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Archive for September, 2008

Radio Goes Digital!

[Imported from my older radio programming blog, first published in 06/05/2004]

An unexamined life is not worth living. — Aristotle

I love listening to radio mosly when I’m out of Dhaka. Hmm, where haven’t I gone? Nilphamari*, Bandarban*? Glad you asked. Yes, that’s the beauty of my job … Hell, no! I love my job, cause it allows me reaching out almost all over Bangladesh and beyond and those cool expierences money can’t buy. Wherever I get to, my Sony ICF 7600 makes my day.

I’m still into shortwave listening for some beautiful stations covering our planet … mostly, Radio Netherlands, Deutsche Welle, CBC and BBC! Well, (sigh) I’ve tried those DAB (digital audio broadcasting) and DRM ( Digital Radio Mondiale) in Britain, Frankfurt and Singapore regions. Well, for the techies, you’d say, there is no point falling back and listen to FM radio. The difference between DAB and FM is what would be in AM and FM. I used to listen 3C, Continuous Cool Country, country music station in North East England and JK pop in Singapore (MediaCorp Radio, sg). They did a wonderful job connecting Nashville songs from there.

Software based DRM reciever …

However, DAB tuners are expensive, but if want to know what DAB can be at its best, tune into BBC Radio 3 where you won’t be able to tell the difference between a broadcast and a CD! True, guys!

And for DRM, … not those junk words like windows mediaplayer’s digital right management :-), when one considers that the DRM signal is on shortwave and uses the same radio spectrum as a conventional AM signal, then the results are really impressive. It does whole lot of compression in comparison to DAB (Eureka 147) and still sounds good. I must thank them for making a non-proprietary system for a universal digital system for the AM broadcasting bands below 30 MHz — shortwave, mediumwave and longwave.

IF Mixer, modified …

It has got a software radio project which will have the radio ready to provide a suitable output to your PC for decoding DRM. Like, if you have a old Sony ICF-7600 series short wave reciever like me, the receiver has a PLL synthesized tuning basis, but largely relies on analog circuitry for AM reception, using double conversion with IF1 = 55.845 MHz and IF2 = 450 kHz. So, you need to integrate the widely used DRM down mixer manufactured by Sat Schneider.

Yes, it is possible to install the DRM mixer circuit, hook up an output jack and install an external antenna connector and that 12 kHz DRM output signal will be hooked to the “line out” jack socket. The original audio output signal will be disconnected, as it is not of much use anyway. The signal is far below specs for “line out”. You will get all the modification instruction in this link. See … what are they saying about shortwave and reaching global? The beauty of shortwave! Period.

 

The world’s leading international broadcasters are part of DRM, so the early focus will be on HF bands. The great thing about the HF bands is that, potentially, the transmissions can go worldwide. Broadcasters such as BBC World Service, Radio Netherlands, Deutsche Welle, and Radio Canada International/CBC are already making pilot transmissions. National broadcasters will follow on the MF and LF bands.

DRM medium-wave and long-wave test and development networks already exist in Berlin and Halle, Germany and Dorset, UK.We do have the capability to respond to demand, if there is a lot of interest from a particular county, we can put on test transmissions for that country (that’s the beauty of short-wave!)This is why it is useful to us if you register on this site, so we can plan which areas of the world we need to make test transmissions to.

Well, I’ll be back with loads of detail on digital radio transmission pretty soon, specially, DRM on shortwave. Yes, I love shortwave. Until then happy DRMing!

* They are the farthest cities of Bangladesh

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The Impossible, Faith is Paramount

Yes, my class would always start from 7:00 AM and getting there would force me starting almost at 6:00. The traffic wasn’t there at all, cause it was a suburb city of down south of Georgia. Pretty peaceful, I still miss that place. During my ride, Augusta’s WBBQ FM station used to make my days. One day, the song started, it was almost dawn, I had to pull over the car.

Come again?

True! I didn’t want to miss the essence of whole song because of the natural car noise. [It was a $800 car!] It took my breath away. Its wonderful ballad took me to the point to cry out loud.

My dad chased monsters from the dark
He checked underneath my bed
He could lift me with one arm
Way up over top his head
He could loosen rusty bolts
With a quick turn of his wrench
He pulled splinters from his hand
Never even flinched
In thirteen years I’d never seen him cry
But the day that grandpa died, I realized

I was talking about the track “The Impossible”, and sounded so great even when I had not slept at all the night before for my class preparation. This one reminds me impossible dreams that I have always dreamt off.

Later I found out that the Academy of Country Music named Joe Nichols its top New Male Vocalist, he garnered three Grammy nominations, and Billboard declared “The Impossible” the tenth most-played song in 2003. It even got tremendous airplay from non-country radio station. The video was superb too. CMT did cover it well.

The song has a deeper meaning. Just because something isn’t easy or has never been accomplished doesn’t mean it’s impossible. The song also signaled that fear and pessimism don’t get you very far in life. It also quoted that you have to take that feared step and dare to risk it all. When it comes to success, faith is paramount. Life has its own way of interpreting things, impossible thing happens.

Unsinkable ships, sink
Unbreakable walls, break
Sometimes the things you think would never happen
Happens just like that
Unbend-able steel, bends
If the fury of the wind is unstoppable
I’ve learned to never underestimate
The impossible

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Basic Turns 40!

