Is It All Push Buttons?

[flintstone mop]

Im not ranting, but wondering if the quality of TV broadcast and AM/FM really requires such highly skilled people any more?
We view TV signals over the air and on Cable/Sat and the audio and video look uniform. Has anyone noticed any particular TV station and said "wow that TV picture looks like hell, the audio is all distorted?
Or listening to FM radio, hear one station sounding like a million dollars and another sounding like they are using processing equipment from the 60's?
It seems that most of the equipment today has pre-sets and nothing else is necessary to get a decent TV or radio signal on the air.

I know an engineer of a well known college in New Wilmington Pa. and the FM station has exceptional quality, and I asked him how he gets such amazing sound out of his FM? He just shrugged his shoulders, like "got me bub, just hooked it all together and connected the coax to the transmitter and here we are."

Now A.M. broadcast is another story. Is that a pushbutton operation too? Would they hire a consultant to get the directional array back to spec or would the contract engineer be able to handle that?


Phred

[W1GFH]

I have noticed the occasional cable TV channel with a low program audio, so someone's not minding the levels.

[W7TFO]

Indeed, the 'engineering' angle of broadcast has evolved.  Or devolved, perhaps.  

When I started at KVOY in Yuma, AZ back in '64, tubes were it, FM was still a non-entity, and things didn't go together all that easily.  A lot of impedance matching and so on were de riguer.  Along came the "low impedance output, bridging input" audio gear.  Ok, as most of it went down the balanced path.

Good tubes started disappearing from store shelves about 1978.  I started hoarding them.

Rf was still done to match driver to amp as it were.  Modulators were adjusted via bias for minimum distortion, and you used I2R to figure what you were putting into the antenna.

New AM setups have Wattmeters just like FM, and can simultaneously read reflected power too.  The overall efficiency of the new breed of AM transmitters is amazing, line-to-antennawise.  More power goes out the coax than up in heat.

Everything audio uses the AES digital format now, from the mics to computers doing playback, even to turntables for vinyl if needed.  

You can't bug it out with a buttset anymore.  Gotta' use a bit reader with a D/A converter to hear it.  That kinda sucks, but the good thing is all your ground loops are gone as 60Hz doesn't read in that format.  

The bad thing is there is still no volume level standard amongst builders of broadcast gear, and some devices are not easily adjusted.

Directional antenna systems are still usually the domain of a consulting engineer, but the complex and arcane formulas have given way to "Method of Moment" calculations relying on computers and expensive software.  One still has to run into the sticks with a field intensity meter for test readings, so a bit of fun can still be had (like explaining to cops, farmers, dogs just what you are doing on their property).

Lightning still hits towers and causes all kinds of hate & discontent, at least if they are so dumb as not to have installed static dissapators.

The undeniable area of depression is there are very few new kids emerging to take over the mantle us old guys have left.

Some new is good.  Some new is rotten.  Being in the business meant I moved along with it, sparing the emotion.  Now that it doesn't add up to a paycheck anymore (retired), it all sorta' goes along with the axiom "They are really good with the how, but don't have a friggn' clue as to the why".

73 dg

Tubes rule.

[DMOD]

TFO pretty much summarized it.

Most transmitting facilities are remotely monitored or controlled via computer links. I can dial into the transmitter and change the power or audio settings if need be, or monitor the VSWR, etc.

Most everything is digital signal links from the mike to the transmitter, even the STL.

Many audio processors come with presets that you can modifiy for your own so-called "signature" sound.

Someone with a good ear can still make a station sound good without a distorted, overcompressed audio.

Unfortunately, some of the crummy sound is caused by station managers or the bean counters wanting that fatigueing kind of sound for some of the shock-jock rock stations. I try to avoid these Turkeys, whether they be AM or FM.

TV stations transmitting facilities are usually run by a top-notch group and monitored closely with expensive monitoring equipment.

The only problem I see with the current crop of BE's is that they are whizzes when it comes to computer systems, automation, networks, etc, but lack sufficient knowledge about the RF end of things. And forget it when a tube transmitter has a problem. That's when they call the Always Cheerful Old Buzzard.

Phil - AC0OB

[DMOD]

Phred said,

Or listening to FM radio, hear one station sounding like a million dollars and another sounding like they are using processing equipment from the 60's?

