1. The Mystery Band by Marc C. Tarplee, Ph.D. N4UFP
6 Meters
The Mystery Band
by Marc C. Tarplee, Ph.D.
N4UFP

2. 6 Meters: Rhetoric vs. Reality
No one is on 6 meters
(I’ve made over 1900 QSO’s on 6 m since 1992)
There is no DX on 6 meters
(I’ve worked 46 states and 38 countries on 3 continents)
6 meters is the TVI band
(I have never had a TVI complaint from my neighbors)

3. What makes 6 m interesting?
A wide variety of operating modes is available
No band offers a wider range of propagation phenomena than 6 m
Station equipment requirements are modest
Antenna experimentation is much easier on 6 m than the HF bands

4. 6 Meter Band Plan
CW, beacons (beacon sub band = MHz)
SSB, CW (SSB calling frequency = MHz)
DX window
All modes
Nonvoice communications (digital calling frequency = MHz)
Radio remote control (20-kHz channels)
Pacific DX window
Repeater inputs (19 channels, digital repeater inputs are MHz)
Repeater outputs (19 channels, digital repeater outputs are MHz)
Repeater inputs (except as noted; 23 channels)
52.02, FM simplex
TEST PAIR (input)
Repeater output (except as noted; 23 channels)
Primary FM simplex
Secondary FM simplex
TEST PAIR (output)
Repeater inputs (except as noted; 19 channels)
Remote base FM simplex
Simplex
53.1, 53.2, 53.3, Radio remote control
Repeater outputs (except as noted; 19 channels)
53.5, 53.6, 53.7, Radio remote control
53.52, Simplex

5. 6 Meter Propagation Every type of propagation is possible on 6 m:
Line of Sight
Tropospheric Propagation
Sporadic E
Meteor Scatter
Auroral Scattering
Transequatorial F
Ionospheric F2

6. Line of Sight (LOS) and Tropospheric Propagation
LOS coverage is determined primarily by the height of the transmitting and receiving antennas
For typical amateur 6 m stations LOS coverage is about 20 miles
LOS propagation is unaffected by solar conditions, time of day or the seasons
Tropospheric Propagation
Variations in the humidity of the troposphere cause RF to be scattered over the horizon. This is known as tropospheric scatter
Temperature inversions (warm dry air located above cool moist air) refract RF in the VHF range back towards the earth. Temperature inversions occur daily in the middle latitudes at sunrise and sunset. Communications are possible over a ranges up to 600 miles
Over the oceans, stable temperature inversions can create a duct, through which VHF can travel without significant loss up to 2500 miles

7. Tropospheric Scatter
Tropospheric Ducting

8. Sporadic E (ES)
Clouds of high density ionization form without warning in the ionosphere’s E layer
ES is not dependent on solar activity. It may occur any time, but is most frequent between May and August, with a smaller peak of activity in December
Single hop ES has a range of ~1400 mi
Double hop ES has a range of ~ 2500 mi
Cause of Sporadic E is not known: high altitude wind shear may be responsible.

9. Sporadic E (ES)
The ionized clouds that cause sporadic E propagation can move. This animated sequence shows grid squares contacted in ½ hour intervals during an ES opening beginning at 0500 Z, 10 June 2001

10. Meteor Scatter
As meteors are vaporized in the upper atmosphere, they leave behind ionized trails at heights of 60 – 70 miles that are sufficiently dense to reflect VHF
A long trail lasts only 15 seconds so contact must be made quickly on SSB
SSB QSO’s via meteor scatter are usually possible only during a meteor storm
Short trails that occur continuously may be used for high speed CW QSO’s (> 100 wpm)
Best time for meteor scatter is after midnight or during a meteor storm

11. Aurora (Au)
During periods of intense auroral activity, charged particles in the auroral zone can scatter 50 MHz RF
The RF interacts strongly with the aurora, resulting in significant distortion of the signal. Only narrow band modes such as CW are used during Au openings
To work Au, the transmitter and receiver point their antennas at the auroral zone, not each other.

12. Transequatorial F (TE)
The ionosphere’s F layer is most intense in the region of the geomagnetic equator.
Stations within about 2500 miles of the geomagnetic equator can launch 50 MHz RF into these regions. The RF is refracted and travels across the equator and into the other hemisphere without scattering from the ground
Stations using TE must be at approximately equal distances from the geomagnetic equator

13. F2 propagation
Communications over long distances (> 2000 miles) are possible on 6 m via the F2 layer of the ionosphere during periods of high solar activity (solar flux above 220)
Openings generally occur in spring and fall during daylight hours (similar to 10 m)

14. Propagation Example
2001 June VHF QSO Party 6 m QSO’s

15. Traditional 6m Operating ModesCW
Used primarily below MHz
Used during auroral openings – narrowband modes like CW are less susceptible to distortion
HSCW
CW sent at high speeds (200 wpm or more)
Used with meteor scatter propagation
Most operation takes place near MHz
SSB
Most common 6m mode - USB is the standard
Calling frequency is MHz
– MHz is the DX window

16. Digital 6m Operating Modes
FSK441
Uses triplets of 4 tones to transmit data
882, 1323, 1764, 2205 Hz
Each character is sent as a 3 tone sequence
43 Character alphabet (letters, numbers . , / ? # $ <sp>)
Single tone characters used for shorthand messages:
882 Hz - R Hz - RRR
1323 Hz – R Hz - 73
Data rate = 147 characters per second (3 tones/char)
Used for meteor scatter communications
Most activity takes place near MHz
Messages sent in 30 sec intervals – westernmost station transmits during first 30 seconds of each minute.

