Following a move to regional Queensland the Analogue TV was fine, and Digital TV changeover was in progress with the promise of Picture Quality.
Alas, what looked fabulous in the laboratory wasn't a reality for rural Australians, (probably fine for those living within a couple of kilometres of a transmitter tower).
The Digital signals travels as well/strongly as the old Analogue signal and the TV decoding the signal at the other end needs a strong signal.
When Digital dropped out and a NO SIGNAL icon appeared, it was time to solve the problem once and for all.
First Step: Replace the coax with quad shielded quality coax, and change the push-on TV connectors with screw on connectors.
This confirmed the signal degradation isn't in the house and it's time to work on the next link - the antenna.
As an amateur radio operator, propagation of signals are our thing and I could see the possibilities of a better Antenna design so....
The next step was research
The Telecommunications Authority maps colour-code anticipated signal strength but they can't allow for every dip and hollow that we may be living in, and should be taken as a guide only.
I researched the Phased Array VHF Antenna for Channels 6 - 12 and settled on the Big Ray 16 Element model - and it's quite a big - 2.4 metres [8ft] wide.
This Antenna is not a 'beam' so it is not 'pointed' at the Mountain - My antenna sits Broadside to the signal I want from Mt Goonaneman.
Mt Goonaneman transmits a 'vertical' signal so the images show a vertical alignment [the Aluminium Elements [bars] point up and down.]
OK, the larger part of the antenna took care of VHF signals now to get those pesky UHF Channels.
The 36 Element 'X-Type' Phased array was suited to my terrain and distance from the TV Transmitter tower. It sits at the top of antenna assembly with at least 450mm [18in] between the the 2 antennas. [see the Myths section. Myth 3 will explain this]
I needed to raise the antenna so I could get the signal over a stand of high gum trees blocking my line of sight. Always go as high as possible to give the signal the best chance of getting in.
A 6.5M galvanized steel pipe mast was fitted to the roof with 3 stainless steel guy wires to brace it as a precaution against high winds.
Next, another 6.5metre length of galvanized pipe was fixed a the mid-point of this 2nd pipe to the top of the fixed mast, allowing the pipe to swing down.
Antennas were fitted to the top of the swinging pipe and pulled upright with a rope. It is secured with a bracket to the fixed mast.
The whole things is about 13metres [42ft] avobe the ground and while this swinging method may not be needed very often, it is going to allow easier access.
The VHF Phased array retails for about $160
and the smaller UHF one costs about $110.
What should an installer charge you?.... How long is a piece of string? ..... This will depend on what steel you're putting on your roof, how much of the work you do yourself and a whole lot of other issues that only you and a reputable installer can chat about.
Do ask for a breakdown so you can see that he's charging fair prices for the two antennas and his labour.
Also get some references... go and see the people he's worked for... ask to see their TV picture... switch channels - I know it's a liberty but most people like to spread the word about good installers and we should be weeding out those who are not so reputable.
Let's talk about some Myths
Myth 1. Antenna salesman know their stuff.
That may sound harsh but... but when Bunnings puts up a display board and shows people what antenna to buy depending on their location - and it's WRONG!
... and when Antenna Installers go to old folks and charge them $600 to get Digital Antenna installed... and it's the wrong antenna, in the wrong position.
You tell me then... just because his shirt says TV Installer if he hasn't studied the propagation of signals and the fundamentals of antenna design why should we believe him?
.... We need to learn about signals, ask for references, talk to people who have GREAT Digital TV and all the other poor sods who don't...
Myth 2. That Digital TV signals are different and travel differently.
Nope. Whether it's the old analogue signal, or digital TV or your Wireless Internet or Mobile Phone... they are ALL radio waves just travelling at different wavelengths, and are governed by science. Don't mess with science and use an antenna to get the signal you need!
Myth 3. You can just stick antennas anywhere, near each other, it doesn't matter!
WRONG! WRONG! WRONG! And its quite another scientific fact why you can't do that.
If you cheat and stick everything in the wrong place one antenna WILL interfere with the other or BLOCK the signals that it is trying to pull out of the air.
Antennas need clear air around if you want to increase the signal you're chasing and they should stand out - away from - the mast they're mounted on.
The science states this is a quarter wavelength but let's keep this simple and say... keep about 450mm [18inches] from your metal mast/post and any other antenna.
Myth 4. The "long distance" Yagi Beam antenna which Bunnings sell is good for any distance!
WRONG - from Anecdotal evidence in this part of Queensland their long distance Yagi antenna is good for about 65km [as the crow flies!] from Mount Goonaneman [Childers]. Over this distance it is NOT a reliable antenna.
If you do live a substantial distance from your TV Transmitter you should be investing in a better antenna and that means a phased array... not a Yagi beam.
**There are probably more Myths but you get the picture, now you can ask.... What "fibs" have TV installers told YOU!**
There is some reference material in the Documents area which may help readers come to grips with the scientific theory and answer some installation questions
1. A sample technical specifications sheet on Phased Arrays: The link is UHF/VHF Phased array .PDF Document
2. Digital TV broadcast from Mt Goonaneman: Woowoonga Digital Broadcast Site Wide Bay Digital TV Channels
3. ACMA Signal Reports around Bundaberg Beaches: Compiled February 2012 BundyBeachesDVB.pdf
4. Radio Communications Handbook - Chapter 16: VHF UHF Antennas [File size 2.4mb]
5. A good Reference book: Understanding Digital TV [File size 3.6mb]