Category Archives: Indoor Antenna

Got a bad antenna? How to figure it out.

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You spent a ton of money on a new scanner and another small fortune on a fancy outside antenna and feedline. Everything worked great until one day the scanner sent silent. Now what?

Here are some steps to try and figure out what happened. Did your target move to a new frequency or radio system? Did the antenna fail? The feedline? Maybe the radio itself isn’t working. Do this stuff and you can figure out where the problem lies.

First let’s do the easy stuff. Program in the local NOAA Weather station into the scanner. These transmit continuously on 162.400 thru 162.550 MHz. This makes them a great way to test your radio setup for proper reception. It is also an easy way to compare antennas and feedlines. If your radio picks up the weather transmitter then at least the system is working properly. Compare your outside antenna to the back-of-set antenna, the outside one should work better. If it doesn’t then there is probably a problem with it.

If you cannot hear your local weather station (and you know that you could before) then you need to figure out if the problem is with the feedline, the antenna or the connectors. First do a visual inspection of the connectors on the radio and coax and look for obvious problems. If you see nothing wrong then check the other and (at the antenna). If possible use an ohmmeter and check for continuity between the two ends of the coax and that the coax is not shorted. Disconnect the antenna from the coax since some antennas show a DC short when connected.

If you can hear the weather channel then the problem is probably not the antenna. It is more likely a programming issue or perhaps your agency has change radio systems. These days it is very common for many agencies to be converting over to large area-wide digital radio systems. It is often less expensive to do that than to replace older infrastructure. Some states have built statewide systems open to all local and county agencies to use. These states include NC, SC, MI, IN, OH, IL, MN, MO and others. Check your local area at the RadioReference.com database and see if there is a new channel or system listed there. Also check at the very bottom of the county page at RadioReference. If there are regional or statewide trunking systems listed check that system for your local agency.

If you find out that your local agency has moved to a new system then it is time for either reprogramming your current radio (if it will work on the new system) or replacing it with one that is compatible. We can help you pick the right radio for your area, just call one of our scanner experts. Don’t throw away the old radio, you can still use it for other things like aircraft, railroads or whatever old channels your agency retained after moving.

Got a bunch of scanners and only 1 antenna? Get a Multicoupler.

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Got radios (plural)? If you have more than 1 radio and want an outside antenna you can share the antenna with multiple radios. There are 2 ways to do this, the cheap way and the right way.

The cheap way is to just put a passive splitter or “T” adapter. While this will work for 2 radios listening to strong local signals, it will not work well for anything else. It also opens you up to interference between the two radios.

The right way is to use a multicoupler. A multicoupler has special circuitry to isolate the radios from each other so they don’t cause interference. It also reduces loss and maintains proper impedance matches. Active (powered) multicouplers include a small amplifier that overcomes the insertion loss caused by the multicoupler itself so that the signal appearing at the radio is the same as it would be if the antenna were connected directly to it.

The Stridsberg line of Active Multicouplers are well known as the best way to allow many radios to share a single antenna. With the isolation and amplification provided by it there is little or no interference between the scanners. You can connect up to 8 receivers to one antenna with no loss or interference.

Stridsberg multicouplers come in 4 or 8 port versions. They use BNC connectors for the antenna input and radio outputs. ScannerMaster also sells BNC cable jumpers to connect the multicoupler to the scanner.

Antennas: Get creative!

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Scannists are always looking for better antennas. The right anttenna can make the difference between hearing your target or not. It is often said that the antenna is more important than the radio it is connected too. One can spend more money on the antenna system that the radio, it is that important. Even more important that the antenna itself can be the coax that connects it to the radio.

That all being said, sometimes there is a way to improve your antenna situation without breaking the bank. In this spirit let’s look at a couple rules that can be broken creatively to get a decent antenna solution at a reasonable price.

Let’s start at the top. With antennas elevation rules all. The higher it goes the better, well most of the time anyway. Does it have to be mounted on the roof however? It might work quite well in the attic. Attic installations can also save on other matters. You usually don’t need fancy mounting gear for attic antennas, just hang it from a rafter or set it on the floor. Antennas in the attic are well protected from the weather and you can do installations in the rain without getting wet.

