Home Aerial Installation Report

What they said about us.....

"The robust installations are a good advert. A no-nonsence approach."

Tim Jenks
Senior Executive
Confederation of Aerial Industries

"This is a company that has been built up on a solid reputation.

I am fortunate that I know Woking Aerials work, his reputation goes before him. Any person employing Woking Aerials is assured of a job well done.

Again being able to see work close up shows that Alan provides a service which is to be envied.

The system viewed by me was very impressive...."

Chris Glover
Confederation of Aerial Industries

"This assessment was carried out as an NVQ assessment session.

I observed Alan, visit a domestic property, qualify the customer, fault find/diagnose the reception issue, and install a complete new aerial system.

This was done to an exceedingly high standard."

Kevin Dawson
Assessment & Training Executive
Confederation of Aerial Industries

Kevin has been the UK TV expert for ITV's 'House of Horrors' & BBC's 'Rogue Traders'

                   City & Guilds Qualified

Surrey County Council Trading Standards Approved

Aerial Installation Report

The following is a report I compiled on behalf of the customer for his submission to Trading Standards. The aerial company was at the time of installation and still is a member of a Trade Association whose members are supposed to work to a Code of Practice.

Customer: Mr Dxxxxx

Site: Send, Woking

Work Order Details:

Upon receiving a telephone call from 'the customer' and at his request, I attended site. The customer’s complaint was that, although he had recently had a new aerial installed by another company, his digital reception was intermittent with the picture breaking up, freezing and pixilating. I viewed the picture on several digital channels and witnessed the picture break up or freeze.

Local Observation:

Having installed locally for over 30 years I knew that the reception at this property should have been quite easy to obtain. A view from the front bedroom window (Fig 1) showed me that direction to the transmitter at Crystal Palace was clear and trouble free.

A clear line of sight was present from the bedroom window.

Fig. 1 A clear line of sight was present from the bedroom window.

The Aerial:

The ‘new’ aerial had been fitted in the loft. The roof construction is of timber trusses and rafters, covered in bitumen based felt, battened and covered with concrete roof tiles.

The components for the ‘new’ aerial were a Triax DM15, (I presume that it is a DM15 because that is what has been itemised on the receipt, I do not purchase or stock this model, although I was able to count that it did have 15 elements), approximately 2’ of 1” mast, a 6” wall bracket, approximately 10’ of coaxial cable, 2 x ‘F’ Connectors and an ‘F’ barrel joiner.

The aerial had been fitted by means of attaching the wall bracket to the roof trusses, attaching the mast to the bracket and the aerial to the mast. The new piece of cable was then attached to the aerial at one end and to the existing aerial downlead at the other by means of two ‘F’ type connectors and an ‘F’ barrel joiner.

The front element of the aerial was touching the roofing felt, the masts had been shortened by bending to and fro until it had snapped, an equipped engineer would have used a hacksaw. The installation can be seen below in figures 2 – 5.

The 'loft' aerial. The 'snapped' mast.
Aerial elements touching roofing felt. Aerial elements touching roofing felt.

Figs. 2 - 5 A very poor aerial installation.

Existing Aerial Test:

Signal tests were carried out on the existing installation by unscrewing the ‘F’ joiner and connecting the lead from the aerial to a Promax TV Explorer, TV & Satellite Signal Analyser.

The signal level for Channel 34 (Digital Multiplex C) is shown in Fig. 6a and the Carrier to Noise Ratio is shown in Fig 6b.

The signal level for Channel 34, 43.2dBµV Carrier to Noise level for Channel 34, 6.7dB

Fig 6a

Fig 6b

Whilst some channels performed within the required limits, Mux C had a power level of 43.2dBµV with a Carrier to Noise Ratio of 6.7dB. This signal was measured at the aerial on the end of the ‘new’ piece of cable supplied by XXXXXXX Aerials.

Further signal losses will occur the further the signal travels down a length of cable depending on frequency. As a rule of thumb, using a Benchmarked cable, we calculate the loss to be 19dB over 100 meters at 860MHz, lesser quality and old cables tend to have greater losses.

Over a period of time coaxial cables fail to function as well as they do when new, aerial cables degrade with age, whilst not always visible to the naked eye. Signal losses tend to increase with the age of the cable. The required signal levels at the television or Set Top Box, and those laid down in the CAI’s Codes of Practice are a minimum level of 42dBµV on Mux C which is transmitted in 16 QAM with a C/N of greater than 23dB. (>23dB) Signals broadcasted in 64 QAM require a minimum level of 45dBµV with a C/N of >26dB Allowances must be made for signal fluctuation which can occur with the changes in the atmospheric pressure; these changes could be ± 3dB.

The original 14 element aerial had been left lying on the loft floor (Fig. 7) and a test for comparison was made by connecting a short coaxial lead to this original aerial. The original aerial I believe was manufactured by Aeriallite and was approximately 30 – 35 years old. Aeriallite are no longer in business.

The old existing aerial had been dumped on the loft insulation.

Fig. 7 The old existing aerial had been dumped on the loft insulation.

Conclusion of Signal Tests:

There were insufficient Signal Levels or the correct combination of Carrier to Noise Ratio on some of the Digital Multiplexes to guarantee the continuous viewing of television pictures, no guarantee could be given that they would not be interrupted periodically resulting in a loss of picture, sometimes for extended periods.

Suitability of the existing aerial:

Over the last few years or so the CAI together with aerial and cable manufacturers and the DTI have established a benchmark to which aerials and cables are tested for digital compatibility, once an aerial or cable has passed these tests the aerial or cable is awarded a Benchmark Certificate and a Benchmark List is published for trade and public inspection. As one would expect the Aeriallite aerial would not be on that list, but neither was/is the ‘new’ DM15 aerial.

Woking Aerials only install aerials and cables which have passed the benchmark tests, these we deem to be ‘fit for purpose’, by the technical standards published today.

Further signal tests were made using a Benchmarked Triax Supergain 18 element Wideband Aerial on the roof of the property, adjacent to the chimney. It was found that there was more than the minimum signal requirement outside on the chimney and the Carrier to Noise Ratio was above the required minimum. Having discussed all the findings with Mr Dxxxxx, he agreed to have this new aerial installed permanently. It was fitted to the chimney using a standard ‘chimney lashing kit’ and a standard 5’ mast. A new, continuous length of Benchmarked Cable (Italiana Conduttori srl QF100) was then run from the aerial to the socket on the lounge wall.

The outside aerial mounted to the chimney.

Fig. 8 The outside aerial mounted to the chimney.

Since our new installation has been installed, Mr Dxxxxx has reported no further reception problems.

I advised Mr Dxxxxx to seek legal advice over the previous poor installation being as he had been charged £146.88p for an installation which not only did not work, but was not 'fit for purpose'.

Page 2. The Wrong Advice. Page 3. Signal Analysis, The Results.