THE SIX METER AMATEUR RADIO BAND
FREQUENTLY ASKED QUESTIONS
(Designed to help encourage hams to use and enjoy this band!)
By Randall Rhea, KG0HW
Updated: February, 1997
"We do these things not because they are easy, but because they are hard."
- John F. Kennedy
WHAT IS THE SIX-METER BAND? Kennedy may not have been talking about
the 6 meter band, but he might as well have been. If you like a
challenge, this is it! If you want reliable, easy, worldwide
ham radio communication, stick to 20 meters. If you enjoy a
challenging band that changes moment to moment, 6m is for you!
The 6 meter band is a portion of the radio spectrum around 50 MHz
allocated to amateur radio. What attracts hams to this unusual band?
It is fascinating because just about all types of propagation pop up
on 6m at one time or another: Sporadic E (Es), Tropospheric Ducting,
Aurora, Meteors, even F2 skip like an HF band... they're all here.
6m is an acquired taste: a few hams work the band regularly, but many hams
never work it at all. Once you acquire the taste, you tend to be
hooked for life. The band has become more popular in recent years,
thanks to several new 6m-capable radios. There two types of 6m
operators: the ones who use FM or packet for local work, and ones
who work DX with SSB. (Some like me even do both!)
WHAT ARE THE FREQUENCIES? In the U.S. and some other countries, the
six-meter amateur radio band lies between 50 and 54 MHz, just below
TV channel 2 in the U.S. In some other countries, 6m is allocated
much less bandwidth. New Zealand's band starts at 51.0. Check your
allocations for your particular country. They change pretty often as
the band is becoming more popular.
WAS 6M ONCE TV CHANNEL ONE? Televisions in the U.S. start at channel
2. Some ham books say that 6m was once channel 1. This is not true.
Just after WWII, Channel 1 in the U.S. was allocated 44 to 50 MHz,
with 6m occupying the same spot as it does today. By 1948,
interference from police radios and hams made channel 1 nearly
unusable. Early TV sets had little or no RF shielding. The ARRL
recommended that channel 2 (54-60 MHz) be eliminated, but the FCC
decided to axe channel 1 instead.
IS FM USED ON 6M? Yes, usually above 52 MHz. The level of activity
varies with the area. Its popularity is on the rise thanks to
several new all-mode 6m rigs on the market. The main FM simplex
frequency is 52.525 MHz. Your local range is better on 6m than on 2m
with the same power and a similar antenna. If 2m is too crowded in
your area, the FM portion of 6m may be just the solution you need. Most
6m enthusiasts, however, use only SSB or sometimes CW.
ARE REPEATERS USED? There are a several 6m repeaters listed in the
ARRL Repeater Directory, but some of them are not operational. This
will depend on your area. The offset in the U.S. is usually one MHz.
(e.g. 53.330 out, 52.330 in) I would listen to the FM portion of 6m
to check for activity in your area.
HOW DO I KNOW IF THERE IS A DX OPENING? Of course, the best way is
to check for an opening is to listen to 6m. Many beacons operate
around the world between 50.0 and 50.1 MHz; check the ARRL Repeater
Directory. Monitor 50.110 and 50.125 for SSB openings. You can also
monitor 28.885 MHz, the "10 Meter VHF Liaison Frequency", where hams
report VHF openings and schedule contacts. You'll hear some of those
"pros" you see in QST with the huge antenna farms like W5UN (the first
ham to work 100 countries on 2m!) on that frequency.
WHAT ARE THE MOST POPULAR FREQUENCIES? Per the FCC, 50.0 to 50.1 is
reserved for CW work in the U.S. Most operation is SSB. 50.110 is
the most popular SSB DX frequency, and 50.100 to 50.124 should be
used only for DX. Some hams tend to discourage (or flame) U.S.
domestic stations from calling CQ in this "DX window". The other
popular frequencies tend to vary from area to area, so the following
is only a general guide for beginners: 50.125 is the U.S. domestic
calling frequency, and most domestic SSB is found between 50.125 and
50.200. Only during hot F2 openings do you find SSB above 50.200.
DO I NEED A BEAM ANTENNA? If you want to win contests, yes. You can have
fun with a vertical during openings, (I do with an Icom 706 in my
car) but the pros use beams. Most serious operators are horizontally
polarized, but cross-polarization does not matter for Es, F2, or Aurora.
