The 73 kHz, 136 kHz and 160-190 kHz Amateur VLF Bands

The 73 kHz, 136 kHz and 160-190 kHz Bands

SAQ Grimeton 17 kHz Transmissions News

Oklahoma Beacon Updates - 2004

With no Amateur Radio low-frequency allocation in North America, stations operating under FCC Part 5 Experimental licenses
in the US or under special experimental authorizations in Canada nonetheless continue to
research the nether regions of the radio spectrum. By and large, LF experimentation is occurring in the vicinity of 136 kHz--typically 135.7
to 137.8 kHz--where amateur allocations already exist elsewhere in the world. The FCC rejected the ARRL's 1998 petition for LF allocations at
135.7 to 137.8 kHz and 160 to 190 kHz, however, after electric utilities objected that ham radio transmissions might interfere with power line
carrier (PLC) signals used to control the power grid.

"Most of the new LF activity of Part 5 licensees has been in the shared 137 kHz amateur allocation available in some parts of the world," says
low-frequency experimenter Laurence Howell, KL1X/5. "Although not in the Amateur Radio Service, these Part 5 experimental stations continue to
add to our knowledge on propagation and engineering."

The holder of Part 5 Experimental license WD2XDW, Howell who's also GM4DMA, previously operated LF from Alaska. He's since relocated to
Oklahoma, and has now resumed his LF work on 137.7752 and 137.7756 kHz. Already he's reporting some spectacular success, despite antenna
limitations. On October 28, New Zealand LFer Mike McAlevey, ZL4OL, copied WD2XDW's 137 kHz carrier "bursts" over a path of more than 13,000 km (8000 miles).

Howell believes the reception probably marked the first transpacific reception of a US-generated signal. "The land mass between Oklahoma and
the ocean was considered to be a large obstacle to long-range communications," Howell remarked, "but obviously not."

The next day, Jim Moritz, M0BMU, copied the LF signals of three North American in the vicinity of 137 kHz (137.777 kHz)--including Howell's
WD2XDW and WD2XES, operated by John Andrews, W1TAG, in Massachusetts--using Argo software, which can detect signals not
otherwise readable. The third station, Joe Craig, VO1NA, in Newfoundland, has been operating a beacon on 137 kHz. Howell says, VO1NA's signals serve as a
bellwether of LF transatlantic propagation. LF signals of European amateurs likewise are heard in North America.

On November 12, Andrews and another LF experimenter in Massachusetts completed the first two-way data exchange between Part 5 Experimental
license stations on 137 kHz. Andrews worked Warren Ziegler, K2ORS, operating as WD2XGJ in Wayland, using conventional CW. The stations are
about 25 miles apart, and both used loop antennas for transmitting. Jay Rusgrove, W1VD, some 100 miles to the south in Connecticut, monitored
and recorded the QSO.

In British Columbia, Lorne Tilley, VE7TIL, and Steve McDonald, VE7SL, have been heard throughout North America on LF. Howell says both are starting
a formal study of variances in groundwave propagation.

Howell says the disturbed solar conditions earlier this month wiped out long-haul paths through or close to the auroral oval during nighttime
hours--especially at higher latitudes. He notes, however, that daytime signals over paths of between 1000 and 1500 km (620 and 930 miles)
showed increased signal strengths during the disturbances. Howell has more LF information on his Web site .


From Newsline, APRIL 20, 1999

The FCC has granted a one year experimental license to the Amateur Radio Research and Development Corporation which is better known as AMRAD. AMRAD plans to use it to conduct ultra low frequency tests on 136.75 kHz.

The purpose of the experiments is to gain low frequency experience in anticipation that the FCC may allocate Amateur spectrum at 136 kHz. The transmissions will be carried out from twelve sites in Northern Virginia. The callsign used will be WA2XTF.


Date: Wed, 31 Mar 1999
From: "ARRL Members Only Web site"

ARLB022: ARRL rebuts late-filed power industry arguments in LF

QST de W1AW  
ARRL Bulletin 22  ARLB022
From ARRL Headquarters  
Newington CT  March 31, 1999
To all radio amateurs 

The ARRL has rebutted assertions that amateur LF allocations at 136
and 160 kHz could lead to interference with utility-operated power
line carrier (PLC) systems.  The unallocated and unlicensed Part 15
PLC systems are used by electric utilities to send control signals,
data and voice.  At the same time, the League urged the FCC to issue
a Notice of Proposed Rulemaking to open the LF bands up to amateurs.

