Sassi dal digitale

E' confermato. Andrea Borgnino mi scrive che la Rai, a quanto gli avrebbero riferito i suoi colleghi, parte con i test del DRM, Digital Radio Mondiale (alias Digital Noise Mondiale), agli inizi di aprile dai 693 kHz che furono dell'onda media di Milano 2 (località Siziano, ben visibile dal finestrino del treno sulla Milano Genova tra Milano e Pavia). La potenza è pazzesca per questo tipo di prove, 20 kW, sufficienti per azzerare la ricezione delle onde medie a Milano in un raggio di almeno 60 kHz. Tutto questo per un cavolo di standard digitale che nessuno, se non pochi appassionati muniti di convertitori di media frequenza e computer possono ascoltare.
Ha perfettamente ragione Ullmar Qvick, un appassionato svedese che su DX Listening Digest di qualche giorno fa ha reso nota una sua lettera - qui riportata - inviata alla responsabile del Dipartimento radiofonico della European Broadcasting Union, per descrivere l'assurda situazione in cui vengono a trovarsi i pochi superstiti ascoltatori delle onde medie (forse neanche così pochi se pensiamo che diversi automobilisti accendono le onde medie quando l'FM è troppo debole o disturbata) quando provano a sintonizzarsi su un canale analogico che ha la sventura di trovarsi nelle immediate vicinanze di un broadcaster impegnato a sperimentare segnali decodificati, a fatica, da meno di cinquanta persone in tutto il continente. Molto sommessamente Qvick suggerisce che forse sarebbe stato il caso di pianificare meglio queste prove, magari riservando loro uno spazio apposito di questa banda. Tra l'altro il valore di queste continue prove si diluisce nel tempo. Quelle strumentali, propagative, sono già state fatte, che senso ha protrarle all'infinito? E c'è da chiedersi anche se le prove di decodifica basate su software e computer general purpose abbiamo poi tanta ragion d'essere in un dominio di fruizione che finora se l'è cavata benissimo con dispositivi di ricezione integrati e compatti. E che si suppone dovrà pur continuare su questa strada (o vogliamo portarci in tasca un bel set-top box aggiuntivo, come per il televisore digitale?). Insomma, sto benedetto DRM ancora non ha una vera e propria audience. Non ce l'avrà finché non ci saranno degli apparecchi dedicati capaci di fare a meno di software e computer. Nell'attesa, i signori ingegneri non potrebbero piantarla lì con le loro prove?

Mrs. Raina Konstantinova Director of the Radio Department European Broadcasting Union Geneva, SWITZERLAND

Dear Mrs. Konstantinova:

I am writing this letter to you because of my worries concerning the present situation on the Medium Wave broadcast band here in Europe. It's far from an exaggeration to state that we as listeners experience an increasing chaos after the introduction of DRM tests on these frequencies.
Before I go on, I would like to tell you a little about my background. I have been profoundly interested in world radio ever since my childhood. I started listening to international broadcasts on shortwaves and European medium wave stations at the age of eleven, back in 1945, keeping a log book of the stations I heard. Our Swedish radio weekly magazine "Rˆster i Radio" at that time was a great help with information and frequency lists of LW. MW and SW stations already at that time. In my archives there are confirmations from broadcasting stations in 155 countries that I have heard their transmissions. I have also been a transmitting radio amateur for a number of years and the producer of a local radio programme for three years. In other words, I know very well the reality I am writing to you about.
Today, on January 17th, EBU participates in the celebration of "Art's Birthday". Innovative, non-traditional musical art has been supported by the broadcasters, its development and the interest of the public has been very much depending on the broadcasting media, the radio and television. So the event tonight, broadcast all over Europe, is a very positive one. But my thoughts and concerns, when I heard about Art's Birthday, went in another direction:
Art connected with daily life, music which takes elements from the reality around us. Good. Then I thought: If someone made a recording of Hessischer Rundfunk, listening any time on 594 kHz Medium Waves, somewhere outside Frankfurt, this could be used as a musical satire. Take sections of this recording where the German broadcast is often drowned by the mill-like noise from the Croatian DRM test on the same frequency. A (nominal) 10 kW transmitter down in Croatia has got the power of overriding a 250 kW+ transmission in Germany, when you listen within the normal reception zone for this transmitter!
And together with this segment of recording, the musical artist could create the satirical effect: A recording from the years of the Cold War, in which a Soviet jamming transmitter almost drowns the Voice of America or BBC transmission in Russian!
THE TERRIBLE THING IS THAT TO US LISTENERS, THE SITUATION OF THE COLD WAR HAS COME BACK!
Dear Mrs. Konstantinova, I would like to know what the EBU is going to do to make the situation for us listeners tolerable. It seems to me, maybe I am wrong, but it seems to me that the DRM tests are carried out completely without planning and without concern for the listeners affected. Remember all those who rely on Medium Wave AM Radio: those who listen to stations which only broadcast on medium waves, those who listen in their cars where FM reception is too problematic, those who are abroad and tune in the broadcasts of their homeland, like I did when in Italy and could hear the Swedish broadcast on 1179 kHz down there every night.
There is always a problem of interference, but the situation has become chaotic as it is now. Planning and organization is necessary. Perhaps a segment of the Medium wave band or the whole Long wave band, could be allowed for DRM tests on a shared basis, where say 6 broadcasters are allowed to have tests 4 hours a day during the experimental period.
There is also a severe problem of splatter to adjacent frequencies. The BBC World Service DRM transmission on 1296 kHz strongly affects reception also on 1287 and 1305 kHz. The DRM mode causes a very broad signal, too broad for the 9 kHz segments on the LW/MW band.
I do not want to sound like a reactionary, since I fully realize the possibilities of DRM for the communication of good audio broadcasts. But my experience tells me that the coexistence between DRM and AM Radio is impossible. And I will end my letter by quoting from the American Media expert Glenn Hauser's DX Listening Digest, January 14th, 2006, in which we read:

- Here in Germany criticism on the DRM operation from Croatia on MW 594 kHz rises, since it ruins reception of co-channel Hessischer Rundfunk outside the Frankfurt area. It was definitely no DRM detestor who wrote today that they should fire up the old Siemens gear again to let the brute force of 1000 kW making the point (Kai Ludwig-D, dxld Jan 7)

And from the same source further on:

- DRM has been a pest on 1485 for at least a year. At night I cannot hear BBC Humberside any more which is SE of me by about 30 miles. Channel always dominated by DRM. I guess many broadcasters adversely affect by DRM won't complain because they want to use DRM. I'm still baffled why no one has attempted bandplanning DRM on the MW band. DRM clearly does not coexist with AM (from the AM listener's point of view) so why not assign a couple of channels as DRM only channels and let DRM transmitters congregate together. If DRM expands then add extra channels. At the moment with no bandplanning it justs makes MW a worse place to listen. Cynic mode on: Rotten noisy AM is a good reason to persuade people to switch to DRM, so could this be a deliberate policy of DRM jamming? Cynic mode off. 73s (Steve Whitt via Chris Brand, BDXC-UK via DXLD)

I think, Mrs. Konstantinova, this is more than ample proof to support my point. I am now awaiting your and the EBU's comments and future plans in this matter. I am fully aware of your limitations as an organization representing a large number of countries, and as the saying goes, no chain is stronger than its weakest links. Nevertheless, the situation caused must be met with decisive action from the EBU. And I am sure the EBU will be willing to act, to uphold the standards of listening on the Medium Wave band.

Yours sincerely, Ullmar Qvick (da DXLD nr. 14/2006)

Tags: radioascolto, radiofonia, radio, dxing.