(2012-01-26) HAM-holiday

HAM-radio is a hobby that can last a lifetime. When I got my license last year, I started out as most newbies do and was content just to talk with nearby amateurs on the 2M and 70CM bands. Those bands are good for the rookie as they require very little in the way of antennas and setup. I frequently used the local repeaters as well. From there most new hams eventually find new bands and modes to explore. Pretty soon I set my eyes on the shortwave bands.



On shortwave you can speak to your own country, nearby countries and if the conditions allow: the whole world. The trick is that shortwaves frequencies allows for something called skip. This phenomenon is not just something you find on the shortwave, but shortwave is where most of the interesting HAM-radio traffic is going on, so its the natural place to hang around. I wont get to technical here, but skip is what makes broadcast beyond the horizon possible. Now, the pesky ball we all live on is round, and this puts a limit on how far a radio-transmission may reach before disappearing into the blue yonder. But then there is skip. Some atmospheric layers (known as D, E and F-layers) cause radio waves on some frequencies to bounce rather than just disappear into space. To simplify it: Assume that I live in country A and country B is adjacent to country A. Country C is far on another continent and theres no way for my transmissions to reach there, because of the horizon-problem. But the transmissions may actually bounce off of the atmospheric layers and skip country B, landing in country C. Unless my antenna position and transmission power allows for it, no one can hear me in country B, but I can be heard in country C. And heres why shooting skip is so popular: theres no easy way to know exactly how well it works or who that may listen. The skip conditions can be monitored thanks to online weather services, but exactly how well it works out at a given moment, you will have to find out by experimenting. Theres something Forest Gump of the whole situation. You never know what you get out of the radio box when you tune in.

This I know: shortwave reception is troublesome in big cities. I live in Stockholm in Sweden and northern Europe is not a bad place to be for a HAM-operator, but the city poses two big challenges for me: RF pollution and antenna placement. RF-pollution can be, but is not limited to: my neighbors plasma TV, the nearby underground station, computers, poorly built power supplies and even the ventilation system in the building across the street. Its bad, but can be handled. The worse problem in my case is the fact that I live in a flat. I cant setup 40 meters of long wire because I dont have a yard. Now, there are ways around this as well, but the situation is not as good as one could hope for. However, my family owns a house in the country. A few weeks ago, I packed my HAM-stuff and spent my vacation in northern Sweden, and thats the story youre about to hear.

The preparations

The first semi-portable rig I assembled was battery powered and mounted inside a sturdy backpack. It worked well, but was too cumbersome to carry around. I figured that I would probably spend my time inside of or near a building, so I simplified the setup a bit. The antennas I use are two homemade random wires I created by cutting 25 meters of loudspeaker wire into discrete lengths. I created two antennas from the original cable. The first random wire has a radiator length of 20 meters and a ground cable of 12 meters. The second antenna has a radiator of 8 meters and a ground wire of 5 meters. I use the remaining 5 meters for my loudspeakers at home. The longer of the antennas is used for the 80 and 40 meter bands and the shorter one for is the 20 and 10 meter bands. Now, you cant just connect the antenna-wires to the radio and expect it to work. My HAM-radio comes with a rather standard unbalanced connector, which I have connected to an antenna-tuner. From the antenna tuner I have connected a 10 meter long feed cable that goes in a 4:1 balun. A balun, or balanced to unbalanced transformer, is the box that the loudspeaker -cables are attached to in one end and my feed cable is attached to in other end. The antenna tuner is used to tune the antenna. All normal HAM-radios are built to function with an antenna that has an impedance of 50 Ohms. The problem is that impedance is a function of the frequency youre transmitting on and the length of the antenna. To be perfectly resonant and thus present the radio with an impedance of 50 Ohms, the antenna length must match the frequency. This is a big oversimplification, I know, but basically thats what its about. Most antennas are compromises of some sort. If you want to broadcast on the 80 meters band, the perfect antenna should be a multiple of 80 meter. A half wavelength dipole for the 80 meter band should thus be 20 x 2 meters long. The calculations can be very complex for some types of antennas and even in this case, the calculation comes with a twist. The optimal length is (wave length / 2) * 0.96. I have no idea what the reason for removing 4% of the expected length is, but its said to be an optimal solution for most radios. My antennas are random wires and not strict dipoles. When I designed them, I didnt expect to be able to control the environment in which they would be used, so the random wire felt like a simpler and more flexible construction to me.

