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Thread: Base station "parts"

  1. #1

    Default Base station "parts"

    Hello!
    I am super new to the ham world. Although I've already read up on a lot of things, I know I still have a lot to understand, aside for there obviously being a lot of information to learn, also because some of it is really hard to find!

    I'm asking this because while handheld transceivers are super easy to use, as you only need one piece of equipment to get it running, the same doesn't apply to base or mobile stations, that need more components to work. But something I can't find anywhere is, what are those?

    I know that besides the transciever itself, you need a power supply (..most times? Huh?) and an antenna... And coaxial cable... That is for connecting the antenna to the radio, right?
    Is there anything else that's strictly needed? What are all of those accessories that are also around? If they're not strictly necessary, what do they add?

    Thank you to anyone who points me in the right direction ^^

  2. #2

    Join Date
    Nov 2019
    Location
    Ash Fork, Arizona
    Posts
    88

    Default

    The handheld transceiver is easy to figure out. The manufacturers have put all the pieces together. There is still a "power supply" (battery). There is still an "antenna" (the rubber ducky on top. And in between the two is the transceiver or just radio. You can't see it but there is probably a small length of coax running from the transceiver to the antenna. But sometimes the antenna connection is right off of the circuit board.

    So base and mobile stations are not really different, they are just bigger. For a mobile station, say in your car, the "power supply" is the car's battery. Because you want to get the antenna out in the open, coaxial cable is needed to connect to the radio. Plus, the microphone is separate and usually attached via a connector on the front panel. You might even opt for an external speaker. Yet another piece of equipment

    The same radio could be used in a base or mobile station. In a car, the battery supplies the voltage and current. But as a base station, you need something to convert your household AC power to Low Voltage DC Power. To select the right power supply, you need to check your radios specifications.

    I have a Kenwood TM-V7A - Dual Band (2M/70CM) FM Transceiver. It's a little old and beat up, but it can be used in a vehicle or on your desk. It outputs 50 Watts (VHF) and 35 Watts (UHF). That's a bit more than your handheld radio would have. So to power it, you need a supply that can provide 13.8 V DC +/-15% and 11.0 Amps. This can be handled in a vehicle by the battery, but for your desk you would need a power supply that
    provides this voltage and current, as a minimum. Of course, the antenna is outside on a 35 foot tower so I can hit all the repeaters in a 50-100 mile radius.

    And, of course, as the radio's output power increases, so does the power supply current requirements. My IC-735 HF Transceiver can output 200 Watts. So to power it I use a ICOM PS-15 which can supply the 20 Amps required. The IC-735, and it's power supply, are pretty old (>30 years), so don't go looking for them on line.

    Overall, there is a lot to learn about radios. What doesn't help is that new technology continues to be available. So no only are you seeing new equipment but there are more operating modes available to the user. When I first obtained my license (1965), there wasn't much choice of modes. I worked CW on the low bands and AM on 2 Meters. But today, there are probably a dozen digital modes alone. So just take things a piece at a time. You can't learn everything at once. There are books from the ARRL or RSGB that can provide you with a good basis for understanding. I bought the "Understanding Basic Electronics" book for my son recently. But they have other books that go into detail about setting up your own station.

    If you don't understand something, just ask. There a lots of hams waiting to respond.

    Good Luck
    Martin, K7MEM
    http://www.k7mem.com
    Ash Fork, AZ - 60 miles from the Grand Canyon on Rt-66. Elevation 5,300 ft.

  3. #3

    Default

    Thank you, that is very, very helpful! (:

    I have two questions in my mind now...
    One of them is about connecting a base power supply (one that converts from powerline AC to the right volts and amps and DC) to a transciever. When you get those two things, can you easily connect them with the cables that come with them? Do you need to get any sort of cables or anything extra?

    My other question is about antenna tuners, as they seem to be very expensive... What are they for? When would I need one?

    Thanks again for shedding some light on things, as well as to whomever helps me further (:

  4. #4

    Join Date
    Nov 2019
    Location
    Ash Fork, Arizona
    Posts
    88

    Default

    Quote Originally Posted by TonyCole View Post
    I have two questions in my mind now...
    One of them is about connecting a base power supply (one that converts from powerline AC to the right volts and amps and DC) to a transciever. When you get those two things, can you easily connect them with the cables that come with them? Do you need to get any sort of cables or anything extra?
    It is usually pretty easy to connect from the power supply to the radio. All or most radios that you buy new include a power cable. Generally, the RED wire is Positive (+) and the Black wire is Negative (-). On one end of the cable, there is a plug that attaches to the rear of the radio. The other end usually doesn't have a connector because, there is no telling what power supply you are going to use. Sometimes, if you order the radio and power supply together, you can get the cable terminated on both ends, for a quick and easy installation.

