes or at http://www.g0kya.blogspot.com/

Steve G0KYA
RSGB Propagation Studies Committee

Friday, 1 October 2010

New stealth antenna book released



I’m pleased to announce that my new book “Stealth Antennas” was launched at the Newark Hamfest in the UK. The book is now available to buy from the RSGB .

It will also be available from the ARRL in due course.

It looks at a host of stealth antennas, including indoor dipoles, magnetic loops, stealth verticals, flagpoles, birdhouses and others. It also looks at more esoteric designs like the EH, Microverts, microloops, Isotrons, plus lots of case studies from around the world.

There are details on safety, minimising RFI, ununs, baluns, EFHW matching, the Rybakov – even a zig-zag portable dipole that fits in a folder.

Keep an eye open for it at rallies too.

UPDATE: Now for sale on the RSGB website.

Steve G0KYA

Wednesday, 29 September 2010

Propagation talk at Newark Hamfest, Oct 2010


I will be giving a talk on HF propagation and prediction programs at the Newark Hamfest on Friday 1st October. I've made the presentation available as PDF file so that anyone who attends can download it. It may not make as much sense as it will with my commentary, but there is some useful info there. It is about 7Mb.

Click to download the presentation
.

Friday, 17 September 2010

History of ships' radio room clocks


Remember when all ships had real radio operators? If you do you'll know that the ops had to maintain "silent periods" when they wouldn't transmit, instead listening for distress calls on 500kHz and 2182kHz. For this they had a special radio room clock with sectors marked on it.

After the loss of the Titanic, the radio frequency of 500 kHz became an international calling and distress frequency for Morse code maritime communication. For most of its history, the international distress frequency was referred to by its equivalent wavelength, 600 meters, or, using the earlier frequency unit name, 500 kilocycles [per second] or 500 kc.

2182kHz was added later and transmissions on 2182 kHz commonly use single-sideband modulation (SSB) (upper sideband only). However, amplitude modulation (AM) was often used in some parts of the world.

Maritime coastal stations used to maintain 24 hour watches on these frequencies, staffed by highly-skilled radio operators.

As a reminder, a ship's radio room clock would have the 500kHz silence periods marked by shading the sectors between h+15 to h+18 and h+45 to h+48 in RED. Similar sectors between h+00 to H+03 and h+30 to h+33 were marked in GREEN, which is the corresponding silence period for 2182 kHz.

Anyone breaking the rules would soon hear "QRT SP" in Morse Code, meaning "STOP SENDING - SILENT PERIOD!"

I've always wanted to have one of these clocks for my own shack, but couldn't find one. So … I decided to make one. I spent two days with a graphics program recreating a radio room clock from the Winthrop Clock Company of Boston, Ma., USA. It wasn't easy, but I then took the finished result, printed it and pulled apart a quartz clock that I bought for the job and installed it - what a lot of work!

The end result is shown in the photograph above and creates quite a lot of attention in my shack. It also keeps time really well too!

There is even The Radio Maritime Day each April where you have to obey the silent periods, so it comes in useful

Anyway, after all that work it seemed a shame to waste the artwork. I then found that I could upload it to a company called CafePress, letting people buy their own clock. While I was there I also designed some T-shirts, mugs, mouse mats and other goodies.

These products, including a reproduction radio room clock, let you relive those bygone, halcyon days when "sparks" ruled the maritime airwaves. So your shack can now look like a ship's radio room!

If you are in the UK go to http://www.cafepress.co.uk/theradioroom or if elsewhere http://www.cafepress.com/theradioroom – you can select the currency you wish to pay with.

I have one of the new Cafe Press clocks - it is about 10 inches in diameter and very striking. It is quartz powered so keeps good time and the tick isn't too loud either. Looks very nice on the wall and not too expensive either.

But remember QRT SP!

Friday, 10 September 2010

Podcast: HF Propagation Report, September 2010


Report for September 2010 with a look at how solar cycle 24 still isn't going too well and why HF conditions will now start to improve in September and October. Just click on the Podcast headline above or search for G0KYA on iTunes.

Friday, 3 September 2010

HF Propagation, September 2010


Note: You can find Steve's HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/

Solar conditions still continue to be fairly poor. As I write this on 3 September there are sunspots, but the flux is stubbornly in the mid to high 70s. There have been auroral conditions over the past few days and we can expect to see more unsettled conditions as the cycle progresses.

Having said that, conditions are improving due to seasonal variations. We are heading away from the summer solstice and towards the equinox. The ionosphere is cooling down and its chemistry is changing. Traditionally late September and October are good times and we can expect to see increasing DX being worked.

In some respects this has already started to appear. There have been some good 20m openings from the UK to the West Coast of the USA and Alaska, plus openings to the Far East.