The radio itself is a Yaesu 857D. It covers all relevant shortwave bands, 2 meter and 70 cm and comes with all the modes you need and then some. The radio features fair filtering capabilities and comes with everything you expect to find in a shortwave radio. In short its a well-rounded performer that neither excels nor underperforms in any situation.

Going there

Now you know a little bit about the stuff that went into my backpack before I went away on vacation. The family house in the country is actually close to one of the more popular ski-resorts here in Sweden, but this time I wasnt there for the skiing. As I came up rather late and it was dark, I didnt feel like setting up the antenna. I just tossed the radiator and the ground wire on the ground to see if it worked. In spite of this poor setup, the reception on the 80 meter band was great. I didnt want to try to broadcast with the antenna still on the ground, so I spent the evening listening. As the light of day came back in the morning I installed the antenna between the house and a nearby tree. A dipole or random wire must be mounted at a height of at least of the wave length you intend to tune into. But I had no way of reaching 20 meters above ground with the equipment I had in possession. The antenna placement was therefore hardly optimal, but for my purposes it would do.

My intent was mainly to work on the 80 meter band. Spanning the frequencies 3,5 to 3.9 MHz, this band has some interesting skip-properties. On daybreak, the skip conditions deteriorate and confine transmissions to a local area. In my case, this meant Scandinavia and the northernmost parts of Germany. As soon as the sun sets, the rather silent band comes alive as Europe lights up like a Christmas tree. However, for me the day time was the time I was looking forward to. In the morning and until the sun begins to set, there are a lot of rag chewing going on. Raw chewing is a HAM-term for a general discussion as opposed to competitions or tests. Think of it as a predecessor of todays internet chat. Only theyre often more technical in nature.

Finally all was setup and tested and it was time to find one of those roundtables. At this time I want to remind you that HAM-radio generally is not full duplex. What I mean is that you can transmit or you can receive but not the same time. Youve probably seen or even used a walkie-talkie at some time. Remember how you have to push a button to speak and the release the button to listen to the reply? This button is called PTT or push to talk. The legal side of HAM-radio does not put that many technical restrictions on how you may use your radio. So theres nothing hindering you from use a setup that allows you to simultaneously listen and transmit. But the PTT is still the least common denominator and this means that conversations over the HAM-radio work a little bit different than over phone. In HAM-lingo a conversation is called a QSO and when more than two stations participate in a QSO, it becomes a roundtable". Generally the person who started the QSO also owns the frequency for the time being. They often rotate who is allowed to speak at a given moment, so that every participant waits until their call sign is called up. The systems works, but in the beginning it may feel a bit intimidating when your call comes up even when you have no idea what to say. If the QSO only have two participants, theres no need for any list, as the conversation just flows back and forward between them.

After a while you find out that many of the roundtables start at a preset time and many of the roundtables have had pretty much the same core participants for the last 20-30 years. The best way to learn is to tune in and listen. A good HAM keeps a log of his/her QSOs. My first QSO was at 07:30 on 3623 MHz as I checked in to the Nomira-roundtable. The first 5-10 minutes you could hear faint communication in Polish in the background, but as the sun rose the conditions changed so fast that they were gone and that just left the Nomira-roundtable on the frequency. Whereas my reception was good to great, I was quickly reminded of the suboptimal antenna-placement when I hit the PTT. Most of the participants could hear me, but the not all of them. At full power (100w) the signal reports I got back was ranged from fair to good from those that could hear me. I was still satisfied and continued to look for other QSOs after the Nomira-roundtable had concluded their daily rag chew. Nomira is a Christian HAM-radio organization and theyre very nice and helpful people and made me feel right at home on 80 meters. During the few days I was on vacation I participated in a number of roundtables and QSOs and also tuned into a few pirate radio-stations. Among them was a station claiming only to broadcast 2 hours per year, calling themselves Radio Mistletoe. This and many other interesting things is what make HAM-radio such a fascinating hobby. Should I ever get tired of rag chew, theres a plethora of other activities out there such as CW (Morse code of radio), RTTY/PSK32(data transfer), SSTV and contests.

The radio amateurs of the world have a long history of inventing new technologies, helping others in distress and generally breaking boundaries. Im proud to follow in my grandfathers footstep and while Im an agnostic atheist, the idea of him sitting on a cloud and listening in on his grandsons transmissions while muttering Humph!... Back in my time really amuses me.


Tags: HAM, HAM-radio
Posted: 2012-01-26 by Erik Zalitis
Changed: 2013-04-17 by Erik Zalitis

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