I have had the studio call and say some listener called and said the audio or signal was bad.

And it was. Usually, the equipment at the studio got bumped or some whizz kid decided to mess with the AP settings.

The worst time of year is usually spring and summer with the numerous lightening strikes and tornadoes.

Phil - AC0OB

[W2VW]

Television still requires talent to produce real quality. Do most viewers notice quality? Is it worth spending the money for engineering talent? That's a good question. The quality control is almost all at the studio end now.

Transmitter facility work is a lot different now that analog TV is done. All we transmit are a 8 rows of little dots.

Forward error correction tweeks can be done more often on some systems for better SNR but that's getting easier too.

A lot of over the air quality comes from oversight of the transmitter specifications and build.

With the current money squeeze and lack of automobile spots new engineering talent is NOT being developed at a safe rate.

[WA1GFZ]

some jobs just can't be replaced with bean counters.

[K5UJ]

Some guys I know in broadcasting told me there are so many retirements on the horizon that a younger person could get into it now and in a few years have more to do than a fry cook working on Christmas day.  Traditionally, people in high demand jobs wind up making $$$.  Supply and demand.

[W8IXY]

Here at Telos/Omnia/Axia, we get numerous calls fom "engineers" who have no idea of how to adjust the audio on their stations to achieve their "signature" sound.  Its disheartening when we ask the person at the station to describe what kind of sound he wants and all he says is LOUD!  We design presets into the Omnia processors to allow these guys to get started with some pretty good sounding audio to begin with, but if you don't have a good ear to start with, and just tweak until it gets LOUD, then you can wind up transmitting square waves.  Most importantly, it takes a GOOD EAR to begin with, and a working knowledge of what the various adjustments do to the audio.

Over the past several decades, we have found combinations of "audio manipulation" that can be kind to the listeners ears, as well as achieving a loud and clean on-air sound.  However, our processors are able to be grossly maladjusted, and those can sound awful.  Plus, even if the audio processor is adjusted to a relatively "benign" set of parameters, if the transmitter/exciter is not up to par, even good audio will go bad in the transmission chain.

Regarding AM, in broadcast, many, if not most less experienced engineers don't know how much an antenna system can affect the final demodulated audio.  Directional antennas are notable for causing weird anomalies in the detected audio.  Since an antenna system can only be perfectly tuned for one frequency, and by that I mean carrier frequency, not sidebands, the actual radiated field will change as frequency is moved.  That's one reason that when you drive through nulls in a directional antenna pattern, you hear a timbre change in the audio, or even a "selective fading" sound.  I once worked on a directional AM that had a "ringing" null.  The ATU at one of the tower bases had a vacuum cap in the circuit, with a lot of current running through it, and you could hear the modulation ringing in it.  Because of the small changes in capacity due to the actual movements of the capacitors elements, it caused a small dynamic phase "modulation" of the carrier.  When the phase "moved", the changing of the parameters caused a small amplitude change in the deepest part of that null, and the envelope detector in the receiver demodulated it.  In the main lobe, you couldn't hear the ringing, but in the null, it was so pronounced that it caused a number of listeners to call in with complaints.

Broadbanding AM antenna systems is a fine art, and those of you guys who have done it on broadcast arrays know what I mean.  Plot the antenna system on a Smith chart and see what the load looks like 3, 5 or more kHz away from the carrier.  Then think of what the transmitter would load up like into a system whose VSWR would appear different for each modulating frequency.  With good design, we can usually get a system to present a decent load over 10 - 15 kHz to the transmitter.

I designed the factory presets for our Omnia ONE AM processor.  It took me several months of daily tweaking to come up with about 10 different presets for the Omnia that would work for different formats and different transmitters.  Any non linearity after the processor will deteriorate what the processor did to the audio.  If the low frequencies are rolled off in the transmitter, you will get a "tilt" of the processed wave form.  If the higher audio frequencies undergo a phase shift and/or frequency response anomaly, you will get "ringing", or the well controlled processed audio will appear to NOT be very well controlled after the phase shifts.

The transmitter needs to be as flat in response as possible between less than 10 Hz and 10 kHz to effectively allow a well processed audio signal, even if you filter the processed audio to limit response to between 100 Hz to 3kHz.  This goes for broadcast as well as ham transmitters.  Any response anomaly AFTER the audio processing will adversely affect all your efforts to control the audio you so carefully adjusted.

