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The following accessories are covered: AC Adapters Antenna Multicoupler Antenna Splitter Antenna Switch Batteries Battery Chargers Cases Cassette Adapters DC Adapters Earphone Frequency Converters Frequency Counters Headphones Lightning Protectors Mobile Mounts Preamplifiers Preselectors Power Converters RF Adapters RF Filters Speakers Stands Surge Protectors Tape Recorders AC Adapters The purpose of the AC adapter is to convert your household AC voltage/current to DC voltage/current usable by your receiver. Some receivers come with an AC adapter since they are designed to run off of 12 volts DC (which allows them to be used in the home or a vehicle). A must have if you use your handheld at home. It can also be used to power a base or mobile unit with a DC power jack. The best one to buy is the "universal" type because they are so flexible. They typically allow multiple voltage settings, multiple plug sizes and positive/negative tip voltage (be sure to set this properly or you could have a bad day). Most radios with a DC jack have a small wiring diagram printed nearby. It usually consists of a dot surrounded by a semi-circle. The dot represents the tip of the adapter. Follow the line from the dot to the + or - symbol and you'll know what to set the tip polarity to! Be advised that some radios are not designed to use this form of external power if batteries are installed. READ THE OPERATING MANUAL BEFORE PROCEEDING! If your radio is capable of recharging the internal cells and you use alkalines, connecting up external power could lead to an explosive result! In some manufacturer's literature, you'll see references to a "mains charger" which should be taken to mean the AC adapter Antenna Multicoupler This device is designed to overcome the limitations of the typical antenna splitter. While being able to split an antenna signal into multiple paths to feed multiple receivers, it may also provide amplification to overcome the losses associated with such splitting as well as port isolation so receiver noise does not propagate to other attached receivers. Such devices are not cheap but really do pay for themselves over time. For a good brand, try Stridsberg Engineering who offers both 2-, 4- and 8-port versions as well as amplified and non-amplified models. Antenna Splitter When you have one antenna that you'd like to share among two or more receivers, you need some form of splitter which takes the incoming antenna signals and splits it up to be sent out to two or more receivers. Simple splitters will reduce the signal to each output based on the number of outputs. If an antenna input is split to two receivers, each receiver will only receive one half of the strength of the original signal. For a three-way split, one third. While the exact loss will vary depending on the physical characteristics of the attached receivers, just be aware that you will be loosing signal. That means that strong signals will be weakened and weak signals will be not be received at all! Such splitters also offer NO isolation between attached receivers. This means that noise from one receiver can work its way back up to the splitter and make its way back down to the others. To overcome this signal degradation and/or lack of isolation, a multicoupler can be used; just expect to pay for it. Antenna Switch If you have more than one antenna to use for your receiver, you can use a switch to select which one to use at any given time instead of having to manually unplug one and plug in another. Some switches allow for two or three inputs and the more expensive variety include a grounding position to be set when not in use. Be aware that inserting such a switch in your antenna path will add some loss, i.e. reduced signal strength; the price you pay for this convenience. Batteries These come in all shapes and sizes. With regard to handhelds, they usually take AA size cells of the alkaline, NiCd, NiMH, Lithium or Lithium-Ion variety Alkalines deliver a lot of power and are best known by the most common name brands (Duracell, Energizer and Panasonic) and have very long shelf lives Once semi-recent innovation are the rechargeable alkaline cells which need a special charger and have much shorter recharge cycles compared to other rechargeable technologies (NiCd and NiMH). NiCd (Nickel-Cadmium) are older technology rechargeable types. Most are rated around 700mAh but can go as high as 1100mAh these days. The have short shelf lives but most chargers are designed to handle this type. Properly cared for, they can be recharged 300 times or more. Improper care can reduce this to 100 or less. NiCds are effected by voltage depression phenomenon which happens when they are not fully discharged and rechared on a regular basis. NiCds are also toxic to the environment. NiMH (Nickel-Metal-Hydride) are newer technology rechargeable types. Most are rated around 1000mAh and go as high as 1500mAh these days. They have longer shelf lives and no voltage depression