Re: [mwdx] Re: [HCDX] A question about the power of European tx'ers

[Jorma Mantyla <jmantyla@xxxxxxxxxx>]

The reason for different audio sound is that radio stations in
North America use heavy audio compression.  In Europe that is
restricted by ITU because it generates splash that may cause
interference to nearby radio stations within large frequency
range (+- 30 or even 40 kHz from stn original frequency).
You can find this phenomenon on FM, too, but is most clearly
heard on AM.
Because of heavy audio compression (30 dB or even more) the
sound of a radio station sounds louder.  Commercial radio
stations do this as they believe listeners favour and find
easier radio stations with loud audio signal.  By doing this
they try to compensate low power.
You can hear the difference if you listen locally to a 1 kW 
North American stn and compare it locally with same antenna 
with a 100 kW European stn.
The S-meter in the case of a North American stn may show 
weaker signal than the 100 kW European but the audio
sounds louder.
Fortunately it is so!  The result could be terrific with splash
around the MW-band here in Europe if 100-1000 kW stn's use the same 
audio compression as in North America.
By limiting compression ITU tries to limit the disadvantages
of European megawatt transmitters.
The audio of European low compression radio stations
is more realistic.  Compression actually is unnatural as
it decreases the dynamic range of sound.  This is important
especially if you listen to classical music.  But this is not
often broadcast on AM, thus AM-stations use more and more
compression around the world.
For dx'ers compression is good.  You can hear clear
audio despite weak slong-distance signal.  In case of low
compression you need stronger signal to understand what
you hear.

Jorma Mantyla
Kangasala, Finland

On Tue, 17 Jun 2003, Aurel Chiochiu wrote:

> Thanks to all of you who replied !
> 
> In Romania, the anti-Ceausescu messages were transmitted over SW, via RFL
> (Radio Europa Liberã), not over MW, only on SW wich was jammed by the way (I
> think the tx site of the RFL jammers were in Bod, in the same site that host
> the 1200 kW LW tx'er on 153 kHz that is used nowadays by Radio România
> Actualitãti). Radio Europa Liberã was the only foreign station broadcasting
> to Romania and it was 100% anti-communist programming and all on SW. If they
> had done this on MW, because of the lower frequency and a higher amount of
> groundwave (and somewhat less skywave obviously) Ceasusescu would have put
> local tx'er on the same channels as RFL and the listening would have become
> impossible.
> 
> Another thing: I'm still stumped that despite some MW tx'ers are using way
> over 1 megawatt, European DX'ers are getting more deep-South American DX
> than those in North America (here a coastal location like Cappahayden, NF,
> Yarmouth, NS or Cape Cod, MA or east-coast Florida is required to get deep
> into South America on MW). For exemple there are several powerfull
> transmitters on 1575, but Radio Familia de Maule from CHile still can be
> heard on 1570 (at least in Scandinavia).
> 
> I know that all the Beverages antenna used in Lapland help, but a DX'er
> using a Beverage antenna in the midwest have problems picking up Central
> Americans. Might this be because European stations are very directionnal or
> what ? I have heard from someone that was only a few hundreds of kilometers
> from Finland-963 that reception of this station was very poor and they might
> be highly directionnal.
> 
> I also wonder (even with those phasers, the power is enormous at 1.3 MW) how
> can you log TAs like CKEC when Norway is next door on 1314.
> 
> As for those wondering about the concrete issue... well, in Romania over 90%
> of the houses have a reinforced concrete structure, because each few years
> there are big earthquakes there, so that was the reason, in my opinion, why
> most Romanian stations use over 100 kW, like Craiova 558 use 600 kW and when
> I lived in an appartment at the 4th floor on a concrete-steel frame
> building, using just a very unsensitive Emerson AM/FM walk-man wich had poor
> audio on AM to makes things worse (I was in Bucharest, about 200 kilometers
> away from Craiova; the same distance as Ottawa from here in Mtl.), but the
> reception was fair and very listenable at high noon in August via pure
> groundwave.
> 
> When I was the last summer in a hospital, I could barely detect (without
> understanding nothing) WVMT out of Burlington, VT (on 620) using the same
> weak Emerson AM/FM walkman and the window where I was faced directly to the
> south. They also use 5 kW directionnal north-south as to avoid QRM'ing WZON
> east of them, in Maine. + Burlington is about 125 kilometers from Mtl. while
> Craiova was 1.75 times further. But still no way I could hear them, because
> of the concrete structure; but in Bucharest, Radio Craiova could still be
> heard on 558 with a very listenable signal and only the ceilings strucutre
> was in mettalic concrete, but even the walls were in concrete in that
> appartment.
> 
> I would like to hear your comments on this concrete-super-powerfull Euro
> tx'ers issue as well as the SW versus MW propaganda thing.
> 
> Well, a very good evening to all of you (it's late in the evening in Europe
> right now !).
> 
> 73 and good DX,
> Bogdan
> 
> 
> 
> 
> 
> 
> 
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