Given the lowish solar flux I think we will continue to see 20m (14MHz) and 17m (18MHz) as the “money bands”, but don't write off 15m (21MHz) which will open to DX, but perhaps not as often as the lower bands.

Late September will be the acid test – and with flux levels in the 70s we are unlikely to see many (any?) trans-Atlantic openings on 10m. Sorry - I would love to be proved wrong!

Now let's look at each band and what you can expect.

The equinox periods provide longer daytime periods than winter, but logically, shorter night-time periods too. These tend to be the best months for working North-South paths, such as UK to South Africa and South America.

On 160m (1.8MHz or Top Band), look for short-skip and DX openings at night. Again, no daylight skip is possible due to absorption, but openings out to 1,300 miles and occasionally further afield can be expected at night with conditions peaking around midnight and again at sunrise (greyline).

80m (3.5MHz) will generally follow the characteristics of Top Band at night, but will also provide good openings out to around 250 miles during the day. These will lengthen to around 500-2,300 miles at night with fairly good DX opportunities at times. At this point in the cycle 80m should still provide good DX around midnight as absorption is still quite low.

40m (7MHz) Forty metres should open to DX in an easterly direction at sunset. Openings to the west should be possible after midnight and should peak just before sunrise. Contacts should be possible during the day, although lower critical frequencies may mean that it is difficult to work other UK stations while perfectly possible to talk to European stations. If the flux rises then 40m may open up to NVIS contacts around the UK.

20m (14MHz) is likely to be the best DX band between sunrise and sunset. The bands may occasionally open after dark, perhaps to the southern hemisphere. Good openings will be possible during daylight hours out to around 2,300 miles.

17m/15m (18MHz/21MHz) should provide fairly good DX openings during daylight hours, especially to Africa and South America, with 17m being open more often than 15m. Once again, 15m may struggle to open during times of low solar flux, but could provide good openings if it rises above about 90-100. Both bands are likely to close after sunset, at least later in the month..

12m/10m (24MHz/28MHz) These could be disappointing bands if the solar flux remains low. If the solar flux heads towards the high 80s/90s then openings will occur on both bands, although 24MHz will open first. If it breaks the 100 mark then expect to see some good DX openings on 10m, especially in late autumn.

You can find HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/

You can also listen to Steve G0KYA's HF propagation podcast on iTunes or at http://www.g0kya.blogspot.com/

Steve G0KYA
RSGB Propagation Studies Committee

Thursday, 19 August 2010

The Western HF-10 multiband dipole


Latest News, 15-3-17: Fred is still making the antenna. He said: "Steve - I am still making the HF-10. I did stop for a while due to an illness. I don't sell them any more on Ebay. I can't keep up with demand. What I sell now comes through word of mouth. The price is £85 including special delivery."
You can contact Fred via m0bzi@outlook.com

The Western HF-10 multiband dipole was born out of Fred Western M0BZI's attempts at working 80m from a small garden. His basic design starting point was the half size G5RV, to which he added inductors on each leg. Unhappy with the results, he then played around with the overall length and added a balun at the feedpoint.

The end result is the antenna as now supplied.

Specifications
The Western HF-10 is a 67 feet long dipole/doublet. It incorporates two loading coils placed towards the end of the legs and has a 15 foot 3 inch section of 450 Ohm windowed ribbon feeder to the centre feed point. At the end of the 450 Ohm feeder a ferrite rod balun is fitted for the transition to 50 Ohm coax. This appears to be wound as a 4:1 impedance transformer.

The build quality is excellent and all fittings are stainless steel. The balun housing is substantial and all crimped joints are very strong and designed so that they don't stress the antenna.

The antenna wire is Flexweave, which is both strong and easy to work with.

Installation
For the test I installed the antenna an an inverted V with the apex at about 30ft and the ends at about 10 feet.

Out of the box the antenna was found to be resonant at 3.7MHz.
Initial SWR tests were done using a 15ft length of RG58 coax to an MFJ analyser. Subsequently, a further 60ft of RG213 was added to bring the end into the shack. The subsequent SWR readings with the additional length of coax are shown in brackets.

SWR measured with MFJ 269 antenna analyser at end of 15ft RG58 coax (and at end of 60ft RG213 coax)
1.9MHz: 31 (10.8:1)
3.5MHz: 3.7:1 (5.5:1)
3.7MHz: 1.2:1 (1:1) resonant point
3.8MHz: 4.3:1 (3.9:1)
7.0MHz: 6.2:1(3.3:1)
7.1MHz: 6.2:1 (3.3:1)
10.1MHz: 6.1:1 (3.2:1)
14MHz: 2.5:1 (1.6:1)
18.1MHz: 4.8:1 (2.7:1)
21MHz: 4.6:1 (2.3:1)
24.9MHz: 3.6:1(2.3:1)
28MHz: 1.2:1 (1.2:1)
29MHz: 1.9:1 (1.4:1)
50MHz 1.7:1 (1.5:1) – actually resonant at 48.6MHz

As can be seen, the SWR appears to go down once the additional coax is added. This is normal and is due to losses in the coax. Out of the box the antenna is naturally resonant on 80m, 20m and 10m.

