This is a trip down memory lane. Someone has taken the time to preserve and document Radio Shack, its founding, history, and all of the catalogs printed from 1939 to 2005. The website archive is Radio Shack Catalogs.
I remember reading these very catalogs cover to cover when they came out in the mid-1970s. At that time, this stuff looked expensive, and in relative dollar terms compared to today, it was. We had one of these computers in our “Math Lab” in 9th grade:
Radio Shack catalog, TRS-80
In fact, when I found one of these computers stashed away in the corner of a transmitter site, I had a flashback of Mr. B scowling as yet another student made a mistake plotting x/y coordinates on the backboard.
Historic VLF (Very Low Frequency) station SAQ Grimeton will be on the air to celebrate United Nations Day on October 24th at 10:30 UTC (6:30 am EST) on 17.2 KHz CW. This station was established in 1922 and is the last radio station in the world employing an Alexandersontransmitter. More information at their website.
This is a great 2011 video of a tour of the station, including transmitter start-up:
It is great to see that old gear come to life and transmit a message. The electric motor/generator sounds like a jet engine spooling up.
Before solid-state or even hollow-state rectifiers, motor generators were used to create the DC voltages needed to transmit high-power radio signals. This method was used by high-powered Naval shore stations through WWII and beyond.
By way of comparison, an average CW operator can send and receive Morse code at about 20-25 words per minute. A good CW operator, about 30 words per minute and a Russian CW operator, somewhere near 50 words per minute. This was the main wireless data transmission method until Radio Teletype came into widespread use in the 1950s. Here is a comparison of data speeds through the years:
Method
Speed
Bits/S
CW
20 WPM
8.3
CW
35 WPM
14.58
Radio Teletype*
75 Baud/100 WPM
41.6
Radio Teletype*
100 Baud/133 WPM
55.41
Async data
300 Baud
300
Async data
1200 Baud
1200
Async data
9600 Baud
9600
Switched 56 (Switchway)
56KB
56,000
DS0 (POTS)
64KB
64,000
ISDN
64KB X2
128,000
DS1 (T-1)
1.54 MB
1,540,000
DS3 (T-3)
45 MB
45,000,000
Ethernet
10BaseT
10,000,000
Ethernet
100BaseT
100,000,000
Ethernet
Gigabit
1,000,000,000
The Morse Code (CW) and Radio Teletype data rates are not a direct comparison, as most radio teletype systems use 5-bit Baudot code instead of 8-bit ASCII. Morse code varied in length from one to five bits, if one thinks of each dot or dash as a data bit. Back in the day, before the “Netcentric” mindset, we used mainly radio teletype to communicate from ship to shore. A premium was placed on brief, concise, operational communications. Everything else was sent via the mail.
It is quite amazing to see the increase in data speed, which directly correlates to information exchanged (or the ability to exchange information) in the last 90 years.
To receive SAQ Grimeton, one needs a VLF receiver or converter capable of receiving 17.2 KHz and a very quiet receiver location. There are many VLF hobbyists that will be tuning in.
I have covered numbers stations before. This is a radio program from BBC Radio 4 first broadcast in 2005. It is an interesting look what is known and not known about various numbers stations around the world.
Somebody working to preserve a record of past work:
Some of these have familiar looking cabinets and tube arrangements. They all look like classics to me and it is good that they are being saved. I noticed at the end of the video there is a Harris MW10A. As for the RCA Ampliphase transmitters; I maintained a BTA5J in Harrisburg PA on 580 KHz. It was reliable enough, but I could never keep it sounding good for more than a couple of days.
In any case, a worthwhile effort. More information at: AWA Transmitters.
