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- getting good reception |
Where we broadcast BLU FM is licenced to serve the community of the upper Blue Mountains from Blackheath to Woodford. Other community radio stations are licenced to broadcast from Springwood to Lapstone. FM broadcasting We broadcast on the FM band. FM broadcasting ensures a high-quality signal that remains virtually free of interference. Stereo broadcasting We broadcast in stereo. Stereo gives greater presence and realism because it has two channels – the right and left. It is excellent for broadcasting music. You will need a stereo receiver to receive our signal in stereo. However, if your receiver in a mono receiver (such as a portable or a bedside radio) you can still listen to BLU FM but the sound will be mono. In areas where our signal strength is low, stereo sound can become distorted. You can often improve reception by switching your receiver to mono mode. Getting good reception Good FM radio reception depends on signal strength and the antenna you use. Signal strength depends on several things. The most important are the distance you are from our transmitter and the nature of the surrounding area (build-up, hilly, heavily wooded). A suitable radio is essential for good reception. In general, the better the quality of your radio receiver, the better your reception will be. If you have difficulty receiving our signal, the best place to start is with the radio and its antenna. Remember, with FM radio, no antenna means no reception. When you position your antenna, make sure you keep it well clear of electrical devices such as computers, refrigerators and power tools. Your antenna will work best if you position it so it faces our broadcast antenna, which is on the roof of the Blue Mountains City Council headquarters building in Katoomba. Good reception is usually achievable with the antenna indoors. However, in marginal reception areas an outdoor antenna will improve your reception. Electronics and hi-fi stores sell suitable antennas and they are quite inexpensive. They come with instructions for installing them and connecting them to your receiver. Troubleshooting If you are experiencing reception problems, the first thing to do is check your radio and your antenna. Check that the antenna you are using is suitable for FM reception, that it is on the side of your house that faces Katoomba, and that its cable is in good condition and is connected properly to your receiver. If you have a portable, make sure you extend the built-in telescopic antenna fully. Try adjusting the antenna, or moving the radio to different parts of the room to see if this improves reception. Antennas work better upstairs and near windows, but be careful of metal framed windows and make sure your antenna is not touching them or any other metal objects. Also, cut the antenna cable to length rather than coiling or bundling it. This will prevent it picking up unwanted radio interference. You must keep in mind that FM radio signals travel in a straight line. In other words, they cannot travel over or around large objects or penetrate them. Obstructions such as buildings or hills may be the cause of a weak FM signal. If you are using your television antenna for radio reception through a "splitter", see if reception improves by removing the television plug from the splitter. Electronics stores also sell amplifiers that boost the signal strength from the antenna. These are relatively costly, so check all other possible causes of poor reception before resorting to an amplifier. Stores will usually allow you to return an amplifier if it does not improve reception to a suitable level but check that this is so before purchasing. Interference from other stations Adjacent stations on the FM band can also cause interference. This is sometimes corrected by switching your receiver to mono. If it persists, the best solution is to aim your antenna more accurately towards our broadcast antenna in Katoomba. Interference from adjacent stations can become worse in certain weather conditions such as temperature inversions and heavy cloud cover. Problems using television antennas for radio reception If you are using a television antenna in the area east of Katoomba, it will usually be facing away from Katoomba and towards the city television stations. These antennas are designed to exclude signals from the side and rear. You may get better results with a dedicated radio antenna. Outdoor FM antennas are not expensive and are easy to install – they clip onto your guttering. Car radios are often fitted with a facility to search for the strongest signal. This can be annoying in hilly areas such as the Blue Mountains, so try switching it off. Then, search manually for the BLU FM signal on 89.1. The simplest to install, the most effective and the most economical antenna for FM radio is called a dipole. It is usually supplied with FM radio receivers but can be purchased at electronics and hi-fi shops. Put it in a vertical position rather than horizontal for best radio reception. How to make a folded dipole antenna Use television ribbon cable. To receive BLU FM cut a length to 1.8 meters*. Fold the cable in half to find the halfway point and mark this spot. Next, measure exactly 80 cm from this spot in both directions. Now, at these two points, cut the plastic shield and strip them from these two points to the ends of the cable. Be careful not to cut through the copper wire. Twist the ends of the copper wire together. This makes a folded dipole of 1.6 meters.
Now, you can tack the dipole to a light wooden batten (e.g., 20-25 mm wide by 5-9 mm thick by 1.7 meters long. Stand or hang the dipole vertically inside the house or, if it improves reception, hand it outside. You can hang it from the guttering with a brass cup hook screwed into the end of the batten. Finally, connect it to your radio receiver. Attach it to the 75-ohm connectors. (Note: if your radio has RCA sockets you will need to connect the lead in ribbon to a 300-ohm to 75-ohm balun and plug it into the sockets.) (Acknowledgement: These instructions are from an article by Neville Williams published in Electronics Australia, June 1976.) *The formulae
for determining the dimensions is L=142.5 divided by f (where, L
is the length of the ribbon cable and f is BLU FM’s frequency 89.1
MHz.). Official website for Blue
Mountains FM 89.1 |
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Tips
on receiving quality reception
At the center point that you originally
marked cut away the plastic shield on one (only one) of the copper
wires. Take a suitable length of ribbon cable (long enough to reach
your radio receiver) and twist one wire to each of the center wires
of the dipole (see above diagram).