Better television reception Drouin by Andrew Lacey, founder and director of Antenna IQ

 

 

Drouin is a beautiful area to live. Unfortunately, it is over 50 kilometers as the crow flies to Mount Dandenong the main television transmitter for Melbourne. Likewise, the regional channels come from the Latrobe Valley transmitter which is over 70 kilometers to Melbourne.

This leaves the average viewer with what is often an undependable viewing experience. So what can be done?

There are a range of factors at play. The first factor is distance. For obvious reasons, there isn’t really much that can be done about this, other than installing a local transmitter. This isn’t going to happen, not in the immediate future anyway.

The second factor is quality of equipment. Your television antennas, cabling, amplifiers, filters and distribution equipment all need to be in optimum condition. For most customers this is not the case. There are things you can do to ensure your leads are in optimum condition. Most televisions have a manual tune/signal condition mode as listed in your tv manual (Samsung generally don’t have this feature) you can wiggle the leads whilst checking the signal quality. If this causes the picture to drop out, replace your flylead. This will eliminate one of the cheapest and most often faulty parts of an antenna system.

Many new aerials are not band optimised. What this means is that your aerial may be picking up a signal at least four times weaker than an equivalent, well engineered european antenna.

Quality of amplifiers. This is very important. The main figure that you’ll hear quoted when amplifiers are talked about is gain. Gain won’t help you if the signal is not within the minimum input level of a particular amplifier. Amplifier intermodulation distortion is a more reliable figure. Most television amplifiers will also amplifiy LTE, FM, pager signals. A spectrum analyser and skilled technician can assist in locating the cause of interference and antenna choice, location, and filters, or amplifiers with better filtering can assist with these issues.

Faulty or intermittent amplifiers. These are often best identified by a competent technician, however experience has been a strong guide on diagnosing these issues. Some amplifiers are generally unreliable beyond a few years of use. One amplifier that is recurrently obvious is the alcad AM126. When working these are a noisy awful thing. As they fail they create harmonics and attenuate signal making a weak signal significantly worse. If you have one, whether it has already failed or not, get rid of it. If it’s a white box on the roof with a 22vac amplifier almost every time it’ll be one of these garbage products. There are much better amplifiers on the market.

Incorrect cabling. This is a very broad area. Most clients like to think of an antenna system as a receiver that picks up signal and an amplifier that boosts it. The reality is very different, particularly with cabling in a system. Many houses and commercial properties are wired with poorly shielded coax that is not manufactured to 75ohm. Other times the coax is run parallel to power cables, allowing noise and potentially voltage to induct into the coax. This will degrade the signal significantly.

Faulty splits and joins. Without proper impedance matching and poor isolation, the viewer can have some channels work and not others. Sometimes this is not the result of insufficient antenna signal. A tuned notch can have the same effect. A signal has it’s own tuned length, what can happen is that when a length of coax is simply twisted together to add another tv point without any specific quality tap, or splitter, the length of a coax run can effectively work as a filter, or a notch, filtering out some, not all frequencies. This effect is often varied and unpredictable. Moreover the poor connections often create reflections in the coax run, effectively corrupting signal quality. Always ensure correct splitters and taps are used and the system is locked to 75 ohm.

In Drouin, there have been many new cellphone towers installed. This creates a new problem: LTE interference. This as a result of the digital dividend, is the sell off of channels to the mobile network providers. This is a good thing: faster mobile broadband data, better and more stable phone call quality. These benefits have been offset by some interference issues. We carry a range of antennas, amplifiers and filters to better cope with these issues.

Narrow band antennas. 10/4046/r, 20/4046/r, 10bl5, are just a list of example products that can have issues with gippsland channels. In this post I’ve emphasised the benefits of narrow band antennas but there is a down side. When the digital restack happened in 2014, the transmitter frequencies for country channels from the Latrobe Valley transmitter were moved to block B. What this means is that if you have an antenna that was cut for the older higher frequencies, the technical equivalent of a Ferrari, it is now an old Datsun. A narrow band antenna has fantastic in-band reception, but out of band the signal will be at least 10 times, or as much as 10dB weaker. In these instances replacing the antenna is cost effective and a very simple way to improve signal.

Optimal location. I’ve personally seen many systems on 20 foot masts not working. Absurd is the only way I can word it. A tall mast exposes the antenna, the masting, guy wires, your roof, house and anything underneath to extreme wind loads. My advice to get things working well, is by finding the best signal on your roof using excellent equipment and correct installation. Any of the above faults will kill your television reception. Only a professional with a high speed digital spectrum analyser will find the best position on your property for best available signal.

Of course there are hundreds of potential issues that can effect television reception. This article is intended for general advice only. We recommend you only use a trained, insured, competent professional. Andrew Lacey from Antenna IQ can be contacted on 0427004604 or follow the contact us button on the navigation bar.