[Imported from my older programming blog, first published in 6/7/2004]

Make your life extraordinary. — Dead Poets Society

Remember BASIC? Recently, Computer world had talked about Basic, originally an acronym for Beginners’ All-purpose Symbolic Instruction Code, which turned at the age 40. Good heavens! I still remember those commodore days (yes, it was my friend’s C64, he was a games fanatic! Still he is!) … doing some games programming using GOTO, PRINT, LIST, SAVE, RUN, END etc.

I used to get perplex with those “SYNTAX ERROR” prompts practicing with a basic manual supplied with his commodore. BASIC’s GOTO’s were somehow easy to relate to when I was a computer newbie. It is just like “go to step X” or “see page X” in those sound and graphics programming. Of course, getting hooked on BASIC was not a good outcome. We used to fight all day! What was the year then? 1984-86? My friend texted me back without replying my query.

The commodore manual has some exciting programming samples like turning C64’s keyboard into synthesizer, creating chopper’s sound … etc, etc! It was really a cool machine! “Hmm, was BASIC easy?” I hear you saying that. Okay, here is a sample gw-basic code which produce the blast-off sound of a rocket! Well, you don’t have to be a rocket scientist for coding this silly 4 lines!

10 REM ****** Rocket Blastoff ********
20 FOR FREQ% = 50 TO 1150 STEP 50
30 SOUND FREQ%,.5
40 NEXT FREQ%
50 END

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[Imported from my older Antenna blog, from the time when I had been an antenna freak]

6/15/2004
Democratic Republic of Congo

Somewhere, something incredible is waiting to be known. –Carl Sagan

I have been living in Africa for a while and latched my LNB[F]* (dual polarity, V/H and FTA receiver) for different birds like PanAmsat, Arabsat, Afristar, Thaicom, Asiasat and other satellites. So far, I didn’t have any problem with vertical and horizontal polarity until one day I thought of reaching Canal Algerie for watching Euro 2004 game in NSS-7 satellite (22 degree West). Horrifically, I found the frequency to be Right polarized.

Don’t fall flat, yes, you heard me right. I was little perplexed, how on earth my LNBF can be tuned for “Right” polarized signal? Luckily, my LNBF has a “dielectric plate” into the throat of the feed-horn which I didn’t use so far.

After googling [with an inmarsat receiver] for a while I figured out that it is possible to receive right polarised signal in negligible loss with that dielectric plate placed 45 degree to the normal. A circular (L/R) signal has a horizontal and a vertical linear component because it is not polarized in a linear manner. A normal (linear-polarisation) LNB will pick the circular signals up since the circular-polarisation can actually be seen as having both vertical and horizontal linear components. Well, some says, half of the signal (3 db) loss will occur. And most circularly polarised signals are C-band transmissions which tend to be much weaker anyway (Ku-band are by comparison usually stronger, more focused beams, mostly the off-set, not the primary focused antenna). For that reason I needed a bigger dish. Well while describing the circular polarization Colin Blanshard Withers discussed an interesting story. By then, 4 games of Euro 2004 slipped by.

These are best thought of using the rope analogy. If you tie a 10m thin rope to a wall, hold the rope slightly taut and then move your hand up and down you will see vertical waves moving along the rope towards the wall (Vertical Polarity), if you move your hand from side to side you will see horizontal waves moving along the rope towards the wall (horizontal polarity), if you move your hand in a circular or corkscrew manner, and do this in a clockwise fashion, then you will see a spiral wave move along the rope towards the wall (Right-Hand Circular Polarity), and moving your hand anticlockwise will result in the opposite (Left-Hand Circular Polarity).

Listening to: (You want to) Make A Memory – Bon Jovi [repeat forever mode].
Reading: TI-89 Graphing Calculator for Dummies.

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Waiting for a Star to Fall

I know you wouldn’t agree to what other things I write here, but I bet you have always loved this movie.

Mary was really adorable when these three single men were raising her. The acts of parenting were really enjoyable as they didn’t have clues on parenting, what to talk about feeding her. I have always loved Tom Selleck and Ted Danson’s movies.

Oh, right! I haven’t talked about the movie.

Three Men and a Little Lady” you shrugged. My bad! It happens all the time.

The movie was fantastic, but my love for the movie was for a beautiful soundtrack as featured during the final wedding scene and end credits.

Like lot of other hits, this song too was originally written for Whitney Houston but was rejected as unsuitable for her.

Thanks, she rejected that. I really do.

Waiting for a Star to Fall” reached the top 5 in the US and went #1 in Europe”; it still rings the bell to all the music lover. George Merrill and Shannon Rubicam named themselves as “Boy Meets Girl” are from Seattle. I have got soft corner for that place as “When Harry Met Sally” was based on this city. “Wonderground” a quiet, charming album released in 2003 and I have it, dealt with their past as soft rock hitmakers, the dissolution of their marriage, and the state of life in the present.

Why do people break up?

It still takes me back in time when life was lot easier. While writing a flood of adolescent memories came rushing back. Twelve years, time really flies.

I hear your name whispered on the wind
It’s a sound that makes me cry
I hear a song blow again and again
Through my mind and I don’t know why
I wish I didn’t feel so strong about you
Like happiness and love revolve around you

I am amazed with their new site, it has a great face lift. You will love it.

 

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