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![Previous (earlier) Story](/images/sty-down.gif ""Running" a Marathon: the K1M Special Event"){kind=small} Previous: "Running" a Marathon: the K1M Special Event |  Next: Ohio Youngsters Enjoy First ARISS School Group Contact of 2004 |
By Anthony A. Luscre, K8ZT
Contributing Editor
January 6, 2004
When the sunspots and the thermometer drop and the daylight hours grow short, it's time to explore the low bands. You might be surprised at how well QRP can work there.
The "Low Bands"
For purposes of this month's column, we'll define the "low bands" as 160 through 30 meters. These bands compose the bottom third of Amateur Radio's HF allocations--frequencies from 1.8 MHz through 10.15 MHz. Although we're grouping these four bands, each has its own distinct characteristics.
The upper two bands--40 and 30 meters--already are favorite haunts for many QRPers. Some of the reasons include the around-the-clock band openings and less seasonal variation in propagation. Homebrew equipment construction is easier and more stable on 40 and 30 than it can be on higher bands, simple antennas can be very effective and a plethora of monoband and multiband QRP transceiver kits is available for 40.
FCC regulations governing 30 meters also make this a band that favors low-power operation: The maximum allowable output power for all stations is capped at 200 W PEP, and only non-phone modes are permitted--CW, RTTY and data, with a maximum sending speed of 300 baud.
Unfortunately, the lower two bands--160 and 80 meters--have a reputation of being difficult or impossible to use for QRP beyond very local communications. While it's true that these bands pose significant challenges for the QRPer--including greater signal absorption and background noise, not to mention larger antenna requirements--it's still possible to enjoy very successful QRP contacts on 160 and 80 meters.
Low-Band Propagation
The low bands are often referred to as nighttime bands. Lower-frequency (ie, longer wavelength) signals, especially on 160 and 80 meters, are absorbed during the day by the highly charged D Layer. This means little or no signal reaches the F-2 layer for further propagation during daylight hours. On 40 and 30 meters, however, absorption is not as severe, and daytime short-distance skip via the E and F layers is possible.
At night the D Layer dissipates, and skip distances on the low bands can increase dramatically. The lower bands also can exhibit great propagation enhancement at dusk and dawn. This phenomenon is known as "gray-line" enhancement. Gray-line effect is most pronounced when the stations at both ends of the QSO are situated along the terminator between daylight and darkness on Earth's surface.
If you really want to be successful on the low bands, you need to study their propagation characteristics, follow the gray line on maps or software and know sunrise and sunset times around the world. Unfortunately, it's not possible to do more than simply scratch the surface here in terms of explaining propagation. For more detailed information about propagation and explanations of propagation phenomena, visit the Propagation page on the ARRL Web site and the associated links to other articles and resources.
Other Web sites dealing with propagation include Ed Jones, AE4TM's Basics of Propagation, Top Band Propagation, Rod Dinkins, AC6V's The Propagation Pages and "The 160-Meter Band: An Enigma Shrouded in Mystery".
30 Meters
All digital (mostly CW) all the time, no competition from kilowatts, no contesting and a more-relaxed operating style all contribute to making 30 meters a favorite band for many QRPers. Toss in propagation characteristics somewhere between those of the high and the low bands and you get a band for all seasons. On the downside, 30 meters is a comparatively small (only 50 kHz) and non-exclusive amateur allocation that can be afflicted by intermittent (and sometimes non-amateur) QRM. (Because it's a secondary allocation, amateur users of 30 meters must avoid interfering with any primary users of this band.)
 The Rockmite transceiver kit for 40 meters from Small Wonders Lab. For $27 and a few hours assembly can you get on 40 meter QRP and probably work some DX too. |
40 Meters
If you want to meet other QRPers, this is the band. Tune in the vicinity of 7040 kHz, the 40-meter QRP calling frequency, almost any time of day or night and you will probably find other low-power operators. (This is also a calling frequency for digital mode--such as PSK31 and RTTY--DXing, since hams in other parts of the world only have 7.0 to 7.1 MHz for a 40-meter band. We'll have more to say on that issue later.) QRPers often search and pounce, avoiding calling CQ. Try calling CQ on or near the calling frequency, however, because there will be no QSOs if everyone just listens. Many QRP rock-bound (crystal-controlled) rigs are tuned to 7.040.
Unless you're specifically looking to hook up with other QRP ops, there's no special reason to restrict your 40-meter QRP operation to 7040 kHz. Much, if not most, of the DX on 40-meter CW is found in the lower 20 to 25 kHz of the allocation, and often at or near the very bottom of the band (ie, 7000-7005 kHz or so). This is, of course, where having that Extra class ticket comes in handy. With a decent antenna, you should find that plenty of DX stations will come back to your low-power signal.
