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Owatonna Steele County Amateur Radio 30-Apr-2010

Ask Elmer

Ask Elmer is a collection of questions asked by new licensees. Answers are provided by the OSCAR membership. These are general questions and the brief answers may not apply to all situations. Although we try to be accurate, the risk of implementing any information provided here is at the user's risk. Contact an OSCAR member for additional help.

Can I plug my radio into the wall as I listen to ragchew? Will it damage the battery?

Keeping the radio connected to the wall charger that comes with the radio for a long time is probably not a good idea. Some chargers are not well filtered and someone may notice a hum when you transmit, especially if the battery has a low charge. Also, many radios do not include a circuit to control the battery charge. Keeping the wall charger continuously on the radio may shorten the life of the battery. Some radios show the battery level when the radio first turns on. It would be a good idea to look at the battery charge level and become familiar with the voltages that appear when you have a fully charged battery and a nearly discharged battery.

What size power supply do I need for my radio?

Look in manual for the radio for the current consumption at the highest power output. With that information, select a power supply that will provide at leaset that much continuous current. Power supplies may have a specification for continuous current and peak current. For example, the ASTRON RS-35 has a rated peak current of 35 amps, but rated at 25 amps continuous duty. Most power supplies will output 13.4 volts, a voltage similar to the alternator output on your car.

If the manual is not available, then the maximum current can be estimated using Ohm's Law. You should note that transmitters usually operate with 50% efficiency. This means a 50-watt transmitter requires 100 watts of power. Remember one part of Ohms Law is Current = Power divided by Voltage ( I = P / I ). For a 50-watt transmitter, the power supply should be capable of supplying 7.5 amps (100 watts / 13.4 volts). It is always a good idea to add a couple of amps to this estimate to provide a level of safety as well as any accessory equipment you may add.

I just bought a new Yaseu radio and it beeps every time I press the transmit key. What's going on?

Newer Yaesu radios include a feature called WIRES, which is enabled by default from the factory. WIRES is a system similar to EchoLink®. Look up the WIRES feature in the manual that came with your radio. It will tell you how to disable this feature and eliminate the beep.

What frequencies should I program into my radio?

The OSCAR Home Page includes most of the repeaters in Steele County and the surrounding area. Depending on where you live, you should program the repeaters you think you may use. If you live in Owatonna, for example, the Owatonna and Meriden repeaters are a good start. Once you become familiar with those repeaters, then add some more. Don't forget to add the simplex calling frequenies: VHF (146.520) and UHF (446.000).

I want to get a mag mount for my handheld. The catalog talks about different types of connectors. What does SMA, PL-259, NMO, BNC, etc. all mean?

All radios will have a connector of some sort to make the connection between the radio and antenna. Even the rubber duck on a handheld radio could have different types of connectors. Most mobile radios have a "PL-259" connector, although "N" connectors are becoming more common. New handhelds tend to come equipped with "SMA"connectors, although they may have "BNC" style. When you select an antenna, be sure the coax connection matches your radio. If it does not, then you will have to purchase an adapter, which adds unnecessary expense and becomes more cumbersome. Check out the Amphenol RF Products web page for a description of the many many types of RF connectors, although you will routinely come across only a few of them.

On a related note, be aware the antennas and antenna mount may have different connections. This won't be a problem if you purchase a antenna and mount as a set. If you buy them separately, be sure the mount and antenna match.

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