DIY Engineering @DIYEngineering
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DIY Engineering @DIYEngineering
In this section, one question was dropped and another about Keplerian elements was added…Dan
As a Technician Class licensee, you can make contacts via amateur radio satellites. Any amateur whose license privileges allow them to transmit on the satellite uplink frequency may be the control operator of a station communicating through an amateur satellite or space station. (T8B01)
Amateur satellites are basically repeaters in space. As such they have an uplink frequency, which is the frequency on which you transmit and the satellite receives, and a downlink frequency, on which the satellite transmits and you receive. As with other transmissions, the minimum amount of power needed to complete the contact should be used on the uplink frequency of an amateur satellite or space station. (T8B02)
Often, the uplink frequency and downlink frequency are in different amateur bands. For example, when a satellite is operating in “mode U/V,” the satellite uplink is in the 70 cm band and the downlink is in the 2 meter band. (T8B08)
The International Space Station often has amateur radio operators on board. Any amateur holding a Technician or higher class license may make contact with an amateur station on the International Space Station using 2 meter and 70 cm band amateur radio frequencies. (T8B04) Like most amateur satellites, the Space Station is in low earth orbit. When used to describe an amateur satellite, the initials LEO means that the satellite is in a Low Earth Orbit. (T8B10)
Amateur satellites are often equipped with beacons. A satellite beacon is a transmission from a space station that contains information about a satellite. (T8B05) FM Packet is a commonly used method of sending signals to and from a digital satellite. (T8B11)
How do you know when you are able to communicate via an amateur satellite? A satellite tracking program can be used to determine the time period during which an amateur satellite or space station can be accessed. (T8B03) The Keplerian elements are inputs to a satellite tracking program. (T8B06)
Two problems that you must deal with when communicating via satellite is Doppler shift and spin fading. Doppler shift is an observed change in signal frequency caused by relative motion between the satellite and the earth station. (T8B07) Rotation of the satellite and its antennas causes “spin fading” of satellite signals. (T8B09)
There were two question changes in this section. Question T4A02 was changed from a question about headphones to a question about using computers in the shack. Question T4A05 was changed from a question about band-reject filters to one about using an SWR meter. I’ve added that question to the appropriate section…Dan
When setting up an amateur radio station, choosing the radio itself is the most important consideration, but you must also choose a wide range of accessories, such as power supplies and microphones. In addition, how you set up the station is important for it to operate efficiently.
One accessory that you’ll definitely need is a power supply to provide the DC voltage and current that your radio needs. A good reason to use a regulated power supply for communications equipment is that it prevents voltage fluctuations from reaching sensitive circuits. (T4A03) When choosing a supply, check the voltage and current ratings of the supply and be sure to choose one capable of supplying a high enough voltage and enough current to power your radio.
If you are going to operate with one of the voice modes, you’ll need a microphone. When considering the microphone connectors on amateur transceivers, note that some connectors include push-to-talk and voltages for powering the microphone. (T4A01)
A computer has become a very common accessory in an amateur radio “shack.” All of these choices are correct when talking about how a computer be used as part of an amateur radio station (T4A02):
- For logging contacts and contact information
- For sending and/or receiving CW
- generating and decoding digital signals
If you plan to operate packet radio, you will need a computer and a terminal controller, or TNC, in addition to the radio. A terminal node controller would be connected between a transceiver and computer in a packet radio station. (T4A06) The TNC converts the ones and zeroes sent by the computer into tones sent over the air.
A more modern way to operate digital modes, such as RTTY or PSK-31, is to use a computer equipped with a sound card. When conducting digital communications using a computer, the sound card provides audio to the microphone input and converts received audio to digital form. (T4A07) The sound card may be connected directly to the radio, but it’s usually better to connect it through a device that isolates the radio from the computer. This prevents ground loops from causing the signal to be noisy.
Audio and power supply cables in a amateur radio station sometimes pick up stray RF. At minimum, this RF can cause the audio to be noisy. At worst, it can cause a radio or accessory to malfunction. To reduce RF current flowing on the shield of an audio cable (or in a power supply cable), you would use a ferrite choke. (T4A09)
Modern radio equipment is very well-designed, and harmonic radiation is rarely a problem these days. Even so, there may be times when it does become a problem, and you’ll have to take steps to attenuate the harmonics. To reduce harmonic emissions, a filter must be installed between the transmitter and the antenna. (T4A04)
Good grounding techniques can help you avoid interference problems. When grounding your equipment, you should connect the various pieces of equipment to a single point, keep leads short, and use a heavy conductor to connect to ground. Flat strap is the type of conductor that is best to use for RF grounding. (T4A08)
If you plan to install a radio in your car and operate mobile, you have a different set of challenges. One is connecting the radio to the car’s power system. Some amateurs connect their radio with a cigarette lighter plug, but this plug is not designed for high currents. Instead, a mobile transceiver’s power negative connection should be made at the battery or engine block ground strap. (T4A11) The positive connection can also be made at the battery or through an unused position of the vehicle’s fuse block.