Adjusting listening habits also can help when
attempting to work lots of DX stations with QRP. DX conditions are most
favorable in the evening, night and dawn, during the late fall and winter
months and during declining sunspot years like the one we're in now. Just as on
the higher bands, propagation usually moves west with the sun. Unlike the
higher bands, 40-meter propagation usually trails the sun by a few hours. A few
"quality" hours of listening late at night and just before dawn will amaze you
as you hear--and possibly work--ZLs, VKs and JAs from the Midwest.
 During the pre-computer era, The DX Edge, a popular propagation tool, provided gray-line information using month-specific plastic overlays. DX Edge was manufactured by Xantek but is currently not available so keep your eyes open at hamfests for this item or its earlier monochrome version. |
Because the 40-meter amateur allocation varies between ITU Regions 1 (Europe and Africa) and 3 (Asia/Oceania) and Region 2 (the Americas) there are no common QRP frequencies for SSB contacts. Operators throughout the Americas--QRP or QRO--typically use split-frequency operation to work 40-meter SSB DX. Working "split" requires that you have either two VFOs or a separate receiver. This does raise the stakes in terms of working SSB DX on 40 meters, but once you try working split, you'll find it's not only quite easy but may work in favor of your low-power signal.
An excellent time to make contacts on split is during the worldwide phone contests when DX stations are actively looking for contacts. To work 40-meter SSB DX, switch to LSB mode and listen in the 7030 to 7090 kHz range for DX phone transmissions. Operators will give their listening frequencies, usually above 7150 kHz, in the US phone band.
Leaving your first VFO (A) or your separate
receiver on the listening frequency, switch to your second VFO (B), and tune to
the announced listening frequency. Check to make sure you will not interfere
with other stations that may be operating simplex on the listening frequency.
Follow your transceiver's instructions to set your radio to split operation,
listening with VFO A (or on your separate receiver) and transmitting on VFO B.
 ON4UN's Low-Band DXing (3rd ed), the book for making the most of the low bands. |
 DXing on the Edge by Jeff Briggs, K1ZM, has history and hints for 160-meter operators. |
 This sample of the K8ZT log during the 2003 CQ WorldWide DX contests show what 4 W to a modest vertical antenna can do. |
Unfortunately, there are two additional challenges on 40 meters. The band in the rest of the world is small--just 100 kHz--and quickly becomes crowded during a contest. In addition, AM broadcasters inhabit the upper portion (7100-7300 kHz) of the band, transmitting with tens or even hundreds of kilowatts. Fortunately, action taken during World Radiocommunication Conference 2003 (WRC-03) last summer will provide some relief by increasing the 40-meter allocations in Regions 1 and 3 to 7200 kHz and moving broadcasters above 7200 kHz in 2009.
80 Meters
Offering typical daytime distances of up to 300 miles, 80 meters can be a very reliable band for local and statewide communication. Eighty is a favorite for statewide and regional nets, too, including both traffic and rag chewing nets. With a lot more available spectrum, 80 is free of the sort of congestion that can plague 40 meters.
160 Meters
Know as "Top Band" and "The Gentleman's Band," 160 meters has a different "feel" than other HF bands. By informal agreement, CW activity usually takes place from 1800 to around 1840 kHz. Many--but not all--contests include 160 meters, but operating there often is more relaxed and casual. Higher noise levels on this band mean the most successful operators use a separate receiving antenna--often a "Beverage" antenna--and the majority of operation takes place during the fall and winter months. Due to the size of a full-sized antenna and the narrow usable bandwidths of smaller "compromise" antennas for this band, many hams avoid 160 altogether. Next month we will look at some antenna solutions that can allow most hams to give this band a whirl.
Reference Materials
Known as the definitive book on the subject, Low Band DXing by John Devoldere, ON4UN, is packed with information on propagation, antennas, equipment and operating techniques on the low bands. Also, check out DXing on the Edge by Jeff Briggs, K1ZM, a notable DXer and Top Band op.
Reader Feedback and Author Comments
I have a suggestion for a late, but very easy to keep, new year's resolution: Make plans to visit one or more of the many QRP conferences scheduled for 2004. The first big get together is Atlanticon in Baltimore in March, followed by Ozarkcon, Four Days in May held in conjunction with Hamvention and many more.
There's a complete schedule of events for 2004 on my Web page's QRP Get Together Schedule. If your QRP group is sponsoring an event that is not listed, please e-mail the information to me, and I can add your event to the calendar.
Editor's note: Anthony Luscre, K8ZT, an ARRL member, lives in Stow, Ohio. He has
worked in the field of medical microbiology for 18 years and is now a
Technology and Computer Coordinator for a local school district. Luscre is an
avid QRP operator having earned DXCC, WAS and WAC using no more that 5 W
output. Readers are invited to contact the author via e-mail, k8zt@arrl.net
and to visit his Web site.
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