HD 2

[Savage]

Yes - note the now-being-touted "nationalization" of CBS Radio stations via HD-2 subs. 

Setting aside for a moment the obvious truism that irrespective of programming, few of the HD-2s are going to be heard because of the essentially nonexistent audience for HD-FM, particularly the side channels:

This is corporate radio's notion of providing diverse formats: take your country station in Houston, for example, and plunk it on an HD-2 in Hartford.  Take an LA dance hits format and export it to a co-owned Seattle HD-2.  And so forth.  Zero investment, zero effort = zero results.

Great.  Now THAT's localism and variety that's sure to bring those listeners on board with HD.

[rbrucecarter5]

"Don't force feed me the music you want to play, I know what I like and what I don't." Then you will love "Jack" - Playing what we want." 

Getting back on topic, I thought that HD would be similar to DX - more variety from different sources. But with a few exceptions it is still more of the same - yet another flavor of Rock.

Actually Bob-FM from Austin comes in well enough it merits a preset in Houston.  After the oldies fiasco here, I scramble to find any songs on broadcast radio I like.  Between Bob-FM, a couple of things in Beaumont, a small town station in Liberty, and a couple of AM's, it is still possible to get oldies in Houston.  But satellite is much easier, and streaming will give an even wider variety of stations.  As for CCM - don't even get me started - so much for the local garbage when I can stream in the car.  REAL CCM / Christian rock for a change instead of Jesus is my girlfriend PW rubbish.

[Collector]

My understanding is that the intended power boost isn't 10 or 6 db.  It's going from 1% of current (analog) transmitter power being inserted into the HD carrier to 6% of the transmitter power being diverted.  The NAB guys had wanted 10% of transmitter power but the NPR engineers made too strong of a case for protecting the frequencies down in the public radio sector.  Going from using 1% of your transmitters' power to using 6% or 10% should be more than a 10 db gain I think.

[RadeoEngineer]

My understanding is that the intended power boost isn't 10 or 6 db.  It's going from 1% of current (analog) transmitter power being inserted into the HD carrier to 6% of the transmitter power being diverted.  The NAB guys had wanted 10% of transmitter power but the NPR engineers made too strong of a case for protecting the frequencies down in the public radio sector.  Going from using 1% of your transmitters' power to using 6% or 10% should be more than a 10 db gain I think.

Let's say you're currently transmitting analog at 1000 watts.  That would give you a 10 watt HD power, or 1% of your analog power or -20 dBc (deciBells below carrier).  Now the FCC says you can raise that power by 10 dBc.  Your new HD power becomes 100 watts or 10% of your analog power.  This will get confusing if you don't understand dB.  If the FCC says you can only raise power by 6 dBc, then your new HD power becomes 40 watts or 4% of your analog power.  % and dBc don't work the same way.  % is linear and dBc is, well, not.

[radioskeptic]

The Bel is logarithmic unit.  One Bel represents a factor of 10, so that +1 Bel means 10 times the power, and -1 Bel means one-tenth the power. And since it takes 10 decibels (10 dB) to equal 1 Bel, while an increase of 10 dB means 10 times the power, while a decrease of 10 dB means one-tenth the power.  Logical, isn’t it?

Now this also means that an increase of 1 dB means an increase in poser by a factor of the 10th root of 10 (10^0.1), which is approximately 1.2589254.  And increase of 3dB is an increase by a factor of 10^0.3, or approximately 1.9952623.

For general purposes, we can round those numbers off to 1.25 and 2 respectively – or to 0.8 and 0.5 when there’s a minus sign in front of the number of decibels.

And when we add decibels, we have to multiply the factors they represent, so that 6 dB, which is 3 dB + 3 dB, gives us power factor of 4, which is, of course, 2 times 2!

[RadeoEngineer]

The Bel is logarithmic unit.  One Bel represents a factor of 10, so that +1 Bel means 10 times the power, and -1 Bel means one-tenth the power. And since it takes 10 decibels (10 dB) to equal 1 Bel, while an increase of 10 dB means 10 times the power, while a decrease of 10 dB means one-tenth the power.  Logical, isn’t it?

Now this also means that an increase of 1 dB means an increase in poser by a factor of the 10th root of 10 (10^0.1), which is approximately 1.2589254.  And increase of 3dB is an increase by a factor of 10^0.3, or approximately 1.9952623.

For general purposes, we can round those numbers off to 1.25 and 2 respectively – or to 0.8 and 0.5 when there’s a minus sign in front of the number of decibels.

And when we add decibels, we have to multiply the factors they represent, so that 6 dB, which is 3 dB + 3 dB, gives us power factor of 4, which is, of course, 2 times 2!

Yeah.  I was trying to keep it simple brudda.

[KB1OKL]

Now I remember why I keep forgetting how decibels work.