    An example might be my IC-735/IC-PS15 combination. The power cable exits the rear of the power supply and terminates into a 6 pin Molex connector. This connector plugs directly into the radio. Quick and easy. An added feature of this is that, even though the power supply has it's own power switch, the power supply can be controlled (On/Off) directly from the radio. This allow you to stash the power supply out of the way so it doesn't take up desk space.

    Note that there are two types of power supplies. Analog and Switching. Analog power supplies use power transformer and circuitry to generate the DC Voltage/current required. With higher current power supplies the transformers tend to be very heavy an bulky. This means that, when shipped, they cost a lot of money. Switching power supplies do not use standard power transformers and can offer a higher current capacity than a Analog power supply, at a much lower weight.

    This sound great except that switching power supplies tend to generate wide band noise. It is common for many home appliances (washing machines, etc..) to have switching power supplies. This can lead to a frantic search for interference sources. But, until you get a radio on the air, don't worry too much about this. And there are high powered switching power supplies that don't generate wide band noise. An example would be the MFJ-4245MV. A friend of mine uses one of those power supplies with FT-991A transceiver. It works greate.

    Quote Originally Posted by TonyCole View Post
    My other question is about antenna tuners, as they seem to be very expensive... What are they for? When would I need one?
    This may sound like a simple question but its not. And it is very difficult to explain.

    Some say "antenna tuner" is a poor name, because it doesn't really tune your antenna. But that is an argument for another day.

    The transmitter section of transceivers, made for Amateur Radio use, are designed to work into a 50 Ohm load impedance. So your antenna system, which consists of your coaxial cable and the antenna, needs to also exhibit a 50 Ohm load. If this is true, then you don't need an antenna tuner. But no setup is truly perfect.

    A handheld radio takes care of antenna matching inside the radio. But, when you move an antenna away, there are many things that affect the antenna's feed impedance. Say you are erecting a dipole. There are many things that affect the feed impedance. Things like height above ground, length, wire size, nearby objects, etc.. So the dipole you erect may not exhibit 50 Ohms at it feed point. In fact, it is highly unlikely. The antenna may have a good feed impedance at the low end of the band, but the mismatch gets bad at the high end. This is where an "antenna tuner" comes into play. The may

    An "antenna tuner" usually goes between the radio and the antenna system input. The "antenna tuner"is adjusted so that your transceiver can see a good 50 Ohm load, no matter what the antenna system actually is. This is good since most new transceivers will automatically reduce output power, if the radio does not see a good match.

    The match, or mismatch, between your radio and antenna system is expressed as SWR (Standing Wave Ratio). The ideal SWR is "1:1". That means your radio is seeing a perfect match. But, again, this is not common. Usually, a radio can handle a 2:1 SWR before it starts to reduce output power. So, say you have a antenna system that exhibits 50 Ohms at the low end of a band, but 100 Ohms at the high end. If your operating at the low end, you adjust the "antenna tuner" for a good match, and you are set. When you move to the high end, you again adjust the "antenna tuner" for a good match, and you are set.

    There are manual "antenna tuners" and automatic "antenna tuners". The automatic antenna tuners are usually more expensive the the manual type. However, many of the high end transceivers come with automatic antenna tuners built in. With a automatic antenna tuner, you just push a button and it takes care of everything. But with a manual antenna tuner, you have to twist a few knobs. When you are knob twisting, you are actually solving a rather complicated equation that matches the transceiver to the antenna system.

    I am going to stop here, because there is way too much to write about antenna and antenna systems. Your best bet is to get a good book. The ARRL publishes a "Antenna Handbook" that does a very good job of explaining most things about antennas. And, of course, there is the "Amateur Radio Handbook", also published by the ARRL. Most hams keep a copy of both readily available. While they are expensive, it is easy to find older versions at ham fests. The content doesn't change much, from year the year, so old copies are very useful.

    I hop you can make sense of what I wrote.
    Martin, K7MEM
    http://www.k7mem.com
    Ash Fork, AZ - 60 miles from the Grand Canyon on Rt-66. Elevation 5,300 ft.

  5. #5

    Default

    Again, very, very helpful, thank you very much!
    So from what I understand, you can get up and running with an antenna, coax, a transceiver with a tuner, and a power supply, yes?
    I'll indeed try to get a hold of those books...
    Thank you for all the info and the recommendation!

    I also have a couple of questions about antennas, but I'll create a new thread for them in the right section. Thank you!

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