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The Old FM Band 42-50mhz

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Deleted User 14803

The Old FM Band 42-50mhz

Post by Deleted User 14803 » Wed Dec 19, 2018 8:42 pm

Any of you radio geeks know why the first FM Band 42-50 MHZ was never fully utilized , I know there were experimental stations for a short while but what really happened? I know Detroit had a few FM stations on that band as well. WWJ and WXYZ and maybe a couple more any ideas on how it all went down.



CK-722
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Re: The Old FM Band 42-50mhz

Post by CK-722 » Wed Dec 19, 2018 9:02 pm

I'd say that the biggest reason it was not utilized is that RCA NBC was trying to bump it off so it wouldn't compete with AM. Then WW II began and they had an excuse to move slowly. Then WW II ended, and they found an excuse to move it to 88-108 MHz where Sporadic E didn't cause interference (ha ha). But the catch was, your 42-50 MHz radio was then obsolete. You had to buy a whole new radio. Finally, it slowly achieved parity to AM in the ~1970s. Even the non simulcast rules slowed FM with its creation of laissez faire programming chaos, which was preferred by nonconventional audiences, not the mainstream. The simulcasts provided a way to hear the same AM programming on FM under adverse conditions, in steel buildings, during electrical storms, and on crowded AM frequencies. Gotta stop that, they might stop listening to the clear channel giants. Ever see the picture of the 2 Bay dipole turnstile transmitting antenna for W45D 44.5 (now WXYT-FM 97.1) on top of the Penobscot Building? Was that picture in "Living On Air", when they hid Don DeGroot up there for a few years?
Last edited by CK-722 on Wed Dec 19, 2018 9:34 pm, edited 3 times in total.


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Deleted User 14803

Re: The Old FM Band 42-50mhz

Post by Deleted User 14803 » Wed Dec 19, 2018 9:10 pm

Could they use that today for a possible second FM Band, and utilize it for AM to move to 42 MHz.



CK-722
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Re: The Old FM Band 42-50mhz

Post by CK-722 » Wed Dec 19, 2018 9:32 pm

The short answer is no. It has been proposed in various forms, some by Larry Tighe from WRNJ Radio New Jersey, but shot down each time. One time they proposed using the 50-54 MHz 6 Meter Ham Band, which of course was also shot down.

Here's the W45D 44.5 MHz Antenna.

https://spaceintruderdetector.tumblr.co ... -penobscot

How to decipher Old FM Band call letters and frequency. Take the two digit number, put a decimal point in the middle, and put a 4 before it, and put MHz after it. The W designates the rough location. The D indicates either 1) the fourth station licensed on the frequency or 2) Detroit.


Is THAT where they got the idea for the 486-SX?

Same (x, y, z), different (t)

Your bullet missed my trial balloon.

RTN Price. Not guaranteed. As of 12:30, 157.71 Down 0.22.

Artificial Intelligence is a Child that needs a Parent to guide it through.

Arthur Mometer
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? For Audiophile On W45D Antenna Atop Ne Tubes

Post by Arthur Mometer » Thu Dec 20, 2018 9:11 am

Audio, does it look like those turnstiles are 1/4 wavelength apart at 44.5 MHz? Not much gain that way. But the wavelength is around 20 feet, and it's on top of that ball of Neon, making it rather inaccessible. I never remember seeing the bare neon tubes. Is there a plastic dome over it now? The newly refurbished HB Weatherball has always had a plastic dome. And for MW, is the old MNB/WZZM-TV WB bare Neon tubes?

Also, look at the turnstile elements. It looks like the elements are tunable by pulling the lower outer diameter telescoping part in and out. Is this an off the shelf model?