A few stations use 3-element beams, but a 4 or 5 element beam is so small
that a LOT of people use them. Quite a few people have Cushcraft 6-
element "Boomers". There are a few other big beams, and the lunatic
fringe stacks them. For example, K6QXY has a stack of 4 six-meter
beams, each with a 50ft (15m) boom.
HOW HIGH SHOULD MY ANTENNA BE? For sporadic E (Es) openings, a
height of about 30 feet is optimum according to studies. For tropo
and other modes, the higher the tower the better! Some people have
multiple antennas at multiple heights to work different kinds of
propagation modes. I live in subdivision where no outdoor antennas
are allowed, so I use a 2-element beam in the attic, and it works
pretty well. I also use a vertical for local FM work. RG8 or RG213 is
plenty good enough cable for most people. Antenna-mounted preamps are never
needed.
IS 6M NOISY? External noise is fairly high at 50 MHz. It overrides
the front-end noise figure on about all the rigs on the market today
unless you have a LOT of cable loss or a VERY quiet location.
IS THERE PACKET WORK ON 6M? It depends on the area. Local packet
work can be found in the higher frequency portions of the band.
There has been very little DX packet work.
CAN I RUN RADIO-CONTROLLED EQUIPMENT USING 6M? This is legal in the
U.S. for licensed hams. Check the ARRL Repeater Directory for
suggested frequencies.
WHAT ARE "GRID SQUARES"? On VHF and up bands, the world has been
divided in 1-degree latitude x 2-degree longitude "squares" which
start at the south pole and date line and "read right up". SSB stations
will always identify their grid square along with their call sign, e.g.
"KK6MY DM87". Each square is also divided into sub-squares. European
stations like the subsquares; most US stations don't even know their
own. In any case, the "squares" and their VUCC awards have been a
wonderful interest builder, and have kept the QSL printers in
business! Check the ARRL Operating Manual for a map of the grid
squares.
WHAT RIGS ARE USED? The rig selection has improved significantly
in recent years. After the golden years of 6m AM radios in the
60's, the market dried up in the 70's. Today, several manufacturers
offer excellent 6m rigs. Probably 50% of the active stations have
80 to 150 W output, either from old Icom 551D s (the 551 is 10W), or
from solid-state (brick) amplifiers following the many types of 10W
rigs, such as the Yaesu Ft-620B or the Kenwood TS-600. The Icom 575H
is very popular, as it has an excellent receiver and 100 watts (the
575A is 10 watts). HF rigs that add 6m (such as the Icom 726 or 706)
can be effective but usually lack receiver sensitivity. Perhaps 40%
of the stations run just 10 to 20 W, but most serious operators run
higher power. The remaining 10% have tube rigs such as the Drake
TR-6. Good 6m rigs tend to be expensive, even on the used market.
Swan and Heathkit tube rigs are the least expensive and can be quite
usable, but you will run into problems typical of older rigs, such
as drift (especially on the Swan). The kilowatt is rare on 6m: such
high power sometimes does not help and causes terrible TVI. The
norm for serious stations is 100 to 150 watts, but you can have a
lot of fun with a lot less power. Expect to see inexpensive SSB 6m
rigs from companies like MFJ as we approach the next sunspot peak,
which is due around 1999.
WHAT ABOUT THE NEW ICOM 706? Icom, Alinco, and Kenwood now offer
small 6m all-mode rigs designed for the mobile ham. I have an Icom
706 in my car, and I love it. I can now monitor and work 6m
whenever I drive. The 706 is quite an amazing rig, considering it
has 100 watts for 6m and also covers HF and 2m. Although it has
weaknesses (intermod, dynamic range, phase noise) typical of its
price class, its receiver is surprisingly good for a radio of its
size and price. It is not a main rig for the "pro" 6m operator, but
a great mobile companion to your base station.