effect but are more costly, require a special charger and can only be recharged 200 or so times. No problems with environmental toxicity here. Lithium cells are one of the newest and most costly technologies. They have exteremely long shelf lives, are very expensive but deliever more power than alkalines. They are also extraordinarily light. Lithium-Ion batteries are widely used in notebook computers for their high energy storage potential. But they are also EXTREMELY expensive. I know of only one radio which has such a battery and it is a amateur transceiver (Yaseu VX-1R). I do not know what their benefits and drawbacks are when it comes to recharge cycles, shelf life and charging considerations. Another source of power which can come in handy are the sealed lead acid and gel-cell batteries. Many are rated at 12 volts and can power a 1 or 2 Amp device for several hours. They are usually left plugged to an AC adapter to charge from household AC current. They can then be unplugged and used during power outages or in places where AC/DC power is not accessible. Just think of them as a large, external, rechargeable battery. And it will be your job to purchase or construct an adapter to convert the power receptable format (usually a car cigarrette socket type) so that it can be plugged into your radio's external power DC jack. Battery Chargers Designed to charge rechargeable batteries, they come in a billion different sizes and configurations. Most are designed to recharge NiCd cells. The basic difference is the number and type of cells that can be accomodated as well as the charging current used. Keep in mind that the charging current is of greatest concern. Cells are usually designed to be recharged at only one or two rates (typically a slow charge/low current or a fast charge/high current). If the current is too large, it will generate excessive heat which will damage the cell contents thereby shortening its lifetime. Most of the cheaper chargers have either a constant charging period which is only good for the cell when it nearly exhausted. Some chargers have no timer at all; they continually charged and it's up to you to determine when the cell(s) should be removed. When thinking of NiMH cells, it's VERY important to use the proper charger. A NiCd charger CAN'T be used as it will overcharge the cells. A good NiMH charger will have a voltage detector to monitor the progress and the better units have temperate sensors to make sure the cell's thermal limits are not exceeded. These features work on NiCd cells just as well. Other handy features to look for are "conditioning" and trickle charging. Conditioning is used to discharge the cell(s) before they are recharged thus helping to prevent the dreaded memory effect (voltage depression). Trickle charging simply supplies a very small current to the cell after it is done charging to help insure its charge does not degrade; you can leave the cells in for long periods of time without worrying about overcharging and the cells are fully charged when you need them. Expect to pay more for such chargers but when you compare it to the investment made in the batteries themselves, it easily pays for itself quickly; especially if you have several sets of such cells. Special alkalines available these days can be recharged but only by using the supplied/recommend charger which use very small currents and/or special charging techniques. Do not try to use a NiCd or NiMH charge on these; to do so is just asking for a disaster! As usual, Radio Shack carries a large line of chargers. You might also check with amateur radio dealers for the Maha line of products. Cases Designed to protect a handheld from abuse encountered during its travels. Older manufacturer cases were made of hard, thick leather designed for maximum protection but an eye-sore. Newer designs are made of softer, thinner leather and usually fits like a glove over the various contours. Most newer OEM cases are made of cordura If you travel with your handheld a lot, a case can protect your investment and assure a longer life if not a higher resale value. Be aware that some cases force the belt clip to be removed in order to be used. Some allow the stock clip to be uses as is. Others have a belt loop which is not as flexible but is more secure Take into consideration whether or not you can use the radio while it's in the case. Can you see the display? Can you use the keypad? How good does the audio sound? Can you get to the power jack without removing? Not all cases are created equal! Cassette Adapters Originally designed to allow CD players to be played through your car's tape cassette player, this device is an essential part of the mobile monitor's arsenal. It consists of a cassette attached to a cord terminated in a 1/8" stereo plug. The plug is inserted in the scanner's hearphone/earphone jack to transmit the audio to the head contained within the cassette which in turns transfers it to the radio head. You'll also want to buy a mono to stereo adapter so that