Early Radio Publications

This week I uncovered a treasure trove of early radio magazines in downloadable PDF format. If you love radio history like I do, you will enjoy browsing through these publications. Two magazines are represented.

Radio Broadcast Magazine, available issues from 1922 through 1930, covers in great detail the early years of broadcasting and includes much technical information for the early experimenter. The advertisements from these years alone are worth checking out. Articles in Radio Broadcast run the entire spectrum from MacMillan's expedition to the Arctic in the summer of 1926 to detailed descriptions of current vacuum tube circuit technology, projects for the amateur, to coverage and questions about governmental standards and practices in this early era of radio, to programming content and personalities. What a wealth of interesting information for the historian!

Radio Broadcast Magazine

Also available on this site is Radio Corporation of America's Radio Age  Magazine, available issues from 1942 through 1957. This was a quarterly publication produced by RCA. A lot of interesting World War II coverage can be found during the war years, as well as new technology.

Radio Age Magazine

Be sure to check these out while they are still available.

Internet Radios

I guess I'm too much of an old timer to get into this current Internet "radio" thing. Too many years spent toying with tuned circuits and antennas, too many years a radio DXer, radio listener, even a radio "Ham" - some 47 years - though I really haven't done the Ham thing for some time. WE7W lives on though, and I still keep my license current.

For better or for worse, sometimes words or things in life "evolve" over time to mean different things. I'm thinking radio is becoming one of them. Radio at one time meant "wireless" transmission of electromagnetic waves through the air, from starting point to finishing point. It was picked up magically with a wire or a coiled loop, fed to a tuned circuit which selected one signal out of many, detected and converted to audio which was then amplified so you could hear it. Internet "radio" is no such thing. No aerial, no tuned circuits, no detection. A friend of mine says real radio has to pass through your body (meaning: the waves) - that's the definition of real radio. I say that too, plus a tuned circuit must surely be involved, and almost certainly a detector. Internet "radio" has none of the above. What would Marconi think?

Internet radio probably is radio only in the sense that for a small segment of its "transmission" to you, millions of digital bits are perhaps beamed up to a satellite and back down. Maybe. The rest of its journey, both before and after, it is transmitted through wire or fiber optic cable, passed from one computer device to another to another, arriving in numerical perfection just as it was sent, down to the last, solitary, Boolean bit.

Merriam-Webster says about the noun RADIO:

a: the wireless transmission and reception of electric impulses or signals by means of electromagnetic wave.

b: the use of these waves for the wireless transmission of electric impulses into which sound is converted.

As I was saying: "waves", like the kind that pass through your body.

There was even a time when I used to subscribe to various radio magazines, until the articles became more computer articles than radio articles, each filled mostly with links to web sites. Recent shortwave magazine articles I've seen basically contain narrative on how to navigate a radio station's web site to get its streamed Internet content. Radio magazines have evolved to something different than they once were, too.

I just don't get it. There is no magic for me in Internet radio. See accompanying photo of toaster, er, I mean Internet radio. How about you?

Maybe it's the semantics of the whole thing that bothers me more than anything else. The new "radio" is not the old radio, and never will be. It is something wholly different.

Okay, a reality check. Yes, I do listen to a podcast now and then (now there's a new word unleashed on modern society for you: podcast), or streamed audio via my desktop or laptop. I've even been known to listen to a streamed radio station on occasion (try streamed KTNN-660 sometime, The Navajo Nation, 50KW out of Window Rock, AZ for an interesting experience). But the listening is done for "content", without the accompanied magic of original radio. There is no "feel" to it. I attempted to capture this feel in another post in this blog. I was talking about mediumwave towers:

...."A tower is a thing of beauty to the radio aficionado....Ah, the mediumwave broadcast tower! Think of it! Stately, striped sentinels with strobe lights flashing, they number thousands and thousands across the country, each emitting invisible waves of electrons through the late night air, spanning that mysterious thing called "the ether" to deliver communication to unknown distant masses. It conjures up thoughts of far-away points on the landscape, souls crouched in cramped corners with headsets fixed in the dark of night, straining to make sense of distant babble through static crashes and heterodynes. That would be me. The whistle of a far off freight train gives the same feeling of wonder."

Internet radio does not. Do you like your toast light or dark?

Mediumwave Oddities - Towers

Today, we move on to tower oddities in the mediumwave broadcast band. Broadcast towers have always been an interesting subject to me. Did you see the news earlier this month on the WWVA-1170 towers collapse, due to severe storms in the Wheeling, WV area? The photo at left shows how they looked in the 1940s. WWVA-1170 started broadcasting in 1926.

Like last time, we will use data from current FCC records dated August 7, 2010. There are 4784 licensed stations in this survey. Previous posts in this series were Mediumwave Oddities - Transmitter Power and Mediumwave Oddities - Geography. Information has been gathered using the Radio Data MW program.

Again, daytime and nighttime data will differ. I will be explicit on which is which when the statistics are presented.

THE DAYTIME

Many mediumwave broadcast stations use multiple tower arrays to direct their signals towards intended markets, or away from other stations which they may cause inteference to. There are thousands of towers out there.

If we total all the towers of all the mediumwave stations transmitting in the daytime, how many would there be?