CAN I USE A TRANSVERTER WITH AN HF RIG TO GET ON 6M? Yes. A
transverter allows you to use an HF rig on 6m (or other VHF/UHF
bands). Many 6m operators swear by the transverter + HF rig + brick
amplifier setup. Keep in mind, however, that some of the
transverters are kits, and most HF rigs must be modified to support
transverters. In these cases, some experience with electronics is
necessary. The results are well worth it. The top-of-the-line
transverters are from a German company called SSB Electronics. They
outperform 6m rigs but are expensive. Down East Microwave and Ten
Tec also sell very popular assembled and kit units. If you already
have an excellent HF rig, the transverter is a great way to go.
Keep in mind that mediocre HF rigs may produce mediocre results.
I LISTEN TO 6M OCCASIONALLY, BUT I NEVER HEAR ANYONE. Openings on 6m
are rare, especially during low points in the sunspot cycle. For
hams in far northern latitudes (say 50 degrees and above), aurora
openings are common. The most common openings in middle and southern
latitudes are a result of sporadic E (Es), which occurs most often
in June. F2 openings occur only when the solar flux is high. The
frequency where you are most likely to hear someone is 50.125 USB.
An explanation of the many types of propagation on 6m follows.
HOW OFTEN ARE THERE F2 OPENINGS? F2 propagation, the kind that we
know and love on 20 meters, occurs rarely on 6m. Only at the peak
times of the sunspot cycle, a few years out of each eleven, does the
band open up for F2. When it does happen, the band becomes a frenzy
of activity, and behaves similar to 10 meters. In the last cycle,
there were many openings in 1989 through 1991, but that cycle had an
unusually long period of peak activity. Cycles average 11 years,
but the last peak happened only 8 years after the previous one.
Openings occur most often in Autumn during the daytime. A few
stations have worked 100 or more countries, but they have been
patiently working the fleeting openings for many years. The March,
1993 QST magazine has an excellent article on 6m propagation that
shows a correlation between solar flux and openings.
HOW IS TROPO PROPAGATION ON 6M? The ordinary ground-wave
tropospheric ducting range on six isn't quite as great as on 2m.
There are a number of reasons. Since there are so many other
propagation modes on six, people don't try very hard on tropo. Antenna
gain often is higher on two. Noise is lower on two. At least in the
summer, stations like W3BWU (Pittsburgh), W3IDZ (northern NJ) are
easily worked from Maryland with the beam pointing at them, and can
be heard at almost any pointing. They are in the 150-W class.
HOW IS METEOR PROPAGATION? Any area workable by meteors can be
worked more easily by Es or aurora. Even though meteor bursts are
much stronger and longer on six than on two, little use has been made
of them. There has been a VERY little meteor-burst packet work on
six. W3OTC had the first such contact (with W0RPK). W3XO worked him
a few years later.
WHAT ABOUT IONOSCATTER? Some people think it's really meteors, but
every weekend morning there are a number of nearly- kilowatt
stations working each other on SSB at distances of about 600 - 1000
miles by ionospheric scatter. Sigs are weak, and it takes good
beams, height, and power, but it is very reliable. See the old NBS
papers by Bailey, Bateman and Kirby, et al. Bateman and Kirby
were/are hams. Ross Bateman recently died. Dick Kirby continues as
head of ITU in Geneva.
HOW IS AURORA? It is much easier than on two. SSB is usually
intelligible, but CW is easier to work. Point north about dusk,
most commonly in March and October/November. (In northern Europe,
hams report Aurora peaks around dusk and again around midnight.)
Lots of people in the far northern latitudes work this mode when it
happens. Aurora can occur as far south as the mid-U.S. during bad
solar storms. The March, 1989 storm was so powerful that Aurora was
visible in San Francisco and power was knocked out all over Canada.
