Monthly Archives: July 2015

Sources of pixilation in the Digital Antenna Installation

Technical Bulletin

When solving any television signal problem it is essential to have a clear understanding of the component parts.

We have the receiving device.  Signal in its simplicity is an energy.  The antenna is the thing that captures the energy.   So the question is: is it functioning as well as it should be according to recommended standards?   For the technician it is easy – he has a meter but the home handyman has to rely on his observation skills.  Are the connections all clean and solid in appearance?  Is the antenna pointing in the right direction?  This is a common fault as they are often positioned behind a tree which effects results when the wind blows.  Another question to ask is “ if I move the antenna could a find a clearer path to the transmitters”?

The next component part that is doing some work is the cable.  Mountings and masting simply hold the antenna up and play no part in the actual delivery of signal beyond making it possible for the antenna to work.

connec1Cable however is a vital piece.   What happens if you use a poor quality hose?  They develop leaks, the fittings on the tap or gun leak water.   It is exactly the same with poor cable and fittings.  Digital television signal demands quality cable and cable terminations.   F connectors have to be used if the shield (outer foil and wire and often up to 4 layers) is to be properly protected from interference.

Old devices like pal connections (push in fittings found still on the back of TV’s (for reasons I do not understand) are unacceptable when terminating your cable from the antenna.  You must use an F connector outlet plate.  This is the single biggest cause of pixilation in TV pictures.  The most fundamental repair is to change the outlet plate and install a quality connection cable from the outlet to the TV.   DIY kits are available. This solves some 70% of problems.

The splitters installed in homes are another source.   The Pal or saddle and screw variety (still sold and used by untrained people) are another No No!    Today splitters are available with twist on quality F connectors which home handyman can install if unable to call a technician to replace it for you.

The cable itself is another source of pixilation as cable deteriorates over time.  Solid soft copper inner conductors are useable in good condition where vhf frequencies are used.  UHF frequencies it is totally unsuitable.     VHF is any broadcast between 6 and 12.     Professional installers should always recommend that it is replaced as it will fail – it is a question of when.

I have seen it many times since the inception of digital television antenna installations.    It has on at least one occasion caused considerable upset with a customer.    We changed the outlet and short lead and suddenly pictures are good.  Customer delighted.  Simple fix and inexpensive.  Technician strongly recommends cable be changed as his meter told him something the customer could not see which was quite high errors in the signal packets and he had observed soft copper inner on the cable.   Customer said no that is fine and Technician did not insist a bit harder.    Pictures failed 3 months later (a bit more degradation of the cable) and now customer wants the job done but expects some sort of financial discount.   I mention this because it can look all good but it will fail with this type of cable – it is only a matter of time.

A copper inner is soft and bends easily.  Do not confuse with copper coated steel conductors which are very hard to the touch.   This is the preferred type of cable.  Known as RG6Quad but care should be taken that the cable being purchased is genuine and not a copy.

So if you are deciding on a solution you would start with:

Change the outlet and fly lead if inferior.   Even for the professional this is vital as it gives him a window to look at the performance of the antenna and the antenna system, if there are many outlets.   The professional technician would then check levels and bit error rates.   Then recommend what is needed as a result of his finding

Home handymen can do this step without a problem as it requires no roof climbing and no special tools are needed.

Sally Garden

Founder

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Signal Path affects and the natural environment

TECHNICAl BULLETIN

Signal Paths are almost always different.   Ever noticed how you can obtain one result in one location and then immediately move the digital television antenna and get a totally different result.   Why – obviously the path the signal has travelled is very different and you are able to see the consequence of that in the result obtained.

What are the key things to know about signal paths and why is this important to know.  As a professional television antenna technician it is valuable to know how signal is effected and what you can do about it.   This is what I know from years of observation and experience.

