21 mHz Signals Make Spectacular Appearance

13 metres has always been a band that I've watched and found quite interesting during periods when the sunspot count is up in higher parts of each cycle.  Because of this band's rather unpredictable propagation characteristics, you just never know when signals might poke through the noise.

Currently here in eastern Australia, the band is open during most days but can close up by 1100 in the evenings, often not re-opening until 2300 next morning. Many of the "middle-of-the-night" stations scheduled for operation between 1100 and 2300 just can't be heard in my part of the world. Yet, when conditions are right (which is not very often these days), signals can still be noted well into the late evenings/early mornings. In other words, it is still worth checking this end of the shortwave spectrum for the occasional openings when you least expect it.

Another characteristic of this frequency range is that propagation can often be quite region specific. Some nights, Europeans will be heard well, but on other days the Middle East transmitters (and perhaps the Spain/Portugal region) will dominate. Then on other occasions, expect the band to suffer from quite a few "bad" days when very little is heard at all.

The 13 metre band will yield its best results when signals can travel across mostly daylight paths from transmitter to receiver, and long distance propagation will be more successful under those conditions. Australia's Ionospheric Prediction Service (IPS) currently indicates that frequencies above 12 mHz can be unreliable during our evenings (periods of darkness). The maximum useable frequencies (MUF) and optimum working frequencies (OWF) fall dramatically from around 0800 UTC (and even earlier for certain paths) and don't recover again till around 2200.  This is especially evident in the 13mb at the top of the SW spectrum. As winter approaches in my part of the world, longer darkness hours will greatly affect even more the behaviour of the ionosphere for the higher frequencies. In mid-winter, we can expect that the 13mb will be rendered useless for all intents and purposes.

However....... (there's ALWAYS an "However"!!!)...........

Last night, Thursday February 28, I noted some rather spectacular reception of broadcasters on the 13mb, at times when the band is usually long closed! Stations from Europe, Africa and the Middle East were noted in the logbook. Signals were quite variable, and often changed strength over very short periods of time. In fact, several stations were heard for only a few seconds to several minutes before fading away into the night! But others were quite strong throughout the evening.

THIS is what makes listening to the 13mb so interesting and enjoyable - the expectation and anticipation of waiting for signals to appear, never knowing when they might surface, and watching the behaviour of each station as it's signal strength changes with ever-evolving propagation conditions.

As my friends in the northern hemisphere should find, the next few months will perhaps see increased activity on this band as their summer approaches.

So, here are my observations from last night's listening session:

21470   SEYCHELLES.  BBC - Mahe. Came rocketing in at 1115 with the English service. Hasn't been heard this strong at this time for several months. Faded out around 1225.

21480   IRAN.  VOIRI - Sirjan.  30 min broadcast to Africa in Hausa at 1143. Variable signal, on the weak side. 

21505   SAUDI ARABIA.  BSKSA - Riyadh.  S/on 1200 for Arabic to Nth Africa. Fair level throughout this broadcast.

21540   KUWAIT.  R. Kuwait, Arabic service with a strong signal at 1120 to Europe. No sign of Spain at this time.  And then later - 1150 - REE - Noblejas appeared briefly and battled it out for a few minutes before becoming submerged again. Both stations gone by 1315.

21570   ROMANIA.  RRI - Tiganesti. S/on 1200 with IS and ID for the one hour service to Africa. Fair signal right up to their 1300 s/off.

21575   IRAN.  VOIRI - Kamalabad. The English service to South Asia is scheduled between 1030 and 1103, and was noted here at 1105 with a beautiful signal.

21580   FRANCE.  RFI - Issoudun. French to Central Africa, first noted fading in around 1207 with a fair signal strength.

21590   CHINA.  CNR 1 Jamming at s/on 1300 to 1330. What are they targeting here?? Surely not the BBC Uzbek service?? Booming signal.

21595   UNITED ARAB EMIRATES.  BBC - Dhabayya. Nice signal for the 30 min Somali service 1100-1130.

21610   SPAIN.  REE - Noblejas. Gigantic signal at 1130 to Mid East/ nth Africa in Spanish. Faded by 1335.

21630   ASCENSION IS.  BBC -  Ascension for the 30 min service in French to Africa between 1200 and 1230. Kept coming back to this frequency every few minutes, hoping it would appear, and sure enough it did at 1216 and again at 1228….for a matter of seconds!  :-)

21670   SAUDI ARABIA. BSKSA - Riyadh. Lovely signal with only a little fading for the Indonesian service, first noted at 1135.

21680   VATICAN.  VR - S. Maria di Galeria. Italian service s/on 1300 to 1315, weak but readable.

21690   FRENCH GUIANA.  RFI - Montsinery. After many passes across the band, this one finally popped up for me at 1231 for French to Africa. Poor signal when it did finally appear, but pleasing to be able to hear it. Disappeared on many occasions only to return briefly. Waited till 1330 for the transmitter changeover to Issoudun for a continuation of the French service but heard nothing.

21780   RWANDA.  DW - Kigali.  Kept monitoring this frequency on-and-off for over 45 minutes. Was surprised when I finally managed to hear a few words of French at 1252, just before the scheduled change to Hausa at 1300. Pleased with my patience!!!

21800   IRAN.  VOIRI - Sirjan. Hausa service to Africa, 1148. Poor to fair signal before s/off at 1200.

After all that, I stumbled off to bed at 1:30am, feeling quite satisfied with the results of my listening.

Best 73 everyone,

Rob VK3BVW






POSTSCRIPT:

Further to the above post, the following evening saw the band is quite different shape, with not much around except a very strong Vatican Radio!

21650 VATICAN. VR - S. Maria di Galeria. Wonderful signal tonight, Friday March 1 with the English Mass broadcast at 1130-1200. Transmission on this frequency at this time only on Fridays. Check out audio quality on Soundcloud!

Vatican Radio 21650 kHz

Rob