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.
In my never-ending fascination with broadcast transmitters, I bring you the Harris/Gates BC1H. This is an updated model of the BC1G, the main difference being the solid-state audio and oscillator sections in the later H model. This design uses the simple 833 parallel final and 833 push-pull modulator
Sales brochure, click to download the four-page .pdf
Harris/Gates BC1H Transmitter running at 1,000 watts into the antenna. Like many old tube transmitters, this sounds great on the air. The transmitter was made in 1975 and is in backup service. For a 37 year old transmitter, it runs like a champ and comes on consistently. Like the preceding Gates BC-1 models, this transmitter is rugged and reliable. My only comment is the transistors in the solid-state driver section are no longer available. If that were to become an issue, one can always look up the tube audio driver from previous versions (T and H models). It would be a shame to throw away a good transmitter for lack of a couple of transistors, but I know some who have done just that.
This is one of the possibilities that has been bantered about as a solution for the “AM problem.” The theory goes as such; former TV channels 5 and 6 (76 – 88 MHz), which are not suitable for DTV would be an ideal place for the existing AM stations to move. That represents a 12 MHz chunk of spectrum, which is much more than the current 1.16 MHz spectrum the current AM broadcasting service takes up (.54 to 1.7 Mhz). An added benefit is that the VHF spectrum does not have the skywave “problem” that the MF spectrum does, thus many more stations could be licensed to the service. Everyone would benefit, and AM stations would get a new lease on life in the FM band. The number of stations would increase by several fold, including LPFM, non-commercial, and translators. AM stations would no longer be burdened with expensive directional arrays or substandard audio quality.
It seems almost too good to be true…
The FCC reportedly promised “take a hard look” at this idea back in 2008. Four years later, one wonders what has become of it.
A quick search of the existing TV stations licensed to channels 5 and 6 reveals the flaw in this theory. The FCC has re-licensed many full powered and Low Powered DTV stations to channels 5 and 6 since 2008.
List of full power channel 5 stations:
Call Sign
Service
Status
City
State
Fac ID
ERP (kw)
HAAT (m)
Licensee
WOI-DT
DT
LIC
AMES
IA
8661
13.9
566
CAPITAL COMMUNICATIONS COMPANY, INC.
WGVK
DT
LIC
KALAMAZOO
MI
24783
10
169
GRAND VALLEY STATE UNIVERSITY
WBKP
DT
LIC
CALUMET
MI
76001
6.4
301
LAKE SUPERIOR COMMUNITY BROADCASTING CORPORATION
KXLF-TV
DT
LIC
BUTTE
MT
35959
10
588
KXLF COMMUNICATIONS, INC.
KXGN-TV
DT
LIC
GLENDIVE
MT
24287
1
152.4
GLENDIVE BROADCASTING CORP.
KHAS-TV
DT
LIC
HASTINGS
NE
48003
45
217
HOAK MEDIA OF NEBRASKA LICENSE, LLC
WLMB
DT
LIC
TOLEDO
OH
17076
10
155
DOMINION BROADCASTING, INC.
KOBI
DT
LIC
MEDFORD
OR
8260
6.35
823
CALIFORNIA OREGON BROADCASTING, INC.
KIVV-TV
DT
LIC
LEAD
SD
34348
9.2
561
KEVN, INC.
WTVF
DT
LIC
NASHVILLE
TN
36504
22
425
NEWSCHANNEL 5 NETWORK, LLC
WMC-TV
DT
LIC
MEMPHIS
TN
19184
34.5
308
WMC LICENSE SUBSIDIARY, LLC
KCWX
DT
LIC
FREDERICKSBURG
TX
24316
23.7
412
CORRIDOR TELEVISION, L.L.P.
WCYB-TV
DT
LIC
BRISTOL
VA
2455
29.9
743
BLUESTONE LICENSE HOLDINGS INC.
WDTV
DT
LIC
WESTON
WV
70592
10
240
WITHERS BROADCASTING COMPANY OF WEST VIRGINIA
WIWN
DT
LIC
FOND DU LAC
WI
60571
9
338
WWAZ LICENSE, LLC
List of Low Power Channel 5 stations (analog):
Call Sign
Service
Status
City
State
Fac ID
ERP (kw)
HAAT (m)
Licensee
KSCT-LP
TX
LIC
SITKA
AK
15348
0.049
0
DAN ETULAIN
K05KF
TX
LIC
DILLINGHAM
AK
792
0.16
0
ALASKA CORP OF SEVENTH DAY ADVENTIST
KRDN-LP
TX
LIC
REDDING
CA
127179
0.6
0
KM COMMUNICATIONS, INC.
W05CO
TX
LIC
SARASOTA
FL
66995
3
0
THREE ANGELS BROADCASTING NETWORK, INC.
W05CJ
TX
LIC
KEY WEST
FL
125642
0.59
0
JAMES J. CHLADEK
DKHHB-LP
TX
LIC
HILO
HI
126233
3
0
KHHB, LLC
WIKY-LP
TX
LIC
EVANSVILLE, ETC.
IN
61036
0.14
0
ROBERTS BROADCASTING COMPANY OF EVANSVILLE, IN, LLC
Looking through this data, particularly the digital licenses which were granted since 2009, one an only assume that the FCC has, by de facto, nixed this idea if it ever considered it at all.