CB/FM/HB Weatherball Video. It has always had a dome around the Neon/Gas Discharge tubes. Sounds like somebody from WWCK AM and FM made the video. You can hear the voiceover guy promoting a Whiting Concert on FM, then a little snippet of Rush on the AM. Taylor? I could only think of George Taylor McIntyre, Jim Taylor Hampton, and the former WKMF CE Jim Taylor.

https://www.youtube.com/watch?v=PvIJRa3Z7iQ

MNB/WZZM-TV 13 Weatherball Video. It looks like there is a clear structure supporting the Neon/Gas Discharge tubes, but are they on the outside of the dome?

https://www.youtube.com/watch?v=v8VcnabFL9c


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Deleted User 14803

Re: The Old FM Band 42-50mhz

Post by Deleted User 14803 » Thu Dec 20, 2018 2:40 pm

If FM stations had remained on the 42 MHz band, I bet DX’ing would have been cool. And how long would a telescoping antenna be on a portable radio?



Arthur Mometer
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Re: The Old FM Band 42-50mhz

Post by Arthur Mometer » Thu Dec 20, 2018 3:45 pm

Well, the wavelength is 6-7 meters, so a 1/4 wave is 1.5-1.75 meters, so without some serious loading coils, 5-6 feet. Replacement antennas would be an industry in itself. In a typical 8 foot ceiling room, you'd always be scraping the ceiling. A half wave dipole would be 11 feet long, bigger than many room dimensions. And in the early days, H Polarization only. Tilted and vertical orientation wouldn't be ideal. TV Rabbit Ears with longer elements would be good.

The frequency of Sporadic E openings at 42-50 MHz WOULD have been annoying to the average FM listener, especially as the band matured and had many cochannel assignments.


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Ed Joseph
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Re: The Old FM Band 42-50mhz

Post by Ed Joseph » Mon Jan 07, 2019 5:41 pm

There is still some random stuff in the 49MHz "CB" band. Mostly remotes and monitors, but there are evidently some wireless audio devices that use standard FM-MPX for stereo in this band, which can be decoded easily with an SDR, or even an FM Demod chip. I'm guessing these are simply using a Rohn BA/BH14xx or JRC NM302x modulators just at a lower carrier frequency. I still have a couple old receivers which cover the former FM band, and I'd love to get a nice Yagi up in the air to see what all comes in.


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innate-in-you
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Re: ? For Audiophile On W45D Antenna Atop Ne Tubes

Post by innate-in-you » Fri Jan 11, 2019 10:14 pm

Arthur Mometer wrote:
Thu Dec 20, 2018 9:11 am
Audio, does it look like those turnstiles are 1/4 wavelength apart at 44.5 MHz? Not much gain that way. But the wavelength is around 20 feet, and it's on top of that ball of Neon, making it rather inaccessible. I never remember seeing the bare neon tubes. Is there a plastic dome over it now? The newly refurbished HB Weatherball has always had a plastic dome. And for MW, is the old MNB/WZZM-TV WB bare Neon tubes?
<snip>
That reddish orange ball of neon tubes had been dark for years, but it has been quite recently replaced by a ball that can display a wide variety of color. In recent weeks, I've seen green, magenta, and red hues.
So far, I've only seen the whole ball lit in one color on any given morning. It doesn't spin, blink nor dance, but the color changes from night to night.

I suspect that the technology is similar to the lighting on the face of the Motor City Casino, which, in turn, may possibly be an immense array of small blue, red and green light-emitting diodes (LEDs).



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Ben Zonia
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Re: The Old FM Band 42-50mhz

