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Transmitters Then and Now

V

VeteranPD

When I started out in radio, I was a college student and it was 1972. I visited a lot of transmitter sites and met some really kind engineers who were always willing to share of their time and knowledge.

I remember transmitters that took up a good part of the transmitter room..an RCA 5DX than ran the length of a wall to generate 5kw. Now transmitters are the size of a file cabinet.
The transmitters of that time had names like RCA, Collins, GE, Westinghouse,Gates..hard to believe so many of them are gone. For processing most stations had Audimax, Volumax and later a Dorrough if you were state of the art.

The question is, while todays transmitters are a lot more efficient, run cool and make a smaller footprint, do they really sound better? Perhaps I'm just nostalgic, but IMHO nothing sounds like some of the AMs that I grew up with like WNEW or WOWO both of which ran big Westinghouse 50HGs. Did you ever think you'd see a day when transmitters were basically a PC hooked up to an RF amp?
 
To answer your last question...I gave up trying to predict the future long ago. A PC hooked to a transmitter? That-in a nutshell-is what took the fun & magic out of radio.

As far as the big RCA's...I was there the day that WKRC 550 Cincinnati switched off their old RCA in 1975 and turned on their (at the time) new pair of Harris MW5A's. It was like switching from AM to FM. The cleaner sound & high end enhancement were that impressive. We've come a long way since MW-5A's. And that was with a Solid Statesman AM Limiter!

That said, I know what your talking about in terms of the way AM used to sound when those impressive beasts ruled the airwaves. That was a day with wider bandwidth AM radios, no NRSC 10khz limit, no computer noise and no IBOC hiss. AM's potential was able to get through to the listener back then. It's my belief that if we had BE AM-5A's & Omnia 5EX HD+AM's in that day, the sound from those vintage radios would have been truly breathtaking. For now, enjoy the next few weeks or months until AM IBOC is permitted at night. I hate to say it, but I fear these are the good old days for AM...
 
I agree with Bob...and blame regulations and cheap radios, not the transmitters...
started in AM in 1958...those were the days...not a transistor in the whole radio station! Thanks JBI ( and the old Collins board was hot to the touch,,...but sounded terrific>)
 
That brings me to my next question: WHAT IS THE TRANSMIITER OF CHOICE TODAY?
I would say the major contenders are Harris and Nautel. State your choices for AM or FM. What is the cost of a new transmitter today in the 50Kw range and who is the most expensive. Thanks!
 
The old GE, Collins and RCA plate modulated transmitters has a signature sound to them best described as “warm”. This was not your imagination but a reality. They were very well engineered machines and all of the transformer iron contributed to that “warm” sound by generating linear distortion that is musical in nature. By todays standards, they were costly to maintain from a power consumption and maintenance standpoint. Newer model Am transmitters are solid-state or no tubes to wear out. Older tube transmitters were rated at 30% continuous where today they are rated at 100%. This means they will modulate more densely with IM distortion and transient distortion numbers less than 1.0% at 100% modulation, they are much louder and cleaner in sound and spectrum.

A transmitter choice today comes down to a matter of preference but if you stay with the top three, you can’t go wrong for the most part. Not in any order, BE, Continental and Harris for FM. They all do a very good job and stand behind their products and I don’t think you will find much difference in the prices if you compare apples and apples.

As far as AM low to mid power, BE offers a very good product that is inexpensive to operate and maintain and has superb reliability. 1 kw for about $10k and 5 kw for about $30k. The BE 50kw product has good promise but needs more time to work out bugs. I have been working with two of them in the area and will say that they are coming along and I won’t go any further than that at this time. Right now, you can’t go wrong with Harris or Nautel at the 50kw power level. Pros and cons are a wash and I operate a Harris DX-50 and 3DX-50 at the same location. There is also a BE AM5 that is a deep back up.
These are seasoned well designed machines that are very reliable and sound good. I think the cost has gone down on the 50kw’s. The Harris DX-50 was about $165k in 1998 and 3DX50 was about $150k in 2000. I think you can buy a BE for about $145k and the other two will meet that price if you press them.