the scanner audio gets fed to both stereo channels When not in use, be sure to eject the cassette to avoid flat-spotting the heads which occurs slowly over time. While it probably won't be noticed for scanner audio, it will be when you go to play a high fidelity cassette. The biggest drawback is that you won't be able to use your car radio for AM/FM or casette use. So think about getting an external speaker; possible an amplified version if your vehicle is noisy DC Adapters DC adapters are used to supply power to your radio while used in a vehicle of some sort; usually your car/truck/boat. Of course the radio in question must have been built with a DC jack or you have to have the skills necessary to add one. Most base/mobile units are designed to accept the vehicle voltage which is usually in the 12 - 14 volt range. Handhelds usually range from 3 - 9 volts so some form of voltage division is needed to reduce the vehicle supply accordingly. Base/mobile units usually need about 500 milliamps or more of current while handhelds operate in the 200 - 400 range. Be sure the adapter you pick can source the current drain your radio will need. Many radio dealers sell universal adapters which are VERY handy. Not only do they have a switch which allows the output voltage to be selected, they come with an assortment of plugs to fit most radio DC jacks. These plugs can usually be inserted in two ways allowing the tip polarity to be selected as negative or positive (be sure to use the proper polarity or your radio could become a hi-tech paperweight). Most units have a fuse built into the adapter plug to prevent excessive current flow that could damage your car and/or radio. Some even come with a spare fuse to replace on the fly. Be sure you investigate any problem before simply plugging in a new one. And its always good to carry spares. Just be sure to use ones with the same rating as recommended by the manufacturer. Earphone Some receivers come with an earphone for private listening. Some are better designs contoured to fit the ear which helps with comfort during extended listening sessions. You should also consider cord length, color and whether or not an ear clip is necessary. While great for private listening, they allow the other ear to hear what's going on around you which is important in some cases where headphones might be a hindrance or danger. Earphones are also great for unobtrusive monitoring. Put the radio in a jacket pocket and feed the cord up your back. From there it's a short jump to your ear making it very hard to detect what you're doing. Frequency Converters These aren't found for the most part nowadays. Their basic purpose was to shift a frequency range from one part of the spectrum to another. Most were used to allow frequencies in the 800-900MHz range to be received on a radio in the 400-500MHz range, thus they were referred to as "down-converters". When the 800MHz public saftey band was in its infancy, such converters were used to allow people with older radios (which did cover 400-500 but not 800-900) to listen in on this new frequency range. As a side effect, such devices gained popularity since they allowed reception of cellular frequencies on newer radios with had these frequency ranges blocked. The federal legislation passed in April '94 which banned the manufacture/sale/importation of cellular-capable radios took these converters with them. Frequency Counters Basically a wide-range receiver designed to sweep its entire spectrum coverage (usually a few Mhz to 1GHz or so) in a VERY short period of time (usually 1 second). It then displays the frequency of the strongest signal it found during its sweep. Such devices are useful for finding the frequency used by an agency which is not known or published. Spend enough money and you can get counters which have memories for storing "hits", decoding CTCSS/DCS data, displaying trunked radio ids, interface with GPS units, and on and on. Don't think that these are the cure-all that they appear to be. Counters are pretty dumb...they only tell you the strongest signal in your vicinity...which is usually a pager, FM radio or TV station signal. Not quite what you intended. To use a counter effectively takes patience and practice along with the use of a properly tuned antenna and perhaps some filters to help block out nasty signals you care nothing about. Be sure to steer clear of those counters designed for lab work. Get one designed for radio entusiasts/technicians which would probably come from Aceco, Optoelectronics or Startek. One very useful feature of some Optoelectronics counters is the ReactionTune feature which, when connected to a supported radio, will tune it to the displayed frequency thus allowing the transmission audio to be monitored on the radio. The new Aceco models seem to provide this same capability! See my New Scanner Users FAQ for some more frequency counter details. Headphones Since receiver audio, for the most part, is limited to voice transmissions, you'll be more worried about