The higher the frequency the more predictable the signal.   The higher frequencies are impacted less by environmental manmade structures.  UHF signals penetrate and pass through with less impact on the integrity of the signal.  BER’s remain useable.    As you drop down the spectrum say into VHF Band 3 frequencies you do start to see consequences in your BER readings.   Power is often not impacted in a city environment as the signals are bounced from one object to another often with an amplification type of impact which often fools technicians because they expect good results and it doesn’t happen.   In another situation the BER’s will remain useable – signal path again is the answer as to why this happens.    It is important to start to understand the signal path as it can save many hours in testing throughout your career.  You are more component and the customer notices.

Some time back I visited a site where our technicians were having difficulty.  They were relative new to problem reception situations.    I scrambled onto the roof and the only thing I did was look at the signal path.   They had placed the antenna in a structurally good location but the path was poor which was immediately obvious to me.   I had them move the antenna some 4M along the ridge of the roof and at about 3M in height and bingo all good and problem solved.  It took me less than 5 minutes to identify the location.  What did I see when I scrambled onto the roof.   The antenna pointing into pine trees on the horizon which was only about 2 kilometres away due to the fact we were in a small valley.   Pine trees are a real barrier.   So we learn that pine trees are something to avoid.  They resonate and capture the signal rather than let it pass.  In energy terms they form a ridge so you have to get away from them, under them or over them.  My observation is they are even a bigger barrier in wet weather.

My father was in the Royal Australian Air force during the WW2.  He told me a story when I was a teenager playing with crystal sets.   His survival kit should he have to bail out was a 4” (100mm) nail and a length of single core copper wire.    The idea was to hammer the nail into a tree (with something) and send out a SOS.    All sounded pretty strange to me until when surveying during the upgrading of country services in outback NSW in the 80’s I observed a new phenomenon relating to UHF signals and believe it applies to VHF too but with less impact.    Signals travelling across granite ground as opposed to sandy ground will always do better.   The iron in the ground acts like amplification and keeps the signal going while the sand slows the signal down thus increasing the losses across the ground.  This was very clear from the many 1000’s of installations completed by my first company Skybeam Antennas when working in the sandy belt of Melbourne.   Signal levels were always lower and the lower the frequency the worse or more loss of signal resulted.   Channel 2 in those days was often quite difficult.   I have no real proof beyond observation but I believe the speed slowed to such a degree the noise in the signal became the dominant component.   This did not necessarily read as a lower DB.   Most meters cannot distinguish between a raw or wanted signal as opposed to a synthesised signal generated by noise in the signal path or circuit.

Going back to trees and their impact on signal.  Apart from pine trees other trees will impact on signal conditions but the ground they are growing in is more of a concern than the tree itself.   Clay has iron, magnesium, alkali metals, alkaline earths which all assist signal by contributing to the electromagnetic energy.   This in turn will affect the sap in the tree.     Further evidence of this was gained on the Murray River with the big red gums sitting in granite type soils.    I had a customer who had been receiving good television signals for years as a result of a DIY kit we put together for him and then suddenly he lost his pictures.    Lots of questioning resulted before I discovered the why.   The removal of rows of red gums on the side of the river.  The side the signal came from.   The rows of red gums where a natural amplifier and once gone so went the signal.

Getting back to the Royal Australian Air force they knew this and hoped the airman would ditch beside big trees in clay or granite type soils thus allowing the tree to act as the transmitter.

If involved in problem reception it is important to know something of the natural environment and how television signal travels.   Trees dependent upon the soil can be used to advantage.   treesTrees in sand type conditions become a deterrent.  The inertia of sands generally means lack of response and due to their hardness can reflect signal rather than resonate and amplifier.

If working in rural areas with some distance to transmitters a knowledge of the signal path is critical to getting results.   Decisions have to be made whether extensive testing is worth it and by understanding the environment you can make better decisions.   Next we will tackle the outcrops, hills and surfaces and environment of our cities.

Sally Garden

Founder

 

 

You need the right tools to be a professional

A very common error among the public and technician alike is