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It's hard to believe that the October QST has arrived already in my mailbox and on line at the ARRL website. The hard to believe part is not really the arrival of the magazine in mid-September. The thing that surprises me is that October is just over the horizon. October! The entire ham radio dynamic changes in October, because the seasons are changing, and here in North America we are about ready to jump up and down in anticipation of some really excellent HF band conditions.
Here's the thing. By the time October rolls around, the northern hemisphere days are seriously shorter. Shorter days mean less daylight which also means less solar heating and less convective thunderstorm activity. Fewer thunderstorms mean less radio interference, so we can start using the lower frequency HF bands for even long-distance contacts, even DX. Every HF band benefits by less thunderstorm-generated interference, though.
If you want to talk DX, the higher frequency HF bands will really be hopping. The solar cycle is nearing peak, which may happen next year, and that make the coming Autumn and Winter months prime time for DX. You will have a chance to work stations you have never heard before on bands like 15 meters and 10 meters that may have seemed mostly dead for as long as you can remember. If you are a new ham and have not experienced the fun of DX during a sunspot maximum, you are really in for a treat. When the conditions get really good the bands open up for clear communications with very little power. Even if you have a very modest station with a dipole or vertical antenna and no linear amplifier you can still work DX. A solar maximum levels the playing field and opens up the bands!
There are some special considerations to working DX. The first rule is to listen, listen, listen. It is easier to call a DX station than to expect to be called by a DX station, at least if your goal is to work DX. Another reason to listen carefully is that a DX station may be calling on a frequency that is not available to USA stations but listening on another frequency. This kind of split operation is fairly common in working DX. Learn how to use the split function on your radio ahead of time. You will also want to listen for whether the DX station is calling for any particular type of station or whether they are calling only for stations in a specific geographic location. You will not want to return a call to a DX station if that station is calling for contacts in South America but you live in North America, for example.
You can call for DX yourself if you want. The way to do it is to call "CQ DX" several times, give your callsign, then listen and tune around a bit. If you are lucky enough to have a beam antenna, point it in the direction of the DX you would like to work. If you are new to the DXing game, you might want to acquaint yourself with beam headings for various parts of the world. It can be confusing if you have learned about the world from flat maps printed on paper instead of with a globe of the world. What appears to be "west" of your station in the USA might really be northwest, along what is called a "great circle" route. That fuzzy notion of where other countries are located comes from way back in your days in elementary school, and it might not be even close to correct. We want to point our antennas toward the DX. Here's a fun fact: We are here in Minnesota, and Minnesota is a northern state, sharing a border with Canada. Did you know that Paris is about as far north in latitude as that Minnesota-Canadian border? If I fly from Minneapolis to Paris, I will head northeast, over Canada and over the North Atlantic. If I fly from Minneapolis to Tokyo, I will fly northwest, and my path will be over Alaska!
Knowing great circle routes is a good DXing skill. You will also want to pay attention to band conditions that change as daylight and nighttime make their way around the globe. At the edge of the daylight, where day and night meet, there is sometimes an open pathway for DX. Being aware of alternate paths, even long path openings 180 degrees from the way you would expect to point your antenna, will help you rack up the DX contacts.
You will also need to be aware of time differences around the world. There are certain times of day when it may be more likely to hear stations from Europe. As you might expect, when people get off work and are relaxing during the evening hours they will probably have more time to get on the radio. Your opportunity to work European stations will come at a different time of day than when you are likely to hear Asian stations.
Third-party traffic is prohibited in many countries around the world. It is worth reviewing the list of countries with which the USA has third-party agreements if you are contemplating DX operation. The ARRL has a list, which you can locate using the excellent search function at ARRL.org. Just put third party into the search field.
Identifying your station is a bit different, too. You will want to identify at both the beginning and end of a series of transmissions as well as at 10 minute intervals. Many DX contacts are very short, and you will not need to worry about 10 minute intervals. Identifying clearly, using standard phonetics, is important. Non-standard phonetics have no place in DX operation and will do nothing but confuse the other operator, whose first language may not be the same as yours. Remember to identify your station in English if you are speaking another language during the DX exchange.
Sending and receiving paper QSL cards is still a part of DX operating, though less common than in decades past. Now that we have the Internet, Logbook of the World may be your choice. Some radio clubs have active DX managers who will collect your paper QSL cards and send them to the central location of the ARRL QSL Service, or you may use that service yourself. Awards are also available through ARRL and other groups. DXpeditions to remote places around the planet offer unique opportunities to work stations in really rare locations. DX news from ARRL, CQ, Worldradio, and a variety of other resources can help you stay up to date on what is available.
But back to October and the October QST. What reminded me about DX was that the October theme is "Special DXing Issue". You will want to be on the lookout for terms like "DX Spotting" and "Radiosport". "Zombie Bands" sure seems intriguing, too.
Email me at firstname.lastname@example.org with your questions & comments.
Patrick Tice, WA0TDA
Troubleshooting 101: Using an SWR meter to tune an antenna
As we prepare for the Autumn and Winter operating season, we turn our attention to antennas. Let's not wait until the snow is three feet deep and the wind is howling out of the north to get outdoors and make sure the antennas are working right!
A simple SWR meter, even a really cheap and cheesy one, can be a really helpful tool to help you diagnose antenna problems or to tune an antenna after its initial installation. Instrument-grade meters are not necessary here because we are really looking for relative readings and close is going to be good enough.
Here's a question for you: Which location is going to yield the most accurate reading when you are sampling SWR for purposes of making adjustments to the antenna? Is it out in the yard, closer to the feedpoint of the antenna, or is it in the ham shack with a long feedline attached between the SWR meter and the antenna?