Answer: 7164. That's a lot of metal in the air.

Out of the 4784 licensed stations, how many stations have only one broadcast tower?

3569 stations have only one broadcast tower, which is 75% of all broadcast facilities. Surprisingly, the remaining 25% actually have more towers total than the single-towered 75%. Multi-towered stations average 2.95 towers per facility.

Essentially, a station with one broadcast tower has an omni-directional signal pattern, in other words, the station broadcasts with equal signal strength in all compass directions. Multiple tower arrays use phasing techniques to form skewed patterns of radiation, often in figure-eight or cardioid shapes. The lobes, or strong points of the pattern are directed towards market areas of interest. The nulls, or weak points of the pattern, are positioned toward areas to lessen interference with other stations or unwanted markets.

Back to tower counts, how many stations have two broadcast towers?

515, or 10.7 percent of the total have two towers.

How about three towers?

384, or 8 percent of the whole. The percentage drops dramatically off from there of course.

Which station has the most broadcast towers in use during daytime hours?

That would be KNTH-1070, Houston, Texas, with 11 towers. They are arranged in an odd grouping of three parallel rows of 3 each, with towers #10 and #11 jammed between the two rows. The rows head generally in a south to north direction. KNTH-1070 uses two less towers (9) during nighttime hours.

Are there more towers in daytime use east of St. Louis, Missouri, or west of St. Louis?

East of St. Louis, there are 4240 towers in use during daytime hours. 2924 towers are used west of St. Louis.

Radio station signal patterns are sometimes further modified at the tower site by what are called "augmentations". Augmentations are modifications to the standard broadcast signal pattern, usually to further null the signal strength in a certain direction to bring it into FCC "signal contour" compliance. An interesting discussion can be found on augmentation over at The Virtual Engineer AM forum.

Stations can have up to 28 augmentations to their signal pattern. This must be a technical nightmare for the broadcast engineer.

Which station has the most augmentations?

Four stations have 28 augmentations in use during daytime hours.

THE NIGHTTIME

Again, like we saw in Mediumwave Oddities - Transmitter Power, nighttime seems to be the more interesting as it has more odd variety.

How many total towers are used for broadcasting during nighttime hours?

Answer: 7877 towers. 713 more towers are used at night than during the day.

Being a mediumwave DXer, you know that signals travel much farther at night than during the day, commonly upwards of 1,000 miles and more. Stations often must follow different signal pattern guidelines at night to prevent interference to distant stations. This generally requires use of either a different tower arrangement or different number of towers, or both. Stations also may operate at reduced power at night.

Which station has the most broadcast towers in use during nighttime hours?

That would be KFXR-1190, Dallas, Texas, with 12 towers. They are arranged in two parallel rows of 6 each, heading from southeast to northwest. KFXR uses only 4 towers during daytime hours. Texas holds the record for stations with the most broadcast towers for both nighttime and daytime hours. They always do things in a big way in Texas.

Are there more towers in nighttime use east of St. Louis, Missouri, or west of St. Louis?

East of St. Louis, there are 4427 towers in use during nighttime hours. 3450 towers are used west of St. Louis.

Which station has the most augmentations?

Nine stations have 28 augmentations. Among them again is KFXR-1190, Dallas, Texas. I think KFXR-1190 should be considered for the record here. It is the station with the most towers (12) and tied with 8 others with the most augmentations.

I was thinking about ground radials this morning, which are the (generally) buried wires that are placed under broadcast towers to create the artificial ground that they operate over. Usually broadcast towers must have at least 90 quarter-wave length wires, and as many as 120 or more. Seeing as how we know the number of broadcast towers used in nighttime operation, the following question occurred to me:

If we assume 120 radials under each tower, how many total ground radials are in use?

Answer: 945,240. Almost a million radials.

Using an average length of 245 feet for each radial (a quarter wave length at 1000 KHz), how may feet of radials lie under mediumwave broadcast towers in the US?

231,583,800 feet. That is 43,860 miles of wire, enough to encircle the world almost two times. Time to buy stock in copper.

Hope you have enjoyed this series. For more mediumwave oddities on RADIO-TIMETRAVELLER, see the Tower Talk article.

The WWVA-1170 towers after the August 4th, 2010 storm.

Australian Mediumwave Database

I came upon an official Australian government link (ACMA - The Australian Communications and Media Authority ) the other day which documents licensed mediumwave stations for Australia in PDF format. Digging deeper, I found an official government database, published in XCEL (.XLS) format. This file has the basic information, such as call sign, frequency, latitude, longitude, power, and service. No tower information is available, and only a crude maximum signal strength of the antenna pattern's maximum lobe is given. It is also a comprehensive file of all Australian transmitter data: MW, FM, and TV. None the less, it will be useful.

Using an XCEL viewer, the mediumwave information can be copied in its entirety and saved as a text file. Further "massaging" can put it into a proper format. Then the information can be incorporated into a database of Australian mediumwave stations. The file is updated once per month.

List of licensed broadcasting transmitters (main page)

Broadcast transmitter data (EXCEL format)

Mediumwave stations, by call sign order (PDF)
Mediumwave stations, by frequency order (PDF)
Mediumwave stations, by area served (PDF)