The internal ATU on my Icom 756Pro 3 was able to find a 1:1 match on all bands 80m – 6m quite easily. Fred had said that his Yaesu FC-902 was also able to match the antenna on 160m, but the SWR was outside of the tuning range of my internal ATU.

Nevertheless, my external ATU was used to find a match on 160m, despite the antenna's short length.

First impressions
The antenna was mounted away from the house and fed via a 10 turn coax choke balun. This, plus the antenna's own balun resulted in a very quiet installation from a noise point of view.

With today's electrically noisy urban and suburban environments this was a breath of fresh air and made it that much easier to hear weak signals. The balanced design meant that there were NO detectable currents on the braid of the coax at all.

I had my doubts about the design of the antenna. It is very hard (if not impossible) to make a multi-band dipole that is coax fed and that will work on all bands. The Off Centre Fed Dipole (Windom or OCFD) is one design that gets close, but other designs (including the G5RV) fail to give a good match on all bands.

The problem is that they often display poor matches on many bands. The resultant poor SWR is often masked by coax losses on long runs, giving apparent better SWRs in the shack at the expense of losses in the coax caused by high SWR. This is why I did the initial SWR tests using a short length of coax.
Louis Varney G5RV himself also experimented with baluns at the open wire feeder/coax junction but abandoned the idea as the varying reactance at that point can lead to balun saturation and more losses/poor behaviour.

So I was interested to see how this model performed.

Performance
160m
I was able to tune the Western HF-10 on Top Band using an external ATU. The SWR is way too high for an internal ATU to match it on that band. Despite the antenna's short length I was able to work and hear UK stations, but signals were well down, typically around S5 compared with S9+10dB on my Windom (which itself is too short for Top Band). Nevertheless, if you only have room for a 67ft antenna it will let you experience the band. Noise levels were, once again, very low.

80m
The antenna's 80m performance was compared with an 85ft W3EDP and a 135ft home made OCFD (Windom) with a 4:1 balun, both with an apex at about 30 ft. I know exactly how these perform, having been using them in the RSGB's 80m Club Championship for three years. Best 80m DX on the OCFD has been VP8 Falkands and numerous US stations.

The antenna's noise level on 80m was found to be about three S points better than my existing antennas. This was because a) the Western HF-10 was situated further away from the house and b) it has an effective isolating balun. 

The offset nature of my OCFD means that it is prone to picking up noise on the feeder, despite a choke balun.

Signals from around the UK and Europe were generally found to be equal to or 1-2 S points down when received on the Western. This was to be expected as the antenna is only half the length of the Windom. The lower noise level however made it easier to hear people.

These results were fairly consistent – the difference was always between 0 and 10dB down. This isn't as bad as it sounds – signals that were S9 +20db on 80m might become S9 + 5-10dB. It was only very weak signals that were marginal. 

The low noise levels did make for easier listening though. I received a 59 +20db report from MJ0CTR in Jersey - what more could you ask for? At the time of testing (August) no 80m DX was heard.

40m (7MHz)
It was a similar story on 40m. EU signals were in general 1-2 S points down compared with the 136ft OCFD/85ft W3EDP, but lower noise levels made for easier listening. Some signals from DL were the same signal strength on all the antennas. Some were actually stronger on the Western.

30m (10MHz)
Again, lower noise was the order of the day. My OCFD is not really optimised for 30m and the Western outperformed it by up to 2 S points on CW around EU. A good antenna for this band. 
 
20m (14MHz)
Signal strengths from Europe were roughly equal to the other antennas. This was apparent on many signals and was not a one-off. Some signals were stronger on the Western by up to 2 S points. Tests with stations in VO1 and VE9 on 14MHz showed the antenna outperformed my existing antennas. This was the case too with a short skip contact with Jon GM3JIJ on the Isle of Lewis. This antenna really shines on 20m.
17m (18MHz)
Signals were once again roughly equal to my OCFD, but sometimes up to 2 S points weaker than on a dedicated 17m dipole. Noise levels were once again better. Switching between the two you could see the effects of polarisation shifting in the ionosphere as one and then the other antenna became louder.
15m (21MHz)
My Windom does not really work on 21MHz. I normally switch to the W3EDP or use a 40m dipole. The Western outperformed both.
12m, 10m, 6m (21MHz, 24MHz, 28MHz and 50 MHz)
I managed to find a few Es signals on 10m a few days after I wrote the original text. They were all down about 2-3 S points on the Western compared with a dipole and the Windom.

