The first weekend of May each year hosts a Europe-wide VHF/UHF contest. It’s one I always look forward to: there’s a decent chance of tropo on some of my favourite bands (unfortunately not this year); a slim chance of Es (definitely not this year!); and, most reliably, it’s around the peak of the Eta Aquariids meteor shower.
Eta Aquariids meteors are quite unusual because they are relatively swift (at 66.9km/s) compared with many other shower meteors. When seen visually, they leave long and persistent trains in the night sky. In a similar fashion, from a radio perspective they often result in long and intensely strong “bursts”. Combined with a decent peak hourly rate of 40 and a lot of QRO, well-sited stations all over Europe, this can make for some interesting listening! This year did not disappoint with many bursts heard on 144MHz, some lasting tens of seconds.
A step up from simply tuning around searching for meteor-scatter bursts is to use a Software Defined Radio (SDR), with appropriate software, to record a portion of spectrum to hard disk for a period of time. This data can then be viewed after the event, tuning across the recorded spectrum as if it was in real-time. As an example, I used Simon Brown’s excellent SDR-Radio suite (Version 2.3 in my case) to do just that at various points through the weekend, capturing several very good meteor bursts.
Included below is a video of me using SDR-Radio’s data file analyser to play back signals captured during one good burst on 144 MHz, which I’ve annotated with information about each station received, wherever possible. Enjoy!
This data was captured in IO51vw using an 11el F9FT antenna at 6m a.g.l., azimuth 095 degrees, a mast-head preamp into an active 0dB loss splitter, feeding an RTL SDR dongle on one port. The recorded spectrum was originally 1MHz wide, centred at 144.280MHz, but I’ve used the data file analyser to zoom in such that the spectrum now covers from approximately 144.150 MHz to 144.410 MHz.
The 6m transatlantic path via aurora has been reported before by others and is certainly nothing new, but I’m beginning to wonder if it’s more viable than many might think. We had another decent aurora on 31st December, most of which I missed due to the New Year’s Eve celebrations, but I decided to check westerly conditions when I returned home sometime after midnight.
Once again I was surprised to find the VE4ARM beacon (EN09at, 6011km) at a good strength at approximately 01:40z (Jan 1st) followed about ten minutes later by VY0SNO (FP53rs, 3653km). The opening was again quite short but there’s a possibility the path might have also existed earlier in the evening? After I had spotted the beacons on the dx cluster, VE4ARM was reported by Tim, G4FJK in IO80 at a great distance of 6346km, and the VY0 beacon was reported from PA and DL.
One fascinating little snippet: This time I managed to grab a decent recording of VY0SNO just before it faded. Listen very carefully to this clip, and you may be able to detect a sudden doppler shift of about +10Hz, 21.5 seconds in, coinciding exactly with a steep drop in the signal strength. I think that helps visualise the auroral-Es path dynamics rather nicely!
On the 17th December, shortly after 09z, there were two solar coronal mass ejections (CMEs) in rapid succession, both of which directed at least some of their ejecta towards the Earth. This was fair warning of the possibility of aurora due some time on the 19th, depending on exactly how fast the material was traveling. The strength of any aurora would also depend on the alignment of the Interplanetary Magnetic Field; for maximum effect we would need a strong southerly component.
As anticipated, the CMEs passed the ACE spacecraft at 13:05z on the 19th, hitting the Earth approximately one hour later. The good news, from our point of view, was that the IMF had a significant southerly component for much of the time, resulting in excellent coupling of the CMEs into the Earth’s magnetic field causing a nice strong aurora!
It’s been some months since we’ve seen any sort of decent tropo opening on VHF/UHF, in this part of Europe at least. However, there really was no excuse for being unaware of this one in advance because the forecasting websites (F5LEN and Hepburn) had been predicting something nice for the end of September for at least week prior. It turned out to be exceptional!
I’d been keeping an eye on the F5LEN and Hepburn Atlantic tropo forecasts prior to the 20th of May because they looked promising for good propagation towards the south:
Hepburn North Atlantic forecast 06z May 20, 2015
F5LEN Atlantic forecast 00z 21st May, 2015
Lots of bright colours over much of the North Atlantic! There looked to be some possibility of a repeat of Dave, PJ4VHF’s incredible reception of the Cape Verde beacon, over a distance of some 4700km (and perhaps further?), as well as a north-south path touching on Ireland.
Up until lunchtime on the 20th there was nothing other than a slight enhancement on my AIS receiver (a useful propagation tool at 162MHz, online at MarineTraffic) showing ships slightly further south of Cork than usual – certainly nothing exceptional. I wasn’t even hearing the stalwart ED1ZAG beacon in IN53 but the forecast maps were marginal for that direction.