Another challenge is noise generated by the car itself. One thing that could be happening if another operator reports a variable high-pitched whine on the audio from your mobile transmitter is that noise on the vehicle’s electrical system is being transmitted along with your speech audio. (T4A12)
The alternator is often the culprit. The alternator is the source of a high-pitched whine that varies with engine speed in a mobile transceiver’s receive audio. (T4A10) Should this be a problem, there are filters that you can install to mitigate the alternator whine. One thing that would reduce ignition interference to a receiver is to turn on the noise blanker. (T4B05)
Here are a few comments on my latest operations:
SKN. I worked SKN this year, making eight contacts overall. I used my Bunnel #9 key the whole time. I was going to pull out the J37 with leg clamp, but then remembered how much it hurt, so passed on it.
The eight contacts include a couple of Europeans on 10m: F6HLQ and IZ0CHC. I’m not sure that they were really working SKN, but I’m going to count them. F6HLQ was using a straight key for sure.
My first contact was K1PUB, a station whose callsign spells a word. This is not the first time that I’ve worked him, but it doesn’t look like I requested a QSL from him the previous two times.
New LOTW stats. Prompted by a Tweet by @jilly, who gave her LOTW stats, I decided to upload my QSOs. I hadn’t uploaded them since 11/18/13, and had nearly 300 to upload. The upload and QSL processing went very fast.
I now have 14, 234 QSOs records and 2,735 QSL records for a QSL percentage of 19.2%. My overall DXCC count is 132, with 130 on CW. The band that I’m closest to working 100 countries on is 30m, where I have 98 countries confirmed. I’m thinking that once I hit 100 on 30m, I’ll apply for the DXCC award.
10 meters. 10m has been in great shape lately. The band was in good shape for the 10m contest a couple of weeks ago, and yesterday morning it was gangbusters to Europe, too.
Later in the day, it was open to South America. I copied an LU calling CQ, but unfortunately he couldn’t hear me. A little later, I worked CX1JJ, a very good YL operator in Uruguay.
Lots of ham radio items in the news lately, so this post is longer than usual….Dan
Hong Kong’s ham radio enthusiasts lend a helping hand. More than just a hobby and a way to socialise, amateur radio provides vital communications to ensure the safe running of Hong Kong’s charity events.
Gwent radio hams ready to help in emergency. They are helping to guard the public in the event of a disaster, but you may not have even heard of them. Gwent’s RAYNET group – a bunch of licensed amateur radio enthusiasts who help the emergency services in the event of a communications meltdown – is part of a national organisation celebrating its 60th anniversary this year.
Lake amateur radio operator gets top marks. Lake County amateur radio operators, often called hams, brought home the bacon in a national Field Day event held earlier this year, it was announced Thursday.
Young hams make the grade. Surrounded by radio gear, Gene Clark sat in his chair and listened intently as his two sixth grade proteges were interviewed by a reporter recently. Dalton Duggers, 11, and Jordan Sirmans, 12, recently earned their radio technician’s licenses, making them two of the youngest licensed ham radio operators in Georgia. The two friends are are members of the Albany Amateur Radio Club (AARC) and are in the Gifted Program at Merry Acres Middle School.
Okanogan Amateur Radio Club recognizes first concrete pouring at Grand Coulee Dam. Dec. 6th, 1935, was the first “ceremonious pour” of concrete at Grand Coulee Dam. It was the first of a total of 12 million yards, which is enough to pour a sidewalk around the world at the equator twice. The Okanogan County Amateur Radio Club W7ORC sponsored a special event to celebrate the anniversary of the that pouring. Club members used their home radio stations, commonly referred to as “HAM SHACKS,” starting at 4 p.m. Dec 6, and ended at 4 p.m. Sunday, Dec 8.
Family saved by ham radio and Good Samaritan after car accident. On a cold, bitter night earlier this month, the actions of a Good Samaritan and a ham radio probably saved the lives of a family. It began at about 7 p.m. Dec. 6 when Cody Fowler and his wife, Tina, and their two sons, Jacob and Timmy, were on their way home from Pueblo. Because of the bitter cold temperatures and the icy roads, Cody turned around and drove back down the road, where he discovered that a red SUV had slid off into a ditch. The five people in the car had climbed back onto the road….