If you live in an HOA then you might not be allowed rooftop antennas anyway so the attic might be the only way to go. It is not without its problems however. If you have a metal roof or other metallic structures above they would be a problem. Watch for metal backed insulation sheeting, HVAC hoses and other obstructions.

If you live in rental housing or a condo you might not even have the ability to use attic antennas at all. If this is the case then you are stuck with inside antennas. There are a couple things you still could do. Can you mount an antenna on a balcony or patio? How about putting a mobile magnet mount antenna on a refrigerator or air conditioner? Hang a rooftop type antenna from the ceiling or mount on the balcony? There are a lot of different things you can do when limited by space, rules or conditions.

When mounting an antenna on the roof or in the attic be sure to use quality feedline (coax). For scanners either 50 or 75 ohm coax works fine. Avoid the use of adapters as much as possible and try to use the shortest amount of coax as possible. Having 30 feet of coax coiled up in a corner will reduce the effectiveness of the antenna dramatically.

As always, if there are more questions you can ask your friendly (well sometimes grouchy) scanner expert here at ScannerMaster!

Scanner Tip of the Week: Plural Radios, Single Antenna

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So you really got bit by the scanner bug and have several scanners to really keep tabs on the action. You really want to have a better antenna for them all but don’t want an antenna farm growing on your roof or your attic. What to do?

There are several good ways to share one antenna with 2 or more radios. There are also several bad ways. The bad ways might work good enough to hear some local stuff but that is about it.

The best way to share an antenna with multiple radios is by use of a Multicoupler. A Multicoupler has a connector for the antenna and 2, 4 8 or more ports for radios.Multicouplers allow signals from the antenna to pass thru it to multiple radios and prevents interference between them. “Active Multicouplers” have low power pre-amps in them to overcome the connector loss present whenever you put something between the radio and its antenna. “Passive Multicouplers” do not have the amplifier and will degrade the signal a bit.

Stridsberg makes several models of Multicouplers tailor made for scanners. Stridsberg is the most respected name in scanner multicouplers and ScannerMaster is proud to carry them. Up to 8 scanners can be connected to a single scanner antenna without loss. Check these out at https://www.scannermaster.com/Multicouplers_for_Police_Scanner_Radios_s/43.htm

If your needs are less stringent then you could use a splitter. Splitters are different in that they merely provide a way to share an antenna with two or more radios. These do not have the circuitry to reduce or overcome signal loss. Splitters can usually be used in the reverse way, to allow 2 antennas to feed a single radio, something that multicouplers usually cannot do.

One could just use coax “T” or “Y” adaptors but these provide no protection against interference or signal loss and are not recommended.

Regardless of the methods use there is no substitute for quality cables. Using high-quality coax, both for the downlink from the antenna and for the jumpers to the radios will reduce the loss and increase the signal strength. Don’t forget to use quality connectors if you make the patch cables yourself. Avoid the use of adapters as much as you can, everyone adds a little more loss to the line.

Scanner Tip: Indoor Antennas

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Chances are, if you have a scanner in the house, you have wondered if you need an outside antenna. While an outside antenna will almost always work better than an indoor antenna, sometimes that just isn’t feasible. If you live in a rental property, apartment or condo, or in an HOA restricted area you may not be able or allowed to install an outside antenna. Sometimes you just don’t want to go thru the work to do it. Maybe the spouse or significant other just won’t allow it.

There are alternatives, but as they are also compromises, they may work as well. They may however be good enough to allow you to listen to your targets. Depending on your unique situation, some or all of these ideas may or not work for you. Remember: There is never a guarantee that any of these ideas will ensure that you will be able to monitor your targets.

Let’s start with the simple ideas first. Your new scanner comes with a back of the set (or side of the set for a Home Patrol) antenna. This is usually a metal telescoping rod or a rubber-duck style antenna. Sometimes better reception may be had by a simple relocation or tilting the existing antenna. Maybe move the radio with its antenna closer to a window or away from the large metal objects will help.

The next step would be a better BOS (Back Of Set) antenna. ScannerMaster sells a variety of antennas, from direct replacements (if you lost or broke the one that came with the radio) as well as more advanced antennas. If you mostly monitor 700/800 MHz. systems a specialized antenna for these bands will work better than a general use antenna.