The answer is that the less feedline you have between the SWR meter and the antenna, the more accurate the reading. But it is not always practical to have a transmitter and SWR meter outdoors, is it? Since we are really looking for relative readings anyway, we can still tune the antenna for the lowest SWR at the desired frequency of operation by taking readings with the SWR meter indoors at the ham shack. We must realize that the actual SWR may be somewhat different, but since we are tuning for relative minimum, so what?
The main problem with having the SWR meter indoors with the rig is that you have to make lots of back and forth trips indoors and out, outdoors and back in, as you trim or adjust the antenna then return to take the readings. If you prefer to get less exercise, you can opt for one of those "antenna analyzers" that allows you to generate a tiny low-level signal to determine where the antenna is resonant without the need for a separate transmitter and SWR bridge. These little gadgets are worth the money if you like to experiment with antennas. If you are an occasional antenna repair enthusiast, you might be able to borrow one from someone in your local club. It's a heck of a lot easier to tune an antenna in the field if you don't have to keep running back indoors to check meter readings.
Suppose you have installed a dipole antenna in the back yard and you have mounted it in an inverted vee configuration. This kind of antenna is tuned to roughly 1/2 wavelength on the frequency where it is to be used and fed with coaxial cable in the center. The feedpoint in the very center is elevated to the highest point and the two "legs' of the dipole trail down at an angle, each terminating at an end insulator and tied off high enough above ground to be out of the way and not be a tripping hazard. The inverted vee is nice for city lots because it only requires one really high point for mounting and the ends can be easily reached for tuning the antenna. It also takes up less space than a "flat-top" dipole antenna and will fit into city lots quite nicely. Once you have gotten the antenna more or less in place, you will find that it will likely not be resonant at the frequency you expected. It doesn't matter that you followed a formula. If you cut the antenna wires as is typically recommended, you allowed for a little extra wire on each leg of the antenna so that you would not come up short. Believe me, I have learned from experience that it is harder to lengthen an antenna that is cut too short than to carefully trim down one that is a little too long!
A symptom of an antenna that is cut too long is that the resonant point will be too low, perhaps even below the bottom of the CW portion of the band. This is a normal and expected thing to encounter when putting up a wire antenna for the first time, since you have allowed a bit of extra wire so that you could safely trim the antenna while doing the final tuning. When you "trim", you don't actually have cut any wire. Experienced antenna experimenters simply thread the end of each wire through one hole in the end insulator and fold it back onto the main wire, twisting it loosely on itself so that it can be undone and adjusted one way or the other after each meter reading. You don't need to actually wrap the end wire tightly or use wire clamps until you have satisfied yourself that the antenna is tuned the way you want it to be, with your favorite frequency at the point of resonance.
Sometimes you want to be able to move around the band, perhaps operating CW one day, then phone the next. A half-wave dipole will sometimes be usable with SWR readings of 2:1 or less across the entire band, and you may decide that the best strategy is to pick a frequency near the center of the band as you target a resonant frequency while you do your initial trimming. If you have an antenna tuner in your shack, you can lower the SWR enough to operate with your rig's full power even near the band edges.
The important thing to know about using an SWR meter or antenna analyzer is how to interpret your measurements. The shorter the antenna, the higher in frequency the resonant point will be. The longer the antenna, the lower in frequency the resonant point will be. When you take measurements at intervals from the CW end of the band through the middle and up into the phone band, you can plot a curve of SWR values. The bottom of the curve is the resonant point.
If you do this and find out that the resonant point is at the low end of the CW band and you are interested in operating SSB phone in the General Class portion of the band, you should say to yourself, "The wire is too long because the frequency of resonance is lower than it should be. Therefore, I will need to trim the antenna and then take another set of measurements."
By the way, don't even THINK about only trimming one leg of the dipole. Try your best to trim exactly the same amount on each leg, so as to avoid ending up with the feedpoint off center, which will mess up the tuning! (Remember that the predicted feedpoint impedance of a dipole is only going to be what you expected if the feedpoint is in the center!)
When you have satisfied yourself that everything is properly tuned, you can try hooking up the feedline to the rig in the ham shack and confirming your readings from inside. If that goes okay, return to the antenna site and finalize the installation, securing the ends and making sure everything is out of the way of anyone walking through the yard and making sure the entire antenna is solid enough to withstand those winter winds.
Handiham Net Update: The long-vacant position of Handiham Net Manager has finally been filled.
Photo: Matt Arthur, KA0PQW, (right) rides the bucket lift during an antenna project.
Congratulations and a big thank you to Handiham volunteer Matt Arthur, KA0PQW, for accepting this position. Our Net Advisory Group and Club President Ken, KB3LLA, agree that Matt will do a good job because he understands the technical workings of the nets, repeater, links, and nodes and has many years of experience that includes a wide variety of on the air operations, emergency operations, nets, repeater ownership, and volunteer work as an instructor at Handiham Radio Camps.
Matt is committed to working with our net control volunteers to keep the nets on the air, maintaining good technical standards and keeping them a place where we can check in and have fun talking with our friends. He likes the idea of net controls being able to shape their net sessions and finding their own ways of keeping the Handiham nets a welcoming experience for all who want to join us for the hour. This will continue our openness to a mostly informal and friendly net, but one with high standards that shows the Handiham Radio Club in a good light. It also keeps the door open for us to quickly respond to an emergency, should the frequency be needed.
Thank you, Matt for stepping up to the plate!
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