At approximately 14:35z, a weak cw-keyed signal appeared just very slightly above 144.436MHz, rapidly becoming strong enough to identify as D4C in HK76mv! The Monteverde Contest Team’s beacon is at a distance of some 4165km from EI3KD, with a tolerance of five kilometers or so, which probably makes it the furthest tropo distance yet heard from within IARU Region 1.
My main effort for the May UHF/SHF contest weekend this year was to activate IO51 on 3cm (10GHz). I had tried to do the same last year but discovered a problem with the transverter’s local oscillator (LO) producing too little power, meaning the activity had to be aborted. Since then, with the help of John EI2FG, I had fixed the LO and everything seemed to be working fine.
Unfortunately, I can only erect the 3cm station on a temporary basis and it is quite a lot of work but, if I’m going to try it at all, the SHF contest weekends are the time to do it! Luckily I had a few contacts which made it worthwhile – in fact I had more success on 3cm than on 70cm where (admittedly with very little time spent there) I worked the one station I heard all weekend…
The aurora of 17th March 2015, St Patrick’s Day, was a superb event: It was good enough to propagate signals on 50MHz across the Atlantic, which I found particularly interesting. Unfortunately I haven’t had much time to get anything in the blog about conditions on 144MHz, so here’s an effort to get at least something recorded!
The QSO map for 2m looked like this:
EI3KD (IO51vw) QSO map for 144MHz during aurora on 17th March, 2015
I spent most of the afternoon and early evening hours during the “St Patrick’s Day” aurora on 144MHz but when that started to fade I thought I’d follow the aurora westwards, listening on 50MHz where I had already heard a few very strongly auroral GMs, peaking at an azimuth of around 320/330˚.
At 21:02z I heard a weak and different-sounding signal, certainly auroral but more “Tone 5” than “Tone A”. After peaking the signal at an antenna azimuth of approximately 295˚, it turned out to be K2PLF in FM19 at a distance of 5272km! Unfortunately my 100 Watts wasn’t enough to be heard by him but it was the start of a fascinating couple of hours, listening to many weak signals popping up as stations in the USA and Canada called and worked each other.
A baby 70cm station is born, ready for action!
2m (11el F9FT) and 70cm (19el F9FT) at EI3KD
Some months ago I added a 432MHz 19el F9FT antenna to the mast (approximately 4.5m a.g.l.), with the help of G4CLA – thanks Pete! My FT857D is capable of 20 Watts output on 70cm, but I did find an old sspa that, with a reduced drive from the rig, bumped it up to a massive 30 Watts! Every decibel counts, right? Anyway, the sspa’s built-in preamp was probably a small improvement over the rig’s front-end. Even with such a small set-up I’ve managed to give away a few points in the RSGB UKAC 70cm contests, and also had a few DX contacts during brief spells of enhancement. I also have a higher power sspa to modify for 432MHz, but that’s another story.
Since added the 70cm antenna I’ve been looking forward to a decent tropo opening, and early February wasn’t going to disappoint! Apologies for the length of the blog that follows, but it was an exceptional tropo opening…
Worked and heard maps 8-12 Feb 2015
144MHz worked and heard, 8-12 Feb 2015
432MHz worked and heard, 8-12 Feb 2015
Lance, W7GJ, is well-known for his 50MHz EME exploits, both from his home location and abroad from many exotic locations expedition-style. Details of his activities along with a lot of useful information regarding 6m EME can be found on his website. When terrestrial propagation is poor, I sometimes set the 6m 6el antenna towards the setting Moon to “see” what is happening: On the 30th December 2014 I noticed that Lance was a very good and consistent signal via EME, at -19dB in JT65A. I decided, rather tongue-in-cheek, that I’d call him with the barefoot FT857D (i.e. certainly no more than 100W in the shack, and somewhat less into the antenna 150m away) – To my amazement, and thanks in no small part to Lance’s tenacity, we managed to complete a QSO! It took quite a while and required all of Lance’s skill to dig my signal out of the noise, but it just goes to show what’s possible as long as we try. I really recommend everyone to at least take a look for Lance’s EME signal and perhaps give it a go – not least because his QSL card is rather nice 😉
F2 propagation on 50MHz reached Irish latitudes on 2nd February, which can’t be a bad sign as we approach the Spring equinox. The opening could have been easily missed, were it not for the Senegal beacon 6V7SIX (50.013MHz): This was the only signal heard for a while (at a good 599), but widespread reporting on the packet cluster probably encouraged Francis, 6W7SK (aka F6BLP), to come on to the band. Francis was a good signal here, resulting in a nice contact using my barefoot FT857D to the 6el LFA2.
I made this recording shortly after our QSO, of Francis calling CQ on CW…