w/
 
Watt, that 'warm' sound is intermodulation distorition. The whole beauty of the 828 and to a degree the MW- series is/was, without the big iron they were capable of a very low intermod spec. The 820 was as good as anyone's plate modulated, and it was capable of about 4% using SMPTE at 95 percent modulation. And they were nice sounding.
Best 'nostalgia' plant I've seen was the 50 Westinghouse at KYKK some years ago. 300 degree meter movements, took up a wall, cooling pond out back. And they had an old Fairbanks - Morse Diesel generator in the basement with an ope frame generator. The new stuff is kinda sterile by comparison. It specs better and sounds better but even FM radio quality is dropping like a stone. And, without a rework station for surface mount components, you can't repair a lot of the stuff we're seeing.
Interestingly, Continental has shipped a pair of water - cooled FMs recently (!) and has another on the factory floor ready to go. Allows them to make 30KW of IBOC/analog combined out of the three bay boxes. We've come full circle, looks as if. God forbid we should see a HT 30/35 with a radiator on the back of the thing. Maybe I could at least make a decent cup of coffee off it.
 
HT 30/35 with a radiator on the back. Ah! Vapor phase cooling concept makes a return.
BTA 1-M sounded good too….. I have a couple 833A’s just to remind me. In summary,
I prefer the bland, boring current surface mount topology. Those old beast could be rather tempestious at the worst possible times.
w/
 
I don't know if it's still in service, but when I left WMID, the RCA BTA-1 had grease stains on top where the jocks would keep their pizza and strombolis warm. I miss the "singing" mod plate xfrmr's.

I listen to airchecks of WABC New York from the '60's, and that wonderful bassline that the plates would put into the ether. That went with efficiency.
 
Nautel makes a darn good transmitter for AM and their FM stuff is great too. Continental FMs are awsome. There's not much wrong with Harris as far as the equipment is conserned. (it's just the fun-and-games with the company that produces it) I hear their new AM transmitters are pretty decent.

I had a 50k AM Nautel (Ampfet 50). It wasn't without failure, but considering it's a 50k box and mid-80s vintage (early design) it was a trooper. I hear the new Nautel AMs are even better. Nautel has some of the nicest tech support people you'll ever talk to. For over a decade I've NEVER had a incompetent or rude person from Nautel. That's a pretty decent record IMHO. Contiental is great too in support. I've had limited contact with BE, but they've always treated me right when I've had to call them.
 
OKCRadioGuy said:
Nautel makes a darn good transmitter for AM and their FM stuff is great too. Continental FMs are awsome. There's not much wrong with Harris as far as the equipment is conserned. (it's just the fun-and-games with the company that produces it) I hear their new AM transmitters are pretty decent.

I had a 50k AM Nautel (Ampfet 50). It wasn't without failure, but considering it's a 50k box and mid-80s vintage (early design) it was a trooper. I hear the new Nautel AMs are even better. Nautel has some of the nicest tech support people you'll ever talk to. For over a decade I've NEVER had a incompetent or rude person from Nautel. That's a pretty decent record IMHO. Contiental is great too in support. I've had limited contact with BE, but they've always treated me right when I've had to call them.
Click to expand...

I've recently had a Nautel V10 FM come into the fold. The only other Nautel I've had to work with was an Ampfet 1KW, which was also a mid 1980's model. It seems that the one time I had to call tech support after hours, no one called back until the next day. This has been some time ago & I have slept since then. What can you tell me about their tech support? In particaular, being able to be put through to a live person in the service dept without waiting for a call back?

My experience with BE has been superb...right down to the service tech giving me his personal cell phone number on one occasion.
 
If your looking for a small size transmitter Box then its a BE transmitter.
If you want reliability . I would take a Harris box anyday. Nautels fit this catagory with the Harris.
If you want 99% reliability in any Condition you must buy a Tube transmitter.
 
I've had plants with BE beside Harris, the BE runs when the Harris won't. Got a plant with a Continental beside a Harris, the Continental runs when the Harris won't. The Harris stuff shows improvement, but it's still got quite a long ways to go. Contrast and compare the relative complexities of the Z series Harris transistor box with the BE 703 series. Both are 16 module RF generators, you can argue the combiner topology either way, and they use pretty much the same devices in the modules, but the Harris control chain is substantially more complex to achieve the same result. Likewise, contrast and compare the HT-30/35 with the 816R family of tube boxes (Or the 30T BE). Same tube, quarter wave cavities on the Harris and Continental. But again, the Harris control chain is incredibly complex and overdone to achieve the same result. Up the parts count and complexity, and you up the MTBF.
I've not found the current models to be any more or less reliable, tube vs transistor radios. There's enough solid state control parts in tube radios that the same things which do dirt to the transistors (Surges, poor grounding, bad power) tend to take the tube boxes down as well.
Or, put differently, I find the Continental and BE substantially more reliable.
 