weight and comfort than fidelity. Headphones are usually designed for stereo applications (separate channels for left and right) while most scanners output monaural sound (one channel). But there are also monaural headphones and stereo scanners. So be sure to read up on what you have and what you'll need. In most cases, you'll simply plug an adapter into a monaural scanner to feed its audio to both left and right channels so that you can use stereo headphones. Some headphones come with an in-line attenuator allowing the volume to be controlled there instead of having to adjust the radio volume itself. Headphones are not only good for private listening but for helping to pick out weak signals; especially on HF. Lightning Protectors The SAFEST form of protection from lightning is to detach the antenna co-ax and move it a FEW FEET AWAY, and unplug the radio's AC power cord. For limited protection, many companinies now offer supressor equipment to protect antenna lines as well as surges on the AC power supply. You'll find most products will advertise that they do not warrant against direct lightning strikes; only excessive surges created by nearby disturbances. The best devices usually need a separate connection to a good ground connection to shunt the excessive voltage harmlessly away. So be aware of this when comparing and know you might need to do some minor electrical work (or pay someone to do it for you). Some devices are active (requiring power) while others are passive and simply insert inline (co-ax or AC power). Therefore, prices can range from $30 to $200. It's also a good idea to protect other equipment in your home like stereos, VCRs and TVs. Co-ax TV cable can be a nasty way for forces outside your home to make their way inside. My Sony TV had to make a trip to the service center because of a local discharge carried to it thanks to the cable company. It, and all of my equipment, is now much better protected. Good places to start looking are the Radio-Ware, MFJ and Universal Radio web sites. Mobile Mounts These are used to hang your handheld receiver while traveling in your car, truck, etc. The original approach was to attach one piece of velcro to the dash (or wherever you want to "hang" your radio) and another piece was attached to the back of the radio. There are units today which use screws or some form of "stickum" to mount the hanger in place. Still others use a simple plastic hanger which slides down between window and door frame. With the growing use of cell-phones, many companies are making various devices to hold onto them in the car. Some mount into place with screws while others use suction cups to attach to glass. Either way, most of them will easily accomodate handheld receivers. I personally use the Scanmaster QS200. It is quite small and has springy metal fingers which grip onto the plastic slats of most heating/cooling vents. Since the backside of the unit rests against these slats, their angle determines the angle of the radio once attached (important for reading the display easily), which is done by simply sliding the belt clip over the front plate. This plate has a thick rubber pad to help prevent scratching the radio's rear panel. I like this approach since it is unobtrusive, useful, easy and non-permanent. I think the only radio which I've note been able to use with this is the new Sony ICF-SC1 models since their belt clips are too wide. Here's a picture of my QS200 in action Pre-amplifiers Most radios come with circuitry in the very front-end which is used to amplify the strength of incoming signals soon after they are led off the antenna. To help amplify signals to an even greater degree, you can attach an external amplifier that strengthens signals even before the radio gets them...thus a "pre" amplifier While this seems all good and dandy, signals get amplified along ambient noise. That's just the cost of doing business. So you'll probably be rewarded with more and stronger signals, but also expect to get more noise, which might put a strain on your scanning and searching. What you have to be really careful of is the design of the unit itself as well as where it's used in regards to local strong signals. If strong signals are amplified even further and/or the unit is not well designed, this amplification process can generate LOTS of nasty intermodulation interference. So a well designed unit is going to cost a pretty penny. And there might be locales or frequency ranges where it's just too much of a hassle to use. Consider yourself warned! When comparing units, be careful to note their frequency limits. Some are made for HF while others are for VHF/UHF. Even among "like" units, coverage can vary. Is the unit's amplificiation (gain) set or can it be varied? Some units can attenuate (weaken) signals as well Some need an external power supply while other use batteries. Some can be used both ways! When turned off, does it allow signals to pass through uneffected? Some of the more costly units come with built-in filters to