17. Digital 6m Operating Modes
JT65B
Narrowband PSK
64-ary PSK (6 bits per baud)
~2.7 Baud signaling speed
~5.4 Hz operating bandwidth
Requires a stable receiver, good timing
Messages sent in 60 sec intervals – westernmost station transmits during even-numbered minutes.
Provides clear copy at SNR < 0 dB
Used for moonbounce and troposcatter operation
Most activity takes place near MHz

18. 6 Meter Station Requirements
Transceiver or Transverter
RF output of at least 10 W PEP (>100W for FSK441, JT65, ~1000W for EME) with multi-mode capability (CW/SSB/FM)
ICOM 706, 746, 756
Yaesu FT-100, 817, 847, 920
Kenwood TS-570
Alinco DX-70TH
Antenna
Gain of at least 5 dBd (> 15dBd for EME)
Should be rotatable (az-el rotation is very important for EME)
Should be at least 20 ft above ground
Use low loss coax (RG8 up to 75 ft, Belden 9913 for longer runs)
Useful accessories
RF pre-amp (RF switched)
Grid Square Map
PC (for FSK441, JT65)

19. 6 Meter Antennas
6 m antennas are relatively small, light and easily rotatable.
Best choices for a new operator:
2 element quad
3 element Yagi
Extended Double Zepp
6/10 dual band dipole
For weak signal work (CW/SSB) the antenna should be horizontally polarized
For repeater operation, vertical polarization is the norm
For EME an array of 4 long yagis is typical
Meteor scatter operation requires an antenna with good gain and broad beamwidth – 5 to 9 element yagis work well.

20. 6 Meter Quad and Yagi Antennas
2 element Quad (square loops of #14 ins. wire Z ~ 60 ohms Gain ~ 4 dBd)
Element Loop Length (in) Position (in)
Reflector
Driver
3 element Yagi (Aluminum tubing Z ~ 42 ohms gain ~ 5 dBd)
Element Half Length (in) (0.75 dia dia) Position (in)
Reflector
Driver
Director
5 element Yagi (Aluminum tubing Feed Z ~ 35 ohms Gain ~ 8 dBd)
Element Half Length (in) (0.75 dia dia) Position (in)
Reflector
Driver
Director
Director
Director

21. Other 6 Meter Antennas Dipole Extended Double Zepp
Length = 114 inches (#14 wire) Z ~ 70 ohms Gain ~ 0 dBd
Extended Double Zepp
Length = 282 inches (#14 wire) Z ~ 45 ohms Gain ~ 4 dbd
Antenna is fed at the center through a inch length of 450 ohm ladder line (VF = 0.9)
6/10 dual band dipole
Length = 198 inches (#14 wire) Z ~ 64 ohms Gain ~ 1 dBd
Antenna is fed at the center through 32 feet 4 inches of 450 ohm ladder line (VF = 0.9)
Antenna also can be used on 10 meters (Z ~ 72 ohms)

22. 6 Meter Activities Contests Operating Awards Grid Square Hunting
ARRL January VHF Sweepstakes (3rd weekend in January)
ARRL June VHF QSO Party (2nd weekend in June)
SMIRK QSO Party (3rd weekend in June
CQ WW VHF Contest (2nd weekend in July)
Six Club 6 m Sprint (3rd weekend in July)
ARRL September QSO Party (2nd weekend in September)
Operating Awards
VUCC – contacts with 100 Grid Squares, not difficult
WAS – tough, but not impossible
DXCC – very tough from North America, but it has been done
Grid Square Hunting
There are over 500 grid squares in the continental US
No one has worked them all yet (except perhaps for W5FF)

23. What is a Grid Square?
Almost all VHF operating awards and contests involve grid squares
Grid Squares are 2º longitude x 1º latitude sections of the earth’s surface (there are 32,400 in total)
Each grid square has a 4 character designator containing 2 letters and 2 numbers.
The two letters designate the field. There are 324 fields lettered AA through RR
Each field is divided into 100 squares numbered 00 through 99
The continental US includes grid squares in fields CM,CN, DL, DM, DN, EL,EM,EN, FM and FN
Most of Rock Hill is in grid square EM94.

24. World Grid Fields

25. Grid Square Map of the USA