Sound of AM back in 60s and 70s

[mgpt6]

I remember AM sounding better in the 60s and 70s. There were still plenty of 5 tube AM radios still around. Car radios pre 64-65 were tube instead of solid state. I bet Fisher and Scott tuners of the 60s had good sounding AM sections. Did not AM stations tried to proof from 100-7500 Hz freqency response back then?

 

[OKCRadioGuy]

NRSC 2.... Even with a good radio, things can't be as good due to the brick-wall limit imposed on us. It's not OK to splatter due to running a full 15kc of decent audio, but it's quite alright (in the FCC's eyes) to run digital IBUZ crap a couple channels up and down from yours. It's part of that politically correct science thing that figures into that "logic".

 

[bnesound]

I don't think the receiver had much to do with it

WLS
WCFL
CKLW
WABC

All had Kick Ass Signals and an even MORE KICK ASS SOUND. CK used tri band Dorrough compressors and sounded amazing. I used to DX when I was in high school in Metro Detroit Michigan and there were times when CFL BOOMED IN and sounded like I was sitting in downtown Chicago.

AM today sounds like shit. I don't think these yuppie engineer type give a shit anymore. Just my opinion and yuppies, don't take offense.

 

[RFGuy]

Continental 317 Doherty. Probably the best sounding Transmitter built. These newer solid state boxes are more efficent, but,,,,,,,,,,,,

 

[Tom Wells]

Continental 317 Doherty. Probably the best sounding Transmitter built. These newer solid state boxes are more efficent, but,,,,,,,,,,,,

Ooooo..can I take the liberty to finish your sentence?

,......SOME of us can hear the PWM "stairsteps", and it ain't exactly pretty.


Shortcuts are shortcuts, and unless you wanna clock your pulse widths at .5- 1 mhz, it's gonna get "grainy".
Sine wave mixing can sound OK at lower frequencies because there's no "jaggies" in the waveform.

OK, so I'm the only guy left alive apparently that has built regens, autodynes, and superhets by hand,
but it gives me perspective to critique what I hear on AM.


The receiver won't let you hear what's not there, and NRSC 2 insists that it not be there.

With proper modulation control, there's no reason for splatter OR NRSC 2.
There's simply no excuse for the way AM has been tortured into the present condition.

 

[bnesound]

Continental 317 Doherty. Probably the best sounding Transmitter built. These newer solid state boxes are more efficent, but,,,,,,,,,,,,

CFL ran the RCA BTA-50F transmitter as well

Do you know when the 317 was installed and the switch flipped to get it actually on the air? Before 1972 or after?

 

[BobOnTheJob]

I remember AM sounding better in the 60s and 70s. There were still plenty of 5 tube AM radios still around. Car radios pre 64-65 were tube instead of solid state. I bet Fisher and Scott tuners of the 60s had good sounding AM sections. Did not AM stations tried to proof from 100-7500 Hz freqency response back then?

I don't recall the FCC standards, but I remember blowing past them at WCSI, 1010 Columbus,IN in the 70's. -3db at 15khz, 0.5% distortion at 95% mod & -59db signal/noise. And I checked it every couple of weeks & tweaked the balance on the 807 audio drivers & bias on the 833A's to keep it there. On the mod monitor, it sounded brighter & cleaner than any FM of the day (and probably today). I was blessed with a DAP 310 that I modified the release times on & drove the hi-band harder than the low & mid. That was back in the days when you could drive down the road & pop goose bumps listening to your handi-work...and it was on AM.