General Coverage
I couldn't help but try the antenna out on the Broadcast Shortwave/Medium Wave bands. It was capable of picking up BBC Radio Wales from Washford in Somerset on 882kHz in daylight hours ( I live in Norfolk), although my other antennas were louder. 
 
All of the stations I heard on the 7MHz, 9MHz, 11MHz, 15MHz were roughly all the same signal strength on both antennas. All India Radio on 6280kHz was down 20dB compared with my Windom.

Update: March 2014 
This review was written a couple of years ago. People have asked about the antenna's 60m (5MHz) performance. Although I didn't test it at the time the consensus from other people who have contacted me is that the antenna doesn't work well on this band.


Conclusions
I was very impressed with the Western HF-10. My first reaction was that it must be a bit of a compromise as it is only truly resonant on 80m. And yes, signal strengths were down a little overall. But the low noise characteristics of the antenna, and the fact that it could be persuaded to match on all bands 160 - 6m made it very usable.

On 20m the antenna matched or bettered my others in terms of performance, but with lower noise, which was a bonus.

You obviously trade off some performance on some bands compared with dedicated dipoles for each band, but this was never more than about 2 S points at worst (apart from Top Band). However, the low noise characteristics make up for this as I was often able to hear signals on the Western that were in the noise on my other antennas.

Given that these were also longer it shows how useful the Western HF-10 can be, especially if you do not have room for a full 80m antenna.

It also worked well on the shortwave broadcasts bands above about 4MHz.

For someone looking for an antenna that will fit in a small back garden, but will allow them to work all the HF bands, the Western HF-10 has a lot to offer.
Fred sells these antennas on Ebay or you can contact him via m0bzi@outlook.com

Tuesday, 13 July 2010

Night of nights, 13th July 2010


Every year maritime stations in the USA commemorate (not celebrate!) the closing down of the use of Morse code for maritime traffic. This happens on 12th July each year, going on to 13th July in Europe and eastward.

Known as "Night of Nights" stations like KPH and KSM in California, plus WLO in Alabama transmit on the HF maritime bands, and some, like K6KPH, transmit on the amateur bands.

Being stupid, I thought I would set my alarm for 5am on the morning of the 13th July and see if I could hear anything - I wasn't very confident.

VOAProp suggested that 8MHz offered the best shot and as it turned out I heard KSM in Point Reyes, California on 8.438MHz, WLO in Mobile, Alabama on 8.658MHz and NMC in California on 8.574MHz.

I listened on 80m, 40m and 20m but heard nothing, other than a lone W station calling K6KPH on 40m.

KSM/ K6KPH broadcast regularly and can be heard in the UK, although they are always weak with me at this point in the solar cycle.

Its nice to hear CW being used on these bands again. You can find out more from the Maritime Historical Radio Society web site on http://www.radiomarine.org

Thursday, 8 July 2010

HF Prediction Podcast, Summer 2010


Report for Summer 2010 with a look at how the MUF stays high after dark, how to interpret sunspot numbers and how to use the solar wind indicator on solarcycle24.com. Just click on the headline above or search for G0KYA on iTunes.

Thursday, 1 July 2010

HF Propagation and charts - July 2010


Solar conditions continue to be fairly poor. As I write this on 1 July there is a solitary sunspot (number 1084) which has pushed the solar flux up to 75, but this is nothing special. Strong southward-Bz-pointing solar winds are also causing the K index to rise at times causing havoc.

The sunspot number is currently 11. This doesn't mean there are 11 sunspots – you get 10 for each group and one for each sunspot. So one sunspot in one group (naturally) leads to 10+1 =11.

Some people have suggested that the bands are improving, but I think they are confusing Sporadic E (Es) openings with F layer. This seasonal effect is opening up 20-10m and even 6m and 2m with good, strong openings up to 1,300 miles.

Multi-hop Es is stretching this even further, but we are not seeing an improvement in F layer propagation and Es will be less prevalent as the summer wears on.

Mid-to-late September will be the acid test – and with flux levels in the 70s we are not going to see many trans-Atlantic openings on 10m. Sorry!

In summer, Daytime MUFs are likely to be lower than those of winter. But night-time MUFs may be higher in summer than those in winter, so check 14MHz after dark for some nice surprises. Greyline around sunrise in summer can also be good – Peter M0RYB worked Hawaii on CW using a vertical half wave dipole for 20m that he is testing the other week.

Now let's look at each band and what you can expect.