I'm still waiting for someone to make a solid state AM or FM that's as reliable as a 37 year old CCA FM tube rig.
 
amfmsw said:
I don't know if it's still in service, but when I left WMID, the RCA BTA-1 had grease stains on top where the jocks would keep their pizza and strombolis warm. I miss the "singing" mod plate xfrmr's.

I listen to airchecks of WABC New York from the '60's, and that wonderful bassline that the plates would put into the ether. That went with efficiency.
Click to expand...

The secret to WABC's loud-and-proud sound in the '60s wasn't so much the transmitter employed, but rather the careful attention that was paid in making its antenna load look like a giant resistor. This was before it became fashionable to broadband antenna systems, and it made a huge difference.
 
A couple of months ago I installed an Orban 9400 at an AM utilizing an MW-1A as the main transmitter with an RCA BTA-1R as a backup. I was instructed by the GM to 'maximize" the audio. In other words, make it sound like crap, albeit loud. I was instructed to feed the RCA the with same processor settings as the MW-1A. No way was I going to do that, but I didn't tell him that. The station had been using an Inovonics processor and this is what I had intended to use with the RCA.

On the day of setup, I called the GM and told him that I would be installing the 9400 that day and to expect to hear brief audio dropouts, etc. Before continuing with the story, let me say that the 9400 is a very nice box when used in moderation, but of course this is not the way I was instructed to set it up.

After getting the MW-1A set up with the 9400, I happened to notice a set of old CRL's sitting on a shelf. I then started on plan 'B'. After checking out the CRL's and finding them to be in good working condition, I installed them in the rack, switched over to the RCA and was listening to the RCA/CRL setup when my cell phone rang. It was the GM who instructed me to tweak no further. He informed me that the station had never sounded better. ;D I then backed way off on the 9400 processing and returned the MW-!A to air and smiled all the way home.
 
Radioceo said:
A couple of months ago I installed an Orban 9400 at an AM utilizing an MW-1A as the main transmitter with an RCA BTA-1R as a backup. I was instructed by the GM to 'maximize" the audio. In other words, make it sound like crap, albeit loud. I was instructed to feed the RCA the with same processor settings as the MW-1A. No way was I going to do that, but I didn't tell him that. The station had been using an Inovonics processor and this is what I had intended to use with the RCA.

On the day of setup, I called the GM and told him that I would be installing the 9400 that day and to expect to hear brief audio dropouts, etc. Before continuing with the story, let me say that the 9400 is a very nice box when used in moderation, but of course this is not the way I was instructed to set it up.

After getting the MW-1A set up with the 9400, I happened to notice a set of old CRL's sitting on a shelf. I then started on plan 'B'. After checking out the CRL's and finding them to be in good working condition, I installed them in the rack, switched over to the RCA and was listening to the RCA/CRL setup when my cell phone rang. It was the GM who instructed me to tweak no further. He informed me that the station had never sounded better. ;D I then backed way off on the 9400 processing and returned the MW-!A to air and smiled all the way home.
Click to expand...

This reminds me of a very common printing pressman's trick.
When the customer comes in for a color OK on a print job, there is much adjustment, discussion and fiddling to try to satisfy
the customer, because it is often difficult to print something that matches the "proof" provided.

When this becomes a long drawn out process, with only the tiniest mismatch left, but the customer still unsatisfied,
the pressman, getting frustrated, says, "wait here at the color desk just a minute, I'm going to try something else."
He goes back around to the backside of the press, where he is presumably adjusting something, but does nothing.
He then comes back after 2 minutes, and tells the customer that the sheets should look better now.
They pull a sheet, the customer looks at it critically, and then gives the OK.
Then they tell the pressman he sure knows his business.
"makes and adjustment
 
Great article in current RW on the CCA 1000 series. This was a dependable, great sounding, although quirky XMTR. It's the one I cut my teeth on at WPAZ in 1972. I believe they still use it.
 
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