The Centennial Begins!

[Kent King]

100 years ago today (Dec 27, 1924), E. H. Scott used his World's Record Super in Tasman New Zealand and heard station WOC, Davenport, Iowa, a distance of almost 8000 miles. For the next 3 months, Scott would log dozens of US stations while in vacation in New Zealand. This accomplishment started him on a 20-year radio business resulting in the sets we collect today. I will be highlighting various centennial dates here in the future!

[David C. Poland]

According to the Fall 1924 issue of Citizens Radio Callbook, broadcast power of these 3 stations was:

WOC Iowa.             500 watts.      620 KC.  Palmer School of Chiropractor

KHJ  Los Angeles.  500 watts.      760 KC.  Times- Mirror Co (newspaper?)

KGO  San Fran.     1,000 watts.    960 KC.  General Electric Co

About 500 US radio stations are listed in this issue. Consider how new this industry was given that Westinghouse' s KDKA in Pittsburg is considered the first US commercial radio station going on the air November 1920. (KDKA was listed at 1000 watts Fall 1924).

In this Fall 1924 issue, many station's power was as low as 5 or 10 watts. many at 50 or 100 watts. A few at 500 watts. Even fewer at 1000 watts, like maybe 2 or 3 per  100 stations. Saw none over 1000 watts. Some stations list being on the air for only portions of the day.

Today, 250 watts is a small station. Many at 5000 watts. Clear channel stations at 50,000 watts. In the later 1930's, WLW had a 500,000 watt transmitter allowed to broadcast at that power at times , which transmitter became part of Voice of America during WW2. I recall a 250,000 watt station in Mexico across the border from TX.

[Y2K Bruce]

I have WOC radio on now listening on my circa 1940 Phantom AM/FM 28 tube Scott. I live about 10 miles from their tower though.

[Scott Seickel]

Must have had some great ionospheric conditions. 

[Thomas Day]

Several years ago, after I got my Allwave 23 working, I found and was able listen to Radio New Zeland for a few minutes. 

Thom. 

[Thomas Day]

Thomas Day said:

Several years ago, after I got my Allwave 23 working, I found and was able listen to Radio New Zeland for a few minutes. 

Thom. 

[Alex R. Whitaker]

When I think about the noise floor, today, I think that Scott's reception feat from 100 years ago would not be able to be duplicated.  Add in the fact that almost all those stations, like Dave P. said, are considered low power today, makes it even more non-repeatable. 

[Norman S Braithwaite]

The noise floor was very high in the early days of broadcasting due to lack of noise suppression on all kinds of machinery including automobiles.  The feat would be difficult to reproduce today due to crowded bands.

Norman

[Alex R. Whitaker]

However, there were a  lot less machines around that generated electrical noise then than the millions of noise makers that are around today.  I don't know.....if there had been equipment around back then to measure the noise floor, we could compare.  But, all we can do is speculate.  I do know this:  I worked for the Indiana State Police Radio Communications Division from 1995-2009.  During that time, we phased out the low band VHF system, which had been in place since 1947 (ISP had used low band as a mobile TX since around 1942).  Part of the reason the system had to be replaced was that the noise floor had come up so much that both base and mobile transmitters were not getting the distance they previously did.  One fellow employee, who had lived in central Indiana all his life, said that he used to be able to monitor ISP all over the state on 42.42 MHz (base TX) at his home, about 35 miles west of Indianapolis.  Before the system was replaced, he said he could only hear a fraction of what he used to be able to.  Of course, sunspot cycles and ducting, etc. have to be considered, but they don't make the difference that he and the employees involved with communications all saw.  

Norman S Braithwaite said:

The noise floor was very high in the early days of broadcasting due to lack of noise suppression on all kinds of machinery including automobiles.  The feat would be difficult to reproduce today due to crowded bands.

Norman

[Norman S Braithwaite]

Interesting.  I thought civil service radio communications in the 42-mhz band were FM.  There was no shortage of noise sources in the early days of radio broadcasting and the noise sources were robust and widespread.  Aside from industrial sources like large motors and welding, there were home medical devices including electrotherapy and violet ray, battery chargers, and one lung engines on small farms.  Arc lighting was still being used on streets and in theaters.  Medical offices had all kinds of equipment producing RF noise.  None of these noise sources were suppressed until several years after radio became a popular medium and even then it was a gradual transition.

Norman

[Alex R. Whitaker]

42 MHz was FM.  But, the noise floor is there, nevertheless.....causing receiver desense.   That was the reason that our radios all had noise blankers....not just for noise inside the vehicle, but from outside as well.  I do see your point about arc lighting, unsupressed electric motors, vehicle ignition, etc.  The broadband noise would be carried by the ionosphere, just like radio signals,  on similar frequencies, bringing up the noise floor in all sorts of places.  It would be interesting to see if Scott's feat could be duplicated today.  

[Norman S Braithwaite]

Thanks for the explanation.  I had not thought about how the noise floor would desensitize FM reception.

Norman