On 160m (1.8MHz or Top Band), high levels of static and solar absorption mean that the band will not really support sky-wave contacts during the day. During darkness, short-skip openings may occur, but DX may be a rarity. Occasional openings can occur during the hours of darkness, especially around local midnight/early hours.

80m (3.5MHz) will generally follow the characteristics of Top Band with high levels of static, but will also provide good openings out to around 250 miles during the day. Absorption will grow to a maximum at midday for inter-G contacts. DX capabilities will be poor to fair during the hours of darkness.

40m (7MHz) will suffer from high static caused by high numbers of thunderstorms. Nevertheless, night-time openings should be reliable from sunset to sunrise. Local daytime openings will be possible on the whole. Night-time skip distances are likely to be between 500 and 2,300 miles.

20m (14MHz) is still likely to be the best DX band between sunrise and sunset, although the band will be noisier than the winter period and not as reliable for long-haul contacts. The higher MUFs at night mean that 20m may remain open during the evening to DX. Short skip may also be possible due to summer sporadic-E.

17m/15m (18MHz/21MHz) should provide a fair number of DX openings during daylight hours, especially to the southern hemisphere. Once again, 15m may struggle to open at times. Both bands are likely to close after sunset. Sporadic-E will provide good short-skip openings, predominantly in the May-June period.

12m/10m (24MHz/28MHz) are likely to be disappointing bands apart from Sporadic-E openings that will provide regular openings out to around 1,300 miles. Multi-hop sporadic-E openings are possible, providing relatively good, but short-lived paths to DX beyond this range. A typical multi-hop opening might provide brief contacts with the Middle East or USA, although they would be very hard to predict.

You can find HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/

You can also listen to Steve G0KYA's HF propagation podcast on iTunes or at http://www.g0kya.blogspot.com/


Steve G0KYA

RSGB Propagation Studies Committee

Monday, 14 June 2010

HF Propagation, June 2010

Solar conditions continue to be fairly rotten. In May we had a solar flux low of 69 and a high of …. wait for it …. 83. Hardly what we would expect for the rising part of the new cycle. It really needs to get over 100 if we are to see the higher bands open up to good F2 layer DX. Even then, we are going to have to wait until the Autumn.

But the good news is that the Sporadic E season is opening up the bands nicely, albeit for relatively short skip distances.

Look for very strong signals on 10m and 6m, which will suffer from heavy QSB. As the Es clouds move the countries you are able to work will change.

Peak times for Es are mid morning and mid to late afternoon, although look in the evening too.

Otherwise, Daytime MUFs are likely to be lower than those of winter. Night-time MUFs may be higher in summer than those in winter. Note that DX on the low bands, if possible, is unlikely to occur until around midnight or the early hours due to the late sunset.

But for now, let's look at each band and what you can expect.

On 160m (1.8MHz or Top Band), high levels of static and solar absorption mean that the band will not really support sky-wave contacts during the day. During darkness, short-skip openings may occur, but DX may be a rarity. Occasional openings can occur during the hours of darkness, especially around local midnight/early hours.

80m (3.5MHz) will generally follow the characteristics of Top Band with high levels of static, but will also provide good openings out to around 250 miles during the day. Absorption will grow to a maximum at midday for inter-G contacts. DX capabilities will be poor to fair during the hours of darkness.

40m (7MHz) will suffer from high static caused by high numbers of thunderstorms. Nevertheless, night-time openings should be reliable from sunset to sunrise. Local daytime openings will be possible on the whole. Night-time skip distances are likely to be between 500 and 2,300 miles.

20m (14MHz) is still likely to be the best DX band between sunrise and sunset, although the band will be noisier than the winter period and not as reliable for long-haul contacts. The higher MUFs at night mean that 20m may remain open during the evening to DX. Short skip may also be possible due to summer sporadic-E.

17m/15m (18MHz/21MHz) should provide a fair number of DX openings during daylight hours, especially to the southern hemisphere. Once again, 15m may struggle to open at times. Both bands are likely to close after sunset. Sporadic-E will provide good short-skip openings, predominantly in the May-June period.

12m/10m (24MHz/28MHz) are likely to be disappointing bands apart from Sporadic-E openings that will provide regular openings out to around 1,300 miles. Multi-hop sporadic-E openings are possible, providing relatively good, but short-lived paths to DX beyond this range. A typical multi-hop opening might provide brief contacts with the Middle East or USA, although they would be very hard to predict. Propagation via the F layer is unlikely to occur reliably until Autumn.

You can find HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/

You can also listen to Steve G0KYA's monthly HF propagation podcast on iTunes.

Steve G0KYA
RSGB Propagation Studies Committee

UK HF propagation charts, June 2010


Later than usual as I've been working away, but here are the UK prop charts for June. Please note that these don't predict Sporadic-E conditions. These will give short skip on bands from 14-50MHz, with occasional openings on 2m too. The Es season appears to have been quite good this year, leading many people (falsely) to believe that solar cycle 24 is romping along. It isn't!