 

[Savage]

I was at WIBG Philadelphia 1969 and 1974, and on-air at CKLW in 1973, when legendary CE Ed Buterbaugh was implementing his own home-brew multi-band discriminate processing. Wibbage used garden-variety Max Brothers (CBS Audimax-Volumax) into a 50G RCA Ampliphase by day and a 10H plate-mod RCA at night. Depending on how well the finicky Amplifuzz was getting along with the common point that day, WIBG 990 could knock the socks off most FMs heard today. CK's best-sounding rig was still on the air in '73 - a BTA-50F plate-mod monster, same transmitter as WCFL, although CKLW's was made in Montreal and was thus branded 'RCA Victor.' Of course CKLW's on-air audio was frankly unbelievable by today's standards. I've got some open-reel skimmer tapes from The Big 8 which I'll have to dub off and post samples here.

To whet your ears' appetite, here's audio right off the General Radio 1931-A mod monitor of WELM, Elmira, NY 10/1971. Tx was an RCA BTA-1R fed by the Max Twins. Station proofed flat out to 14 kHz; all tube-type equipment, including the Gatesway and the Maggie PT6-JAH on which it was recorded.

http://www.stopiboc.com/media/CHICAGO_Q67_68.mp3

I love our Nautel. But IMO this sounded even better. Be sure to listen on speakers where you can hear the bass register.

 

[mgpt6]

Savage , the clip sounded so much better than any AM you can hear today. In Boston , the only 3 stations that have any frequency range are WRKO and WEEI 50kw Entercomm and WJIB 250 watts Local owned.

My father had a 61 Ford with AM TUBE RADIO that a 2nd 6x9 rear speaker which made AM sound good in the late 60s.

 

[CKLW fan]

I was at WIBG Philadelphia 1969 and 1974, and on-air at CKLW in 1973, when legendary CE Ed Buterbaugh was implementing his own home-brew multi-band discriminate processing. ... I've got some open-reel skimmer tapes from The Big 8 which I'll have to dub off and post samples here ...

GREAT! I look forward to hearing them.

 

[bnesound]

It doesn't get much better than this

www.nethingatall.com/MamaRue.mp3

 

[wgliradio]

As time has gone on, I truly believe processing has gotten worse for AM. The old Dorroughs, Multimaxes, Urei's, Hnat Hindes and even the CL-40 were all very warm and musical. Even a well tuned up 9100 into a flat transmission system kicked ass and was loud.

Today it's all about managing bandwidth into transmitters that sound, to me, harsh.

 

[Tom Wells]

I could never afford one of the big-name boxes, but the sound Breakaway can give to AM is nothing short of
spectacular, if you're willing to run your audio through a PC.

From the Podcasting board:

Well, I'm going to try posting this aircheck on Sendspace, as Pod-O-Matic continues to downgrade files to 96k.
This is 176 MB, two hours of AM 1620, mostly at random with one or two tweaks on the fly.
The recording was just a wee bit hot, but sounds pretty good.
AM radio doesn't have to sound like a bad phone line.

1962 Bendix car tube/transistor radio audio, straight into the computer:

Not sure how long this link is good for....
http://www.sendspace.com/file/sk2wvz'>http://www.sendspace.com/file/sk2wvz

 

[Savage]

Brother Bill Gable! He was leaving The Big 8 for KHJ just prior to my arrival at CKLW.

A quick (true) war story about the Pride of Engineering at CKLW: Ed Buterbaugh and his assistants were very proud of the new studios at 1640 Ouellette Avenue in Windsor, which were only about 6 months old when I got there in May 1973. The station had a security guard 24/7 and the rear doorbell played the CKLW jingle logo in chimes, a custom flourish built by Ed and Company!

In the lobby, your feet sunk into a massive carpet laid out on the fieldstone floor. The rug was actually a custom-woven coverage map, showing the eight provinces and 26 states in The Big 8's night contour.

Out at Harrow, the late-1940s vintage BTA-50F and standby 5F gleamed like they were uncrated last week. You could eat off the painted concrete floors out there. Absolutely NO clutter. No discarded computers or junked remote or STL stuff stacked around.

Fun fact: CKLW - a single AM-only radio station - had a North American audience exceeding the entire audience for XM-Sirius today.