Last October, the League petitioned the FCC to create low-frequency
Amateur Radio allocations at 135.7 to 137.8 kHz and 160 to 190 kHz.
The ARRL proposed permitting CW, SSB, RTTY/data, and image emissions
at a maximum power level of 2 W effective isotropic radiated power.
The utilities' PLCs operate between 10 and 490 kHz.

The comments in question--from four parties including Commonwealth
Edison and Mark Simon--arrived at the FCC well beyond the December
23, 1998, comment and the January 7, 1999 reply comment deadlines.
They also appear to be the only comments filed on behalf of the
power industry.

The League has requested that the FCC strike the late comments from
the record, but it also rebutted their substance in case the FCC
decides to accept them anyway.

The League debunked Simon's suggestion that ham interference could
lead to dire consequences to unlicensed PLC systems.  The League
said Simon fails to explain why a marginal-level amateur signal
would cause problems ''where loud static crashes in the same bands do

The League said PLC systems already have been shown to operate
effectively ''in an environment of extremely high power government
stations using thousands of watts of EIRP.''

The League also took ComEd to task for suggesting that hams be
obliged to protect PLC systems against interference.  The ARRL
pointed out that PLCs have ''no incumbent allocation status'' and are
not entitled to protection from licensed systems.  The ARRL
acknowledged existence of the PLC systems in its October petition
and provided a technical analysis indicating that amateur
interference to PLCs was unlikely.

The League suggested that the utilities make available an industry
database of PLC operating parameters that hams could consult as a
guide to avoid interference.  It concluded that the FCC should not
make allocations decisions ''based in whole or in part on the
presence or absence of Part 15 devices in a particular band segment''
since the devices have no inherent allocation status.

The League said it remains willing to address any interference cases
that might arise and urged the FCC to issue a Notice of Proposed
Rulemaking on the ARRL's request ''without further delay.''


A serious effort by several Dutch radio amateurs to work as many other ultra Low Frequency stations as possible has resulted in QSO's between PA2NJN and several stations in the United Kingdom and Europe. This, on a frequency of 136 kHz using a kite antenna.

The original test was scheduled for November 14th. Plans called for using a kite borne 900 foot long wire antenna, but that day produced no wind. However, the following Saturday, November 21st, provided enough wind to loft the wire to about 80 degrees, nearly vertical.

The group used a loop antenna and an "active antenna" for receiving, but Nico Nienhuis, PA2NJN, reports that once the transmitting antenna was in the air, they were unable to receive. The transmitter output power was 150 watts. Stations worked included G3KEV, G3YXM, G4GVC, ON6ND and ON6UX. PA2NJN also got reception reports from several European listeners, including France, Germany, Sweden, Scotland, and Italy. The best DX was a listener report from IK5ZPV in Italy, a distance of 1095 km away.

The VK LF Band

Meanwhile, Australia's radio regulatory agency says that it is more receptive to a request from the Wireless Institute of Australia that a low frequency band be allocated to radio amateurs. Up until now, radio amateurs wanting to experiment on that part of the spectrum needed to take out a Scientific License. The agency says that it is aware of that Low Frequency allocations are being made overseas, and it will be looking at the CEPT European allocation of 135.7 to 137.8 kHz. The FCC is also considering Low Frequency access by hams here in the USA.

IN older news:

FCC assigns RM number to ARRL petition: The FCC has assigned a rulemaking petition ("RM") number to the League's petition for low-frequency allocations at 136 kHz and 160-190 kHz. The number is RM-9404.

Those commenting on the petition should refer to this number when filing comments with the FCC. Among those commenting to date is Texas Instruments, which markets RF identification products such as the Mobil SpeedPass that operate in the 121-134.2 kHz range.

ARRL Proposes new VLF Privileges...