See www.infotechcomms.co.uk/propcharts

Wednesday, 26 May 2010

Moxon beam for 2m (144MHz)


I was reading Practical Wireless the other day and found a piece about the PW 2m QRP contest on Sunday June 13 2010. I've never taken part in this, but thought that I might make the effort this year.

I have a Yaesu FT-817 and a couple of SLA batteries, but I haven't got a 2m beam. I used to own a 4el quad by Jaybeam which was brilliant, but sold it as I thought I would never use it again – duh! I looked at a few manufacturers' websites, but £50 for a 5el Yagi seemed a bit steep for one-day's operating.

So I decided to make my own. I wasn't interested in outright gain, but wanted something which was a) small and light, b) cheap and c) offered a little gain and some front to back.

The answer tuned out to be a Moxon rectangle beam. This is a two-element beam offering about 3dBd gain and massive 30dB front to back

If you head over to http://www.moxonantennaproject.com/wb5cxc/wb5cxc.htm you can find out all about it.

There is even a PC-based calculator that you can download.

So I headed off to B&Q and came back with 2m of white PVC trunking, two connector unions, and some PVC glue. I added some 2m PVC coated copper wire that I had, an S0239 socket and some 3.5mm heatshrink tubing – that's it. About £10 all in.

I modelled the beam for 145MHz and came up with the dimensions shown below. I then cut the PVC pipe accordingly and soldered/glued it all together. I used the heatshrink tubing to connect the ends of the elements. If I were making another one I would use a drinking straw first to strengthen them, although they seem OK with the tubing on its own.

Using my MFJ analyser I found that it resonated at about 136MHz – damn! I think this is because the velocity factor of PVC coated wire is about 94-95% and the computer simulation assumes bare wire.

So out came the junior hacksaw and I cut everything down to 94% of the original. This gave me a beam with about a 1:1.2 – 1:1.5 SWR across 2m. I fitted the beam to a 10m fishing pole (about 2m down from the top) using a couple of cable ties and hauled it up. I used 20m of Mini8 coax, but later that day found that it had a measured loss of about 2.4dB on 144MHz. Switching to RG213 reduced this to about 1dB.

So does it work? Yes, and quite well. I was able to hear the GB3VHF beacon at about S1-2 (148.20 km (92 miles) away). Swinging the beam around made the signal vanish into the noise. I could also hear the PI7CIS beacon in the Netherlands (JO22DC) - 221.11 km (137.4 miles). Swinging the beam vertically brought in repeaters from up to 60 miles away too. This was under flat conditions and I was unable to raise anyone on 144.300MHz SSB, more's the pity.

So for a total cost of about £10 a great little lightweight beam.

Friday, 7 May 2010

HF Propagation Podcast - May 2010


Still very few sunspots at the moment, but lots of coronal hole activity! This month I also take a look at WinCap Wizard from Tabersoft. You can listen by clicking on the headline or search for G0KYA on iTunes.

Friday, 30 April 2010

HF Propagation report, May 2010

Solar conditions have not been very good in the last month. In fact we had a run of about 12 days without a single sunspot. With the solar flux hovering around 74 it was like a return to the minimum once again.

Solar flare activity has been low, but even a small change in the Interplanetary Magnetic Field (Bz) swinging south was enough to cause the HF bands to misbehave.

This was characterised during the International Marconi Day event on 26 April. The morning was not too bad with DX from the Caribbean and VK being workable on 20m in the mid morning. By afternoon is was EU only.

May 1 should see the start of the Sporadic E season. This is characterised by very strong signals in the 14-50MHz bands, with very occasional openings on 2m.

Look for very strong signals on 10m and 6m, which will suffer from heavy QSB. As the Es clouds move the countries you are able to work will change.

Peak times for Es are mid morning and mid to late afternoon, although look in the evening too.

Daytime MUFs are likely to be lower than those of winter. Older books suggest this is due to the ionosphere heating up with resultant lower ion densities. But other theories suggest that this is due to a change in ionospheric chemistry between winter and summer.

The so-called “Seasonal Anomaly” is now thought to be due to a large summer electron loss rate caused by an increase in the molecular/atomic composition of the ionosphere and the reaction rates being temperature sensitive.

It is not all bad news though. Night-time MUFs may be higher in summer than those in winter. Note that DX on the low bands, if possible, is unlikely to occur until around midnight or the early hours due to the late sunset.

So let's look at each band and what you can expect.

On 160m (1.8MHz or Top Band), high levels of static and solar absorption mean that the band will not really support sky-wave contacts during the day. During darkness, short-skip openings may occur, but DX may be a rarity. Occasional openings can occur during the hours of darkness, especially around local midnight/early hours.

