30 ottobre 2008

L'SDR entra nelle radioline cinesi

Da poche settimane (grazie ad Andrea Russo per la segnalazione) i negozi cinesi di eBay offrono per una sessantina di dollari una nuova radiolina Degen. E' siglata DE1123, copre le onde corte, può riprodurre l'MP3 e registrare in WAV ed è basata su un chip Silicon Labs, l'Si473x che implementa in DSP una media frequenza digitale. E' un piccolo pezzo di SDR da 10 centimetri per 7 (e poco più di un centimetro di spessore). C'è purtroppo una piccola difficoltà di ordine commerciale. I negozi cinesi online ormai si rifiutano di spedire la merce in Italia, dove le autorità doganali respingono al mittente l'elettronica non marchiata CE. Dovete avere un indirizzo da qualche altra parte, per esempio in Svizzera. Non so se funzionano servizi di drop box americani come Borderlinx o Shopanyamericanstore che offrono di rispedire agli acquirenti non americani la merce acquistata sugli online shop USA. Ma qualcosa mi dice che i solerti doganieri tendono a bloccare soprattutto le spedizioni dall'estremo oriente.
Tornando al 1123, non deve essere una grande radio, è priva dell'SSB necessaria per ascoltare i radioamatori e non ha una presa d'antenna esterna, ma il chip Silicon Labs è interessante e fa parte di una famiglia di soluzioni che probabilmente si convertirà in ulteriori modelli di ricevitori. Assisteremo anche a una evoluzione verso le demodulazioni digitali? Sarebbe interessante. Ecco dagli Stati Uniti una prima impressione sul nuovo exploit orientale scritta da una radioappassionata, Emily Keene che sembra essere soddisfatta del rendimento in ricezione.

I got my DE1123 yesterday, In fact, as I was posting on another radio site, the amazingly attentive eBay seller, Tquchina, read my comments about waiting for the radio, actually tracked my package and sent me an email to let me know that my package was at the post office, where I was able to pick it up. First of all, I am a person who really likes radios that do a lot of things. I have a collection of those old multiband radios that try to do everything - the more bands the better! - and I LOVE them. I have one of those icom R3 radios that was created in that same spirit, and I don't care what the reviewers said about it - I really enjoy playing with the thing. That said, I was attracted to this radio because it did so many things, and I am not at all disappointed. First of all, it is a very attractive little radio that is nearly flat and would fit into almost any pocket. It comes with an English language manual which is extremely easy to follow in spite of the sometimes amusing translation. There are 3 rechargeable AAA batteries ( pre-charged and ready for action ), a carry pouch, a USB cord, earbuds, and a small wall charger that attaches to the USB cord. The radio is ergonomic heaven - it is totally intuitive, and I had no trouble trying out all the functions. I like the 1121 a lot, but it is extremely complicated to use. The 1123 doesn't do everything the 1121 can do, but what it does, it does well. The MW band is outstanding - this evening from my home right outside of NYC, I heard Charlotte NC, Cleveland, Nashville, and the sometimes elusive semi-local Hartford Connecticut without any effort. FM and MW have no bleed-through, so even the strongest stations don't cover up neighboring frequencies. The FM is fine - nice stereo sound, and quite good reception.The test stations I use, which only the "good" radios pick up here, were all there. The SW was a great surprise - lots to listen to and very little noise to detract from the clear, surprisingly steady reception. I loaded up the mp3 section of the radio with my favorite music - there was a lot of memory available, and I was able to use the Windows Media Player to transfer files to the 1123 with no problem. There was no extra software to load. The tracks sound great, and are easy to access. I recorded WAV files from the radio bands, and this was extremely easy to do - you just press a button as if it were a tape recorder.The files are a bit muddy-sounding and the manual is right - this recording works best with the volume turned way up. If your primary interest is to record music from the radio, this radio is probably not ideal since the WAV files are not high fidelity. If you want to record speech,or if you aren't fussy about the sound quality of your music, then all is well. The display has a 12 or 24 hour clock ( selectable ), the date is displayed, and there is an attractive green backlight. There is a speaker which doesn't sound too bad, but obviously, the included earphones are a major improvement. There is no SSB, there is only rudimentary push-button tuning, there is no bandwidth nor tone adjustment possible, and the mp3 files are not named, so you need to remember what number folder your files are in. The buttons that control the mp3 playback system are on a strange 3 second delay, so you need a little patience to access the files, but the process itself is very simple. My verdict - this is a handy, fun-filled entertainment center for casual radio and mp3 listening and some DXing, especially on MW and SW. As a radio-ipod hybrid, it is very satisfactory. As a radio recorder, it is efficient and easy to use, but the sound quality could be better. Am I glad I bought it? Absolutely!

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