There is a lot more to this, as you broadcast guys know.  One of our greatest problems in our Telos/Omnia tech support area is trying to assist non audio and non tech operators to adjust their station's "sound" to what they want it to be.  If you hear a great sounding station, its probably because that station is fortunate to have an engineer with good ears, a studio/transmission system with modern equipment, and the knowledge of how to make it all "sing".

Now, having said all that....I could really get going on TV audio....but that's a whole different thing.......


Happy New Year
73  Ted   W8IXY

[W2PFY]

some jobs just can't be replaced with bean counters.

There must be at least one dreaded bean counter on here in the broadcast business, what's your take on all of this???

[KE6DF]

If you look at the EE programs at the top schools like MIT, Stanford, UC Berkeley, etc. you see very few courses in radio electronics.

And those you do see are mostly related to wireless data networks.

If you look at the research programs for MS and PhD students at these institutions, on the hardware side, the great majority of the research projects are in some way related to VLSI design and nearly all of those are digital oriented.

There are usually only a few analog courses, and a smattering of high power system courses to prepare engineers to work at electric utilities. Plus their might be a project or two in optical communications.

I believe universities consider radio a solved problem not worthy of any more research,

And if a smart young student wanted to do a PhD dissertation in something to do with radio, he probably would have trouble finding a thesis advisor and acceptable topic.

[KE6DF]

One other thought, is that is sure seems to me TV broadcasting is a dying industry.

I haven't used broadcast TV on a daily basis for at least two decades.

And I haven't used it at all even once for at least 10 years.

If broadcast TV shut down completely tomorrow I wouldn't even notice unless I read about it somewhere.

Had cable the whole time.

And broadcast radio may be dying also.

All I listen to on the radio is news talk shows while driving -- mostly for traffic reports and sometimes stock market reports.

My wife, once in a while listens to FM stations in the car, but I use music CDs.

Perhaps we are exceptions, but I don't think so.

In fact, in California, it's a rare subdivision that even lets you put a TV receiving antenna on your house -- other than a satellite dish.

Kids all seem to use iPhones and MP3 and the Internet and texting -- I don't see them listening to broadcast radio either.

I think if I were a young broadcast engineer, I'd look for another career -- you are in a dying industry.

[W1GFH]

.
Kids all seem to use iPhones and MP3 and the Internet and texting -- I don't see them listening to broadcast radio either.

I seem to recall that many people would be glued to radios during important ball games when they couldn't be home in front of the TV. Nowadays I imagine they're able to get TV coverage of games on their Smart Phones.

[W1DAN]

Hi all:

My view from a Boston TV/Radio outfit is that the tools and knowledge have indeed changed over the decades. I no longer work with analog audio and video, it is now serial digital and more importantly IP based video/audio and file transfers. HD and multi-streams of programs are driving much of our upgrades. Much of our video ends up on PC and iPhone screens.

I am now working on such thinks as video encoding techniques and their limitations, video aspect ratio conversion, storage area network setup and management, computer maintenance, LAN network setup and signal flow, fiber signal flow, Satellite RF and digital decoding, serial digital video/audio routing, Final Cut pro editing, robotic cameras, automation and yes...digital audio upmixing, downmixing and levels!

Little of what I do is "tweaking for better video/audio" as the recording, playback and signal paths generally have little effect on the signal quality.

A big concern today is video compression, that can muddy up a signal pretty fast though. This is a mind boggling set of variables in itself.

I rarely fire up a soldering iron (I did today to work on an old modem), and usually work on the block diagram signal flow of systems.

In the end, I am coming closer to IT support than traditional TV engineering. Dave is involved with TV transmission such as 8VSB, multiplexing of signals/data, and TV RF performance. I am doing a little of this as well. Try to read the ATSC standards sometime. It ain't a single analog radio console with turntables feeding an AM DA system anymore. Wish it were as my job would be easy.

People are not going into broadcast as the industry is mature and downsizing. Workers can usually do better in other industries. We are trying to do more with fewer people.

As a hobby I follow audio processing developments (say from Omnia and Orban)...generally live the analog past with it's tradeoffs.

Have a great 2010!!

73,
Dan
W1DAN