80m (3.5MHz) will generally follow the characteristics of Top Band with high levels of static, but will also provide good openings out to around 250 miles during the day. Absorption will grow to a maximum at midday for inter-G contacts. DX capabilities will be poor to fair during the hours of darkness.

40m (7MHz) will suffer from high static caused by high numbers of thunderstorms. Nevertheless, night-time openings should be reliable from sunset to sunrise. Local daytime openings will be possible on the whole. Night-time skip distances are likely to be between 500 and 2,300 miles.

20m (14MHz) is still likely to be the best DX band between sunrise and sunset, although the band will be noisier than the winter period and not as reliable for long-haul contacts. The higher MUFs at night mean that 20m may remain open during the evening to DX. Short skip may also be possible due to summer sporadic-E.

17m/15m (18MHz/21MHz) should provide a fair number of DX openings during daylight hours, especially to the southern hemisphere. Once again, 15m may struggle to open at times. Both bands are likely to close after sunset. Sporadic-E will provide good short-skip openings, predominantly in the May-June period.

12m/10m (24MHz/28MHz) are likely to be disappointing bands apart from Sporadic-E openings that will provide regular openings out to around 1,300 miles. Multi-hop sporadic-E openings are possible, providing relatively good, but short-lived paths to DX beyond this range. A typical multi-hop opening might provide brief contacts with the Middle East or USA, although they would be very hard to predict. Propagation via the F layer is unlikely to occur reliably until Autumn.

You can find HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/

You can also listen to Steve G0KYA's monthly HF propagation podcast on iTunes or at http://www.g0kya.blogspot.com/

Steve G0KYA
RSGB Propagation Studies Committee

UK HF propagation charts, May 2010

My HF Propagation maps for May 2010 have now been published. Please note that these don't predict Sporadic-E conditions, which should start around the 1st May. These will give short skip on bands from 14-50MHz, wtih occasional openings on 2m too.

If you monitor 28 or 50MHz you'll hear stations from around southern Europe and into Scandinavia. Signals will be strong, but with heavy QSB. They may be fleeting as the Es clouds move. Peak times will be mid morning and late afternoon, but could occur any time, including evening.

See www.infotechcomms.co.uk/propcharts

Thursday, 8 April 2010

HF Propagation Podcast - April 2010


Few sunspots at the moment, but lots of solar flare activity - boo! Find out more and also hear about the origins of Sporadic E in this month's Podcast. You can listen by clicking on the headline or search for G0KYA on iTunes.

Wednesday, 7 April 2010

HF Propagation report - April 2010

As the new cycle progresses we are starting to see more solar flare activity which is bringing aurora with it.

Over the past month we had a solar flux low of 76 and a high of 92 (on 13th March). But we've also had some serious solar flares. We had a geomagnetic A index low of 1 on two occasions and a high of 28 in the first week of April.

In fact, the A index was still climbing as I wrote this and Auroral conditions were being recorded on 6m and 2m

We are still in the equinox period as far as HF propagation goes. These tend to be the best months for working North-South paths, such as UK to South Africa.

So let's look at each band and what you can expect.

On 160m (1.8MHz or Top Band), look for short-skip and DX openings at night. Little daylight skip will be possible due to absorption, but openings out to 1,300 miles and occasionally further afield can be expected at night with conditions peaking around midnight and again at sunrise (greyline).

80m (3.5MHz) will generally follow the characteristics of Top Band at night, but will also provide good openings out to around 250-300 miles during the day. These will lengthen to around 500-2,300 miles at night with fairly good DX opportunities at times.

40m (7MHz) Forty metres should open to DX in an easterly direction at sunset. Openings to the west should be possible after midnight and should peak just before sunrise. Contacts should be possible during the day, although lower critical frequencies may mean that it is difficult to work other UK stations while perfectly possible to talk to European stations. If the flux rises then 40m may open up to NVIS contacts around the UK, but 80m will be better.

20m (14MHz) is likely to be the best DX band between sunrise and sunset. The bands may occasionally open after dark, perhaps to the southern hemisphere. Good openings will be possible during daylight hours out to around 2,300 miles.

17m/15m (18MHz/21MHz) should provide fairly good DX openings during daylight hours, especially to Africa and South America, with 17m being open more often than 15m. If we get more sunspots 15m will become a great DX band, as it did at times in February. Both bands are likely to close after sunset.

12m/10m (24MHz/28MHz) These could be disappointing bands if the solar flux remains low. If the solar flux heads towards the high 80s/90s then openings will occur on both bands, although 24MHz will open first. If it breaks the 100 mark then expect to see some good DX openings on 10m. Expect to see Sporadic E start up at the end of the month, but more of that in May.