help you get around signals you'd like to avoid amplifying since doing so could create intermod. GRE makes two VHF/UHF units (base and handheld) which are marketed under their own name as well as rebadged for sale at Radio Shack. Grove carries the PRE-5A for VHF/UHF. MFJ carries two or three units for HF work. Scanmaster over in the UK makes two models. Preselectors Basically designed for HF use, it typically consists of a set of selectable filters for various frequency bands. By only letting through a narrower set of signals, the receiver is not inundated with undesired signals which might produce images, intermodulation or desensitization. Some units come with amplifiers and/or attenuators to help further condition signals so that you can listen to practically any signal you desire with just the right clarity. Power Converters These devices are used to convert your automotive DC current into AC so that you can use normal household equipment, like TVs, VCRs, etc. in your car, truck, RV, etc. They usually come in different power ratings so be sure that the device will be able to supply the current your equipment will need. Most receivers these days come with some form of DC jack so that you can use a regular DC adapter. If all it has is a regular AC cord, you'll have to use a power converter. Pay careful attention to be sure and shut off the device and/or converter when not in use or you might wind up with a dead car/truck/RV battery. RF Adapters You can never have too many of these! They're used to convert between the various factors used for RF cables and antennas. While most receivers use the BNC format, most base antennas use PL-259/SO-239. Older receivers may use the Motorola F format while newer designs are starting to see mini-UHF, N, TNC and SMA. Co-axial cables use F-type, BNC or PL-259. At any one time you may need to connect any radio to any cable to any antenna so you'll need to be able to convert one format to another. And since connections come in both plug and jack (or male and female) varieties, you'll need to account for this as well. By having a large assortment on hand, you'll be able to do the job in the minimum number of connections. Remember, the more adapters you use, the more your signal gets lost/weakened. RF Filters Filters are designed to let only a restricted range of signals through. Any others are severly attenuated (weakened) to keep them from entering the receiver. This is usually done to reduce chances of interference due to images or intermodulation. They can also be used at times to help allow preamplifiers to use more gain. Low pass filters are used to allow only lower frequency signals to be let through. So a 50MHz low pass filter would allow through all signals below 50MHz, but block anything above 50MHz. High pass filters do just the opposite. They allow high frequency signals to pass through but block lower ones. Band pass filters are used to pass a specified range of signals. They'll block all frequencies below a designed frequency as well as those frequencies above another designed frequency. So a 50 - 200MHz band pass filter would allow all signals between 50 and 200 MHz to pass but block all signals below 50MHz and all signals above 200MHz. Band rejection filters are the complement to band pass filters. Instead of letting a band of frequencies through, they block them and allow all others. Such filters are usually designed to block small regions of the frequency spectrum where strong signals are often present and thus present the chance for interference. Common band rejection filters are made to block the CB, TV, FM and civil aeronautical frequency ranges. There are newer filters today that are designed to block VERY narrow ranges belonging to the stronger and most popular pager signals. Keep in mind that several filters can be used and "stacked" to custom-modify the signals being received. Just be aware that doing so will probably attenuate (weaken) the signals that are let through due to all the component connections. Filters are great for receivers but don't overlook the useful role they can play for effective use of a frequency counter! Speakers External speakers come in handy for a number of reasons. There might be a need to supply the audio a long distance from the receiver position. Such units generally offer better fidelity than the one inside the radio. At a minimum, such a selection allows you to pick the type of audio response you find most pleasing and easy to listen to. Which is of importance for extended listening sessions. In the mobile enviroment, such a speaker can place the audio closer to ear thus helping to overcome background noise. There are also amplified speakers which can help in any environment to make sure the receiver audio is heard. While most external speakers and scanner audio jacks are rated at 8 ohms, be sure to check both since 32 and 64 ohm variations do exist. Stands Stands are used to "prop up" your handheld so that it can be used as a base model while preventing it from