Missing FM pilot

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Shane
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Re: Missing FM pilot

Post by Shane » Tue Nov 15, 2016 1:07 am

Good question. Used to sorta be able to see what stations had on their SCAs when I had an FM converter in my car (don't laugh..not that long ago..1982 Ford Escort I bought new with only an AM Radio and standard transmission), and I could tune up to about 1470 and hear the SCA. Very fuzzy but I could at least make out what kind of programming it was or if it was used for telemetry.

While I'm reminiscing, I remember being able to actually hear the 19 kHz pilot of stereo stations on a mono receiver. I can still hear 10 kHz but not much farther. Can't hear TV horizontal oscillators but the new TVs have no need for those, do they.
Mike Shane, CBRE
---Omaha---

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PID_Stop
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Re: Missing FM pilot

Post by PID_Stop » Tue Nov 15, 2016 2:07 pm

Shane wrote:Can't hear TV horizontal oscillators but the new TVs have no need for those, do they.
Our control rooms sound so much different nowadays: no more horizontal sweep singing out from every monitor, no more whine from the quad machines' heads, no more clicking and clunking from the ACR, and no more chattering and thunking from the film islands. Walk in nowadays, and about all you hear is the fan roar from all of the servers and OpenGear frames.

-- Jeff

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Shane
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Re: Missing FM pilot

Post by Shane » Wed Nov 16, 2016 1:34 am

As long as we're drifting, I remember when radio station studios had a peculiar smell. Not unpleasant but unique. Never figured out what it was but my best guess was the teletype machine(s). Possibly the grease used on the gears.

I should discuss this with a friend of mine here in Omaha who used to service those beasts. I used to have a model 28 in the basement ham shack I used in conjunction with a VIC-20 computer and a modem. I can't remember how exactly it worked. I didn't get into RTTY until after personal computers started to become more common. I do remember I could type live on either keyboard. The modem served as a TU, I think.
Mike Shane, CBRE
---Omaha---

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PID_Stop
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Re: Missing FM pilot

Post by PID_Stop » Wed Nov 16, 2016 12:48 pm

Shane wrote:As long as we're drifting, I remember when radio station studios had a peculiar smell. Not unpleasant but unique. Never figured out what it was but my best guess was the teletype machine(s). Possibly the grease used on the gears.
It's absolutely freaky that you should write this just a couple of days after I made the very same observation to my wife. About a week ago I brought one of the tape machines out of exile in my attic (they were boxed up when we moved nearly 20 years ago) and installed it in my study: an Ampex 440B. Cleaned it up, hooked it up, and was listening to a local pre-recorded show from 1967 when I noticed "that smell"... and it brought me back to my childhood, when Dad often took me to the station with him. It's a combination of warm motor lubricants and random stuff being heated by power resistors, solenoids, transformers, tubes, and the like, I think.

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Deep Thought
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Re: Missing FM pilot

Post by Deep Thought » Wed Nov 16, 2016 8:06 pm

"that smell"

The shellac that seals power transformers and motor windings is one of the biggest culprits. They were everywhere in the typical control room.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

ChuckG
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Re: Missing FM pilot

Post by ChuckG » Wed Nov 16, 2016 8:57 pm

PID_Stop wrote: it brought me back to my childhood, when Dad often took me to the station with him. .
You too huh? I used to go most Saturdays with my Dad from age 5-ish and up, I'd wander around and get into things while he was working.
I still maintain a station he GM'd for decades. That smell..teletypes, warm electronics, turntable and tape machine gear oil, I'm also pretty sure early solid state Gates consoles had an odor all their own. Mixed with plenty of cigarette smoke, most everyone did back then.
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RGORJANCE
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Re: "that smell"

Post by RGORJANCE » Thu Nov 17, 2016 5:22 am

OMG! That stirred a memory!

1957 - summer in Tulsa, OK at KVOO in the Philtower bldg in downtown. The A/C gets shut down on Friday evening. Working shift over weekends with the top windows open smelling dead pigeons. That was really rough.

Or the tantalizing odor of a really big dead snake in the BC-1F power supply spreading thru the rooms. BC-1F - one, snake zero.

Fossil

taylorengineer
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Re: Missing FM pilot

Post by taylorengineer » Mon Nov 21, 2016 2:35 pm

Hand wired electronics did have that unique smell. I always thought it was due to "tube warmth" heating those waxy capacitors but Deep Thought is probably correct about it being from the shellac used on the transformers/chokes.

nfr
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Re: Missing FM pilot

Post by nfr » Tue Nov 22, 2016 12:08 pm

W2XJ wrote:How did you determine that they are still running the MPX subcarrier?
I used my RTL-SDR receiver and software. It displays both the demodulated audio and discriminator output. And here is a article from Radio World on what you can do.
And just in case you were wandering what SDR I was using here is a link. The only problem with the curren version RTL-SDR is that is has 5v on the output when plugged in due to the software bias T circuit. The previous version had to have a mod for the bias which was no problem. I have on order a NooElec NESDR SMArt which does not have a bias circuit. If you want a higher end SDR look at the SDRPlay.

W2XJ
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Re: Missing FM pilot

Post by W2XJ » Mon Nov 28, 2016 10:27 pm

I figured you were either doing SDR, had a spec an or possibly just guessing. That station should really kill the MPX and take better advantage of mono.

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