You can find HF short-path propagation prediction charts from the UK at:

http://www.infotechcomms.net/propcharts/

You can also listen to Steve G0KYA's monthly HF propagation podcast on iTunes or at http://www.g0kya.blogspot.com/

Steve G0KYA
RSGB Propagation Studies Committee

Friday, 2 April 2010

Propagation charts for April 2010


I have just updated the propagation charts for April 2010 from the UK. The solar flux is actually quite low now and we are not seeing the rapid rise that you would expect at the beginning of the cycle. However, DX is out there, especially on North South paths. Expect to see Sporadic E starting up at the end of the month. Last year it was like a switch being thrown on 1 May.

We have Marine Radio Day on 10th April and International Marconi Day on 24 April. I have also done prop charts for the latter.

See http://www.infotechcomms.net/propcharts/

Monday, 1 March 2010

UK HF propagation charts, March 2010

I've updated the short-path propagation prediction charts for March 2010. We should see some nice north-south paths on 21MHz if the solar flux comes up. We should also see 14MHz open to a lot of world.

See http://www.infotechcomms.net/propcharts/

G0KYA's HF Propagation Podcast for March 2010

Solar Cycle 24 is under way, but we are not out of the woods yet. The last month has seen great DX openings when the flux hit the mid 90s, but now the sun is virtually spotless again.

Click on the headline link to listen to the Podcast or find it on iTunes.

Tuesday, 23 February 2010

MKARS 80 LSB QRP transceiver


I have just finished my MKARS 80 LSB QRP transceiver kit - it took me about 10 weeks to complete on and off. The MKARS 80 is a kit from the Milton Keynes ARC and, while complex, can be built by anyone capable of reading and wielding a soldering iron. The slowest bit was cutting out the case and making the front panel.

I would like to say it worked first time, but it didn't. I wound the toroids incorrectly first off (read the instructions!) and had a short that I eventually fixed. Both builder error!

First QSO was with the homebrewers' net who said that it sounded great. I got 55-57/8 reports from around the UK using 5W and an 85ft end fed (W3EDP). If you are sharp eyed you will see that it says M6ELE on the box. This is my daughter's callsign and I thought it might encourage her to use it. I am using a cheap computer mic off Ebay, which came with two stones wrapped in Chinese newspaper inside for ballast! Maplin knobs as usual. The receiver is fantastic - I heard Japan when the board was just laying on the bench.

If you want more info see http://www.radio-kits.co.uk/mkars80page.html

I used Photoshop Elements to make front panel, which was then coated in plastic film and Spraymounted on. The case was sprayed with PlastiKote Velvet Touch - strange stuff , spray it when it is warm and keep about 40cm away. You end up with a stipple finish, but it is soft and marks easily.

Tuesday, 16 February 2010

Running Propagation Prediction Software on Mac OS X


I use a Mac for most of my work - I still have a couple of PCs, but prefer the user experience with a Mac. I gave PCs up after running anti-virus software, registry cleaners et al on my Windows XP machines every other day, but that is another story.

I can run Windows XP using Parallels on my Mac, but it is memory intensive and slows down the machine, not to mention making the fan run solidly. Also, while running XP the clock gets out of sync very quickly, making the IBP beacon software useless within a minute or so.

So can you run programs like W6ELProp and VOAProp on a Mac in any other way. Well, yes you can.

Download Wine for Macs or Wineskin and you can run PC emulation. This doesn't appear to use up as many resources as full-blown Windows and works well.

I now have both W6ELProp and VOAProp running as and when I want them, and the clock stays perfectly synchronised.

You can get Wine for Macs at http://www.winehq.org/ or Wineskin at http://www.winehq.org/

If you are not aware VOAProp was written by Julian G4ILO and is a brilliant HF prediction program that uses the VOACAP engine. It also has a real-time graphical display of the IBP beacon network. W6ELProp is older and written by Sheldon Shallon. It uses a Fricker model of the ionosphere and is better than VOACAP at low band (80m ) predictions. It is getting clunky now, but is still very useful.

Friday, 12 February 2010

UK HF propagation charts, February 2010


Here are the latest HF propagation charts for the UK. Propagation has improved dramatically. We are seeing the occasional opening on 10m (Israel today) and 15m has been open to the mid west and west coast of the USA. VE7 (Vancouver) has been booming in on 14MHz at local sunset.

These are based on 100W to a dipole at 35ft, with a smoothed sunspot number of 20. They are all short path too. You can try them here.

G0KYA's HF Propagation Podcast for February 2010


HF prediction podcast for February 2010. More positive this month as Solar Cycle 24 gets under way. Also a quick look at www.solarcycle24.com - click on the heading to listen to the podcast.