Post by Ben Zonia » Fri Jan 11, 2019 11:29 pm

Ed Joseph wrote:
Mon Jan 07, 2019 5:41 pm
There is still some random stuff in the 49MHz "CB" band. Mostly remotes and monitors, but there are evidently some wireless audio devices that use standard FM-MPX for stereo in this band, which can be decoded easily with an SDR, or even an FM Demod chip. I'm guessing these are simply using a Rohn BA/BH14xx or JRC NM302x modulators just at a lower carrier frequency. I still have a couple old receivers which cover the former FM band, and I'd love to get a nice Yagi up in the air to see what all comes in.
I used to "DX" that 46/49 MHz duplex band on my scanner. Most of the portable phones have migrated to the GHz range. But you could have a pretty good range with a pair of TV Rabbit Ears with the telescoping whips fully extended. Also the center loaded telescoping scanner antenna from Radio Shack worked much better than the stock telescoping whip on that frequency range. Really good for Private Investigators and Lawyers to collect "evidence". And legal, too. I used it to record my own important phone calls. I asked my Lawyer, and he said it was legal to listen to this (but not cell calls), as long as I didn't reveal to third parties what I heard, and to record as long as I knew I was being recorded, in the State of Michigan. The planned obsolecence of batteries and/or difficulty of buying replacements is the #1 reason people went to the higher and higher frequencies and scrambled scanners. The really old phones used 1610-1720 kHz for the full duplex as I recall, and behaved like carrier current AM stations, except that you needed to use slope detection on the NBFM signal.


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Re: The Old FM Band 42-50mhz

Post by k8jd » Thu Jan 17, 2019 4:09 pm

There was a lot of activity on 30-50 MHz band in my early years of mobile radio repair work.
I could hear sporadic E-layer propagation bringing southern State's Sheriff departmant signals into the Detroit area, strong and clear in the summers. Little by little the users migrated , first to 420-450 MHz and then to 800/900 MHz digital trunked systems.
Recently I scanned 30-50 MHz for days, and only heard one local cement ready-mix truck fleet operating. .
Pretty ripe for a take over.



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Re: The Old FM Band 42-50mhz

Post by WOHO » Fri Mar 29, 2019 12:14 am

innate in you wrote: "...The really old phones used 1610-1720 kHz for the full duplex ..., yes and I had a homebuilt AM Stereo CQuam decoder I built into a tuner, and up at the x-band, I could hear phone conversations from close to a mile a way- no lie, but I had to force the radio into CQaum by rapidly hitting the stereo/mono switch, but it was interesting.
If I'm not mistaken, the bigshots at RCA/NBC and others were intent on killing the FM band, and it did end-up taking the life of one of the pioneers of the original FM band, who took his own life.
The old FM band become the VHF-Low band, and that's why there is no Channel 1 on the ole TV sets as that was in the VHF low band. Eventually, long-range reception was possible with just one single municipal antenna, so highway patrol and state police used VHF-low band for very long range vehicle communication- and should keep as doomsday backup systems. CHiPs, OH, MI, all used the low band for many years, and even tornado sirens used the bank at one time for activation.



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Re: The Old FM Band 42-50mhz

Post by innate-in-you » Fri Mar 29, 2019 1:40 am

I wouldn't say for sure that RCA was trying to kill FM radio. Certainly, there were some broadcasters that wanted it dead since they had things right where they wanted them.

The real fight between RCA and Armstrong was over patent royalties.
Armstrong considered the transmitter and receiver technology to be one in the same. RCA developed the ratio detector to get around Armstrong's patents, shutting him out of royalties he had been expecting to receive, millions upon millions of dollars, since every television set in America would have FM audio for more than half a century.



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Ben Zonia
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Re: The Old FM Band 42-50mhz

Post by Ben Zonia » Fri Mar 29, 2019 5:45 pm

Phone frequencies.

http://www.tech-faq.com/cordless-phone-frequencies.html

As far as I know, all newer cordless phones have scrambling options, if not automatic.

Here's another, more complete list.

http://www.csgnetwork.com/phone1freqtable.html
Last edited by Ben Zonia on Fri Mar 29, 2019 6:10 pm, edited 1 time in total.


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Ben Zonia
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Re: The Old FM Band 42-50mhz

Post by Ben Zonia » Fri Mar 29, 2019 6:09 pm

Phone frequencies.

http://www.tech-faq.com/cordless-phone-frequencies.html

As far as I know, all newer cordless phones have scrambling options, if not automatic.

http://www.csgnetwork.com/phone1freqtable.html


"I had a job for a while as an announcer at WWV but I finally quit, because I couldn't stand the hours."

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