General – Page 19 – Engineering Radio

The efficacy of the computer generated voice

I was just listening to the latest broadcast of severe thunderstorm and tornado warnings rolling in across WXL-37 for upstate NY:

It looks a little bit hairy to the north. There is a lot of rumbling around to the west of us and we are prepared to head for the basement in event of a tornado in this area.

At some point in time, somebody decided that computer-generated voices were exactly right for emergency communications. Never mind some of the quirks that can be encountered. These are mostly pronunciation errors for places like Saugerties, normally spoken as Saw-ger-tees but the NOAA computer voice says S-ouw-jer-tees. That is understood well enough, but frankly, there are other place names that go by so fast that I cannot make sense of what the computer is saying.

Another good example of this is the Coast Guard’s computer voice confusion around the word “November.” In the military (NATO) phonetic alphabet, November is the word used to express the letter N. For some reason, the word itself seems to be a bit of a mystery to the computer, which sometimes renders the word November as “NOVEMBER OSCAR VICTOR ECHO MIKE BRAVO ECHO ROMEO.” For those of us who have been in the military, this makes perfect sense. Why just say “November” when you can say much more, waste time, and confuse the un-aware? This particular computer voice is nick-named “Iron Mike.”

Computer-generated voices can be hit or miss.

Then there is the computer voice from Shannon VOLMET:

Even on HF Single Side Band, that voice is clearly more understandable than the NOAA voices in use today. The issue is, many broadcast stations now use the NOAA computer voice to broadcast weather alerts to their listeners. If I were driving in my car with lots of background noise, I likely would not get most of the information being relayed by the broadcast station via EAS. I suppose gone are the days of a professional broadcaster’s voice clearly imparting information and comforting the listeners during times of calamity. Sigh.

WEBE pictures

WEBE is fairly unique in that its antenna is mounted on the side of a 500-foot smoke stack. I took a few pictures last winter:

This is a close-up of the Antenna:

WEBE main antenna, Shively 6 bay half wave spaced, ERP 50 KW

Here is an even closer view from a different angle:

From this angle, one can see the mounting brackets and the wire mesh reflector installed on the smoke stack. From the first picture, one can see that the 400 MW PSEG coal fired power plant puts out a lot of combustion products when on line. Combustion is an exothermic chemical reaction that looks like this:

Hydrocarbon Fuel + Oxidizer + Nitrogen → Heat + CO₂ + H₂O + NO_x

Included in this are any trace elements that are found naturally in the coal that is being burned. These include things like Mercury, Nickel, Uranium, et cetera. These trace elements can concentrate around the smoke stack because they fall out of the particulate quickly and these plants burn a lot of coal. The above picture was taken on a very cold day, most of what is coming out of the smoke stack is steam.

The issue for the radio station is when the particulate matter accumulates on the antenna, effectively shorting it out. The solution was to place the RADOMES around the elements and then constantly purge the RADOMES with nitrogen. Thus, this liquid N2 tank is vital for the operation of the radio station:

Each element of the antenna has a small hole in the feed line. N2 is fed continuously into the transmission line at a pressure of about 1.5 inches water column which then purges the RADOMES keeping any combustion products out of the RADOMES. The N2 tank needs to be changed out every 18-21 days and weights over 650 pounds when full.

A brief Pictorial History of early micro-computers

I enjoy history, perhaps more so than others. My first computer was an Apple IIC, purchased in 1985. It had a single 5 1/2 inch floppy drive, no hard drive, and a wee little monochrome monitor. Basically, it was a glorified word processor until I figured out how to connect it to my Amateur Radio transceiver. Here is a picture of my radio room, circa 1988 on Guam:

Finding more things to do with it became a hobby of sorts. After a while, I realized that what I wanted was what we termed an “IBM clone,” what is known as a PC today.

When I came across this blog post; History of Computers, I found it interesting and thought I’d share.

Enjoy!

Those Shortwave Sites

It is a joke circulating in Russia at the moment. Kind of funny when you think about it.

In light of the developing situation in Eastern Europe, it may be wise to retain some of those HF broadcasting (AKA Shortwave) sites. It may be too late for Canada, however, the US government still has a few high-powered HF sites that they may want to hold onto for a while. There are several ways that shortwave broadcasting can be beneficial.

Like all radio broadcasting, quality content is needed to attract listeners. Most of what is available on shortwave are religious or transparent government propaganda. There are exceptions to this, but they are rare. Introduce quality programming, and shortwave listenership will increase.
DRM 30 (Digital Radio Mondial) is still in its experimental phase. It has been demonstrated to work reasonably well on HF. Several digital data formats are successfully being used on HF; HFDL, ALE, STANAG 5066, PACTOR and others. DRM 30 has the advantage that H.264 video can also be transmitted.
The VOA has been experimenting with images transmitted via MFSK, AKA the “VOA Radiogram.”
HF is always susceptible to changing propagation. However, it can be reliable enough, especially when frequency diversity is employed, to overcome these issues when no other method of communication is available.
DRM and MFSK can be decoded using a simple shortwave radio and a computer sound card. A DRM CODEC is required, but those are readily available for download.
Analog shortwave broadcasting using AM is still viable. AM has the advantage of being extremely simple to receive and demodulate. Simple receiver kits can be built and run on 9 volt a battery.
While the Soviet Union had an extensive jamming network, those sites have long since been non-functional. Most countries have discontinued the practice of jamming with the exception of China, North Korea, Cuba, and perhaps some countries in the middle east (the usual suspects).

Sample of DRM reception via shortwave:

If the internet is censored or somehow becomes unavailable in that part of the world, shortwave may be the only method to convey an alternate point of view.

Hopefully, things will settle down and return to at least a civil discourse. However, it never hurts to have a plan.