It was an amazing place, truly the stuff of legends.

 

[rfry]

CKLW - a single AM-only radio station - had a North American audience exceeding the entire audience for XM-Sirius today.

CKLW had/has a fine reputation and signal, no doubt.

But the 0.5 mV/m daytime coverage contour shown on their "QSL" card at least in the 1970s showed their coverage to the northwest in Michigan to be almost the equal of WJR, even though WJR radiates considerably more power in that direction than CKLW, and over a nearly identical groundwave path in that direction.

The link below leads to a comparison of these two stations according to the "marketing" departments of each.

By the FCC groundwave propagation charts, the CKLW contour shown on that QSL card is closer to 0.1 mV/m, and about 1/5 of the field intensity of WJR near Grand Rapids. That amount of decrease in field means that CKLW radiates about 4% of the power that WJR does, in that direction.

http://i62.photobucket.com/albums/h85/rfry-100/CKLW-WJR_Coverage_Compare.gif

RF (confession: WJR staff engineer in the early 1960s)

 

[Gatekeeper007]

Just like C Band satellite AM radio as been left hung out to die only because no one in the general public believes it is worth anything, don't believe me? just ask anyone around you when was the last time they listened to AM radio. You will have a very hard time finding someone who would says yes. I was checking into buying an AM station and you should see some of the looks I got at lending places (banks ect..) when they heard it was an AM station, one bank president asked me if I was crazy an AM he kept saying. Needless to say trying and explain to them about FCC rules and translators and my reasons behind the move was something else altogether. As for the sound of AM back in the day I don't think there is hardly any station on AM today to compare with back then if maybe a few.

 

[Schroedingers Cat]

Since CKLW, though it is 50 kW day and night, and operates on a designated clear channel, it has not been a skywave protected Class A/Class I station for as long as I know. Perhaps it had protection previous to the NARBA agreement that took effect when they moved to 800 in 1941. It got de facto protection in some areas of the US because there were no stations allowed to operate on 800 at night until the 1980s because Mexico had I-A status (used by XEROK). It had been duplicated in Canada for as long as that agreement had been in effect.

I would like to see that skywave map anyway. Anyone have a copy of that map?

I suspect that the contour on that map is either the 0.1 mV/m groundwave also, Rich, or perhaps they measured skywave during the critical hours. With the type of array they have, it is likely that the high angle radiation is much higher to the northwest than the horizontal groundwave radiation is.

I agree that the sound of CKLW was great in much of the 1960s and 1970s.

Ed Buterbaugh also worked at WJR (after CKLW) and WABC (forgot what years).

 

[Savage]

Well, CKLW was (and is) DA-2 with a five-tower array while WJR's a 1-A, NDA unlimited. CK had to protect, among others, Thunder Bay, Belleville, etc., so it's not surprising 760 was better towards Grand Rapids. The CKLW pattern was designed to be pretty much a local signal in Detroit, Toledo and Cleveland - and it was, back in the day. We routinely gave temp readings for the three cities.

I didn't mean to claim CKLW's coverage was the equivalent of WJR's or any other station. I was reiterating its total 12+ cume figures back in its heyday as compared with XM-Sirius (that would be the ENTIRE service's North American audience, including ALL channels.)

 

[Schroedingers Cat]

Have any of you used a Field Strength Meter to measure some of those skywaves you mentioned like WCFL? It seems I did and the skywave on by then WMVP would peak out at around 10 mV/m around SE Michigan. Anyone see much more? I had sort of roughly calibrated a Sony portable before that with a tuning meter, and I thought it was actually more than that, but I was probably standing where I was getting a strong reflection from indoor wiring.

Remember how much stronger WCFL was in SE Michigan than WLS because of WCFL's DA and slightly shorter towers than WLS?

 

[Schroedingers Cat]

I also occasionally received WCFL and WOWO skywaves on a crystal radio with an Germanium diode and a really long antenna.