Directional antennas are a good way of bringing in those weaker signals that we all experience when using scanners but to achieve something close to a high gain over a wide frequency range can involve a complicated design which creates large antennas even at higher frequencies.
The ultimate in a wide band beam antenna for use with scanners is always going to be the monstrous log periodic but the antenna alone is a big cash investment even before you start to look at installing a suitable tower and heavy duty rotator to mount the whole system on. Time, cash and available space don’t make this an option for a good majority of scanner hobbyists so we have to get inventive when it comes to setting up a focused antenna system.
Compact Indoor Antennas
Running a scanner of an indoor antenna will never be as good as having one mounted outside without having to deal with the signal loss that high radio frequency transmissions can suffer though walls and other solid structures but if this is the only option available to you there are some solutions.
The Ramsey 400-1000 MHz directional beam pictured on the left is probably one of the simplest ways to improve reception in any area from indoors. Made of a printed circuit board with the actual antenna laid out using the electrical tracks that are normally used to mount electronic components making it very durable without all the damage that can happen to traditional Yagi elements.
This PCB antenna does offer a small physical size with a reasonable front to back ratio with a noticeable gain but if you have the room to use something bigger you will get better results. A few plus sides to using a PCB type antenna is the ability to add more length to the elements for use at lower frequencies simple by scarping away the covering on the tracks and soldering extra wire on.
All Round Coverage and Antenna Size
Given enough space you can use any sized antenna you want inside or out provided there is enough room to point it in any direction. One of the other benefits of a quality directional beam apart from the increased gain in the forward position is the signal rejection onto the sides of the antenna sometimes giving the option to filter out unwanted interference that a discone will receive no matter how it is positioned.
For indoor a simple tripod that is light enough to pick up will work as a mount for a Yagi and with some low priced rotator systems available for use with lightweight Yagi antennas outside you don’t have to break the bank to get something up and running.
Building your own Directional Scanner Antenna
The makeup of a typical Yagi antenna is all about getting the measurements right before even thinking about putting it together. Working out the exact length of each element and the spacing between them will make any construction much easier than trying to make one on the fly.
A Yagi can be put together using common household tools, elements can be bolted and you can even get away without buying new material by slicing up old antennas you have hanging around. Because it’s such a widely used design in the field of telecommunications there is no shorted on the amount of information about the exact measurements and spacing needed to build a functional Yagi beam antenna along with websites like this Yagi calculator automatically doing some of the math for you.
Even though any directional antenna system is going to give you the edge over a standard wide band discone if your only interested in boosting that just out of range signal using them indoors automatically downgrades any performance at the VHF/UHF frequencies. We would always try to setup an outside antenna wherever possible rather than accept the poor performance and interference problems that using one indoors can bring.