tipping over. Some models are simple plastic enclsosures designed to keep your radio upright at all times but they don't allow much use since most of all of the keypad is blocked. Better models have a simple metal post to which the radio attached via its belt clip. Not only does it all full use of the keypad and controls, some have adjustable settings so the radio can be tilted at the proper angle for reading and best contrast viewing. Fancy units come with a built-in AC adapter to supply power to the radio to save on batteries. Just be sure to check into the plug size and voltage requirements. Some units have a BNC antenna jack for strain relief. You typically plug your antenna co-ax into the rear and a short jumper then connects to the radio itself. While some signal will be lost, this more than offsets the gain from relieving the pressure put on the radio's BNC jack due to the heavier antenna co-ax weight. I personally use a Scanmaster QS300 which is all metal with a felt base. It allows the post to be angled for convenience and uses an antenna adapter strain relief. High quality and high cost. Here's pictures of my QS300 stand-alone and supporting an AR8200 Surge Protectors Anyone familiar with computer and office equipment will tell you how important surge protectors are. Random spikes of energy in the power lines (caused by your power company working on the lines or repairing damage) can mean nasty results to your AC power supply that feeds your radio equipment as well! Good protectors are designed to filter the input to help maintain a semi-constant voltage and current supply while filtering out nasty power spikes that can be many thousands of volts! Not all surge protectors are created equally either! Don't expect the $10 variety to match the protection of the $30 models. Read all the packages carefully as well as the fine print, and note the differences between them. Some models come with notification lights or alarm buzzers to alert you to a warning condition. Be sure to pick a model that will suit your needs and operating environment. And follow the guidelines given with the device purchased! Certain conditions can render the device's protection nearly worthless so heed all warnings and cautions! If you find your equipment can't power up one day, check to see if the protector has been "tripped" due to a spike. Try resetting the device's circuit breaker and you should be back in business. Tape Recorders Hooked up to your radio, a tape recorder can be used to log traffic while you're away or to record your favorite transmissions The VOX types don't work very well in most instances. These are designed to remain paused but being recording as soon as audio is detected on the input line. Problem is that most radios have such poor/noisy signals that even when the frequency transmission goes away, the VOX unit doesn't turn off due to this noise "hiss". So the tape recorder starts recording and never turns off. Not what you want. A better option would be to use a radio that not only has an audio output line but a tape record control line as well. The audio is plugged into the recorder's microphone input while the control line is fed into the remote socket. The radio then tells the recorder when to start and stop recording with the control line. So when a signal is detected, the radio tells the recorder to start and when the signal goes away, it tells the recorder to stop. With computers becoming more popular in the home, many hobbyists are using audio software to record audio fed into the computer soundcard as files on the hard disk. The output of the radio is fed into the soundcard line-in or microphone jack. The control software can usually set the audio activation level allowing you to set this threshold just above any noise "hiss". I use this approach and RecAll software to monitor all day long while I'm away. Each transmission is time and date stamped so that I can easily match it up with any radio control software log files which then tells me the frequency the traffic occurred on. I can easily listen to any transmission and as many times as I like all with a few clicks of the mouse. I don't know how I lived without this! This integration between radio control software and soundcard recording software is becoming more popular as more and more third party radio control software vendors are including this feature with their products to make life even easier! Accessory Dealers Amateur Electronic Supply (AES) Audio Implements C. Crane Company Com-West Radio Systems Limited Copper Electronics Inc. CQ Direct Durham Radio Sales DX Communications Grove Enterprises Ham Radio Outlet (HRO) the Ham Station Javiation Knights Lentini Communications, Inc. MAHA MetroWest, Inc. MJF Enterprises, Inc. Nevada Optoelectronics Radio Shack Radio-Ware The RF Connection Scanner Master Corp. Scanner World, USA Scanners Unlimited SSB Electronic Stridsberg Engineering Tech America TELCOM GmbH TEXPRO Universal Radio, Inc. Waters & Stanton

Copyright © 2002 by Richard J. Wells