WHAT ABOUT SPORADIC E (Es)? Es is the most common propagation mode
on 6m. The term "sporadic" is accurate: stations can pop in and out
and then fade quickly. Studies (see March, 1993 -QST- Magazine) have
shown that Es has nothing to do with the sunspot cycle; it is much
more a function of the time of year. Es can occur anytime, but is
most common around the solstices (June 21 and December 21). In the
southern latitudes, the peak occurs around Christmas with a minor
peak in June. The northern latitudes find peak times in June and
July with a minor peak at Christmas. February is the low point, but
this year (1996), we even had a good opening then. In addition to
the common single-hop range of 500 - 1500 miles, there are quite a
few double- and-more hop contacts on 6m. Now that a number of
Europeans are on six, we find that they can be worked from the US
east coast each summer. Likewise the Caribbean stations work all
over the US. The US west coast can work Hawaii, Alaska, and Mexico.
You will also hear some hams on June DXPedition trips to Mexico and
the Caribbean; they are easy to work in the late afternoon or early
evening, even with 10W and a vertical. The VHF contest in the middle
of June is also a good time to work Es.
HOW SHOULD I LOOK FOR SPORADIC E (Es)? Within two weeks of the
Winter and Summer Solstice (June 21 and December 21), you should be
monitoring 50.125 as often as possible; this is the most common time
and frequency for Es. I would also check 50.110, 28.885 MHz, and CW
beacons between 50.00 and 50.100. 10 meters and the 27 MHz
Citizen's Band are good indicators of 6m Es: If you hear Es on 10m
and the stations are less than 1000 miles away, it's time to check
for Es on 6m. If the stations on 10m are 500 miles away, you can be
virtually certain that 6m is open. Likewise, a station on 6m from
500 miles away means Es on 2m is possible.
WHAT ABOUT TRANSEQUATORIAL PROPAGATION? - The southern US gets a
number of openings to South America by some kind of
ionospherically-ducted propagation. The stations are generally about
equidistant either side of the magnetic equator. Given exceptional
luck, an Es opening linked into this mode can make it available to
more northern stations. This mode has bad flutter fading and a touch
of the auroral spectrum spreading. This mode also works sometimes on
two meters if you use CW and really good gear. It has been worked on
432 MHz.
ANY MOONBOUNCE (EME)? - There have been a few EME contacts on six,
but the required antenna size and high background noise makes it out
of the reach of most people.
WHAT ABOUT TVI PROBLEMS? There is no doubt about it, six has TVI
troubles. You don't find a lot of people on 6m in channel 2 areas
unless cable is widely used. VCRs are very prone to 6m pickup. Some
cordless phones, baby monitors, and kiddle walkie-talkies
operate on 49 MHz. Most consumer electronic equipment has poor RFI
shielding. The common connecting or power cable is a quarter-wave
antenna for six. The TV owners have their revenge since the 13th
harmonic of the color subcarrier, or something, of TV sets and TV
games puts out a birdy at 50.113 MHz to bother the 6m operators in
return. There is also quite a bit of trouble from noisy power
distribution lines if they aren't buried (usually bad insulators or
poor guy bonding). I would get a book on curing TVI. Often, using
snap-on ferrite filters on any cables (patch cords, power cords) of
home electronics equipment can help, and these are inexpensive and
available at Radio Shack.
WHERE ARE GOOD WEB SITES TO FIND OUT MORE INFORMATION? The best
6m web site I know about is the UK Six Meter Group:
http://www.uksmg.com
ABBRIEVIATIONS USED
2m: The Two Meter Band (144 MHz)
6m: The Six Meter Band (50 Mhz)
10m: The Ten Meter Band (28 MHz)
ARRL: American Radio Relay League
CW: Continuous Wave (Morse Code)
DX: Long-distance communication, usually with another country
EME: Earth-Moon-Earth (bouncing signals off of the moon)
Es: Sporadic E Propagation
MHz: Megahertz (1,000,000 cycles per second)
SSB: Single Sideband, a form of AM voice communication
TVI: Television interference
VCR: Video Cassette Recorder
USB: Upper Sideband, a form of SSB
VHF: Very High Frequency (30 MHz to about 200 MHz)
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