The ARRL Letter, Vol 17, No 44 (NOVEMBER 1998)


The ARRL has petitioned the FCC to create two low-frequency Amateur Radio allocations at 136 kHz and at 160 kHz. "These allocations will permit experimentation with equipment, antennas, and propagation phenomena in a small segment of the radio spectrum that has not been available to the Amateur Service for many years," the League's petition declared. The petition was filed with the FCC October 22.

Specifically, the League has proposed permitting CW, SSB, RTTY/data, and image emissions for amateurs in a 2.1-kHz "sliver band" from 135.7 to 137.8 kHz and in a 30-kHz segment from 160 to 190 kHz. The 135.7 to 137.8 kHz band adheres to the European Conference of Postal and Telecommunications Administrations (CEPT) band plan.

The ARRL has proposed allowing a transmitter output in both LF segments of 200 W PEP, but in no case greater than 2 W EIRP (effective isotropic radiated power). The League's petition points out that poor antenna efficiencies and ground-loss characteristics likely would keep EIRPs at less than 1 W. The two bands would be available to General and higher licensees.

Unlicensed experimenters--some of them hams--currently operate on LF in the US under the FCC's Part 15 rules. These limit transmitter input power to 1 W and impose substantial restrictions on the size of the antenna. The proposed allocations "will provide the only low-frequency allocation for amateur use and will accommodate more flexible experimentation than is permitted under current Part 15 regulations," the League's filing said.

Hams would be secondary to the Fixed and Maritime Mobile services in the 136-kHz allocation, and secondary to the Fixed Service in the 160-190 kHz band. The League said its engineering surveys suggest that hams could operate in the two segments without causing problems to power line carrier (PLC) systems already active in that vicinity or to government assignments. Unallocated, Part 15 PLC systems are used by electric utilities to send control signals, data and voice.

Calculations included with the League's filing demonstrate how inefficient even relatively large radiators can be on LF (136 kHz is approximately 2205 meters). For example, at 200 W TPO (transmitter power output) and a 200 foot vertical radiator, efficiency is only in the range of 1%, yielding up to 2 W EIRP. A more practical setup--200 W TPO into a 100-foot vertical radiator (efficiency of 0.2%) would yield an EIRP of between 100 and 400 mW.

Several countries throughout the world already enjoy LF allocations. These include New Zealand, Great Britain, the Republic of Ireland, and several European nations.

The article "Exploring 136 kHz" by Peter Dodd, G3LDO, appears in the November 1998 issue of QST. It discusses practical equipment and an antenna system for the allocation. Dodd also is the editor of the LF Experimenter's Source Book (2nd ed) published by the RSGB and available from the ARRL for $14. Order Item 7148. Visit ARRLWeb, for details or call, toll-free, 888-277-5289.

A special CW LF operation from the Netherlands is scheduled for November 14 at 0900 UTC at 136.5 kHz using the call sign PA2NJN (see In Brief item, "Netherlands LF test" below). The operation will run 150 W to a wire antenna, tethered to a kite at about 920 feet in the air.

A copy of the full ARRL petition PDF file is available on ARRL's web site, at

There is also a Plain Text Version

Regarding 73 kHz
On 29th April 1996, the British government announced that UK radio amateurs could use the band 71.6 - 74.4 kHz.

The impetus came from amateurs who want to experiment with LF communications through rock into caves. Activity is not limited to cave communications, however, and any Class A licensee will be able to use up to 1 Watt ERP with any suitable mode.

These Web pages were written in the days following this announcement, but have not recently been updated. For now, they are kept here as reference material only. The FCC in the U.S. is apparently mulling over the idea of allowing more privileges at160-190 kHz. As news comes out about further expansion of VLF operating privileges in various countries I will try to add them here
- Brian Carling, AF4K.

NEWS OF NOTE: It is reported that radio amateurs in the United Kingdom are looking forward to ANOTHER new VLF band! The Radiocommunication Agency has announced that it hope to release the 136 kHz band to all UK Class A licensees early in 1998. Like the 73 kHz band, the new allocation will be a narrow sliver. In fact, at only 2.1 kHz in bandwidth, it will be slightly smaller than the 2.8 kHz available at 73 kHz. The RSGB says that the band will likely run from 135.7 to 137.8 kHz


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