If these don’t help, then you may need a remote inside antenna like the Nomad. The Nomad is a wire antenna and is amplified (active). This allows you to mount the antenna in a better location and leave the radio where you want it.

The next step might be using a base station antenna indoors. ScannerMaster has several of these types. Basically this means a base station antenna with some sort of base to support it along with appropriate coax and connectors. These can be set up on a balcony or behind the drapes for aesthetic purposes.

You can also try a mobile antenna adapted to home use. Try a magnet mount antenna on top of a large metal cabinet, window air conditioner or balcony railing. Window mount antennas can be mounted on an apartment window just like you would on a car. Suction cup mounts work in a home just as well as in a car.

If you have access to an attic then you might try putting a base station antenna there. Try to stay away from large metal objects. If you have metallic shingle liners or solar panels they would likely interfere with your reception.

If you install an antenna outside, either on the roof or a tower, make sure to properly ground the installation to protect from lightening and watch out for electrical wires! Consider having them professionally installed. Use a high quality coax. Usually thicker cables work better at higher frequencies and longer distances. 50 or 75-ohm cable is fine for scanners since you will not be transmitting thru them. We will have a blog post soon all about Coax!

Scanner Tip: Antenna Connectors       

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Ever wonder why some scanners have different type of antenna connectors? Ever wonder what BNC, SMA or PL259 stand for? Read on and learn!

Most scanners these days have either a BNC or an SMA antenna connector. BNC’s are the ones with the round barrel (about the same diameter as a pencil) and 2 little nubs that you twist on and off to. SMA’s are smaller threaded connectors. Both SMA and BNC mounts have a small center conductor that is surrounded by a ground that is the barrel.

Why are these used for scanners? Well, it is because they work well at a reasonable cost. For years the BNC has been pretty much the standard scanner antenna connector, replacing the old “Motorola” antenna connect that had been around since dirt was invented. Some old scanners used the “UHF” connector. Almost all scanners over the last 10 years or so use either the BNC except for some handhelds that use the SMA.

Until scanners started to standardize on the BNC handhelds use a wide variety of connections, including several different threaded connectors, earphone style plugs and permanently mounted antennas. Most mobile or desktop scanners used Motorola connectors since these were also used on most car radios. Some old scanners used SO-239’s (the female part of the UHF connector), which were common for CB’s and other two-way radios. By the 1980’s many scanners started showing up with BNC’s, both handhelds and base/mobiles.

As handheld scanners shrunk in size some started having SMA connectors replacing the BNC’s. This save a bit of room but forced the manufacturers to produce new antennas and include adaptors. Some scanners that have SMA’s also come with a BNC adapter to allow you to use your existing BNC antennas and accessories, ScannerMaster also sells these adapters.

BNC’s is a bayonet type connection. These press in, with the nubs fitting into grooves. They get locked in with a slight twist and this provides a good physical and RF connection.

SMA’s are a fine threaded connection, the connector itself is smaller than the BNC, both inside the radio and out. With smaller radios, like the BCD396 series, this little bit of extra space helps. Since most scanner users already have BNC antennas, coax connectors and accessories, the manufacturers often include an SMA to BNC adapter to let you use all your existing goodies. Some high-end radio receovers come with “N” connectors. Look close at these and you might notice that a male “N” connector will fit onto a female BNC. They were developed by the same guy, the “N” in both connectors comes from his last name: Neill.

BNC connectors get their name from the bayonet layout (“B”), and the developers, whose last names started with “N” and “C”. SMA stands for “Sub-Miniature Type A”. There are also SMB and SMC but you will likely never see one.

Many two-way radios these days use “Mini-UHF” connectors, these are smaller versions of the venerable UHF connectors. “UHF” connectors actually do not work well on UHF frequencies. The original UHF connector was so named before WWII, when anything about 30 MHz. was a radio wasteland suitable only for hobbyists and experimenters.

All these connectors come in a Male or Female version. This is based on the center pin/socket. The connectors with a pin are male. The UHF connector is a little odd, in that it has common names for the distinct parts. The SO-239 is the female, used on the radio while the PL-259 is the male used on the coax. “SO” stands for Socket, “PL” stands for Plug. Most other connectors use the same name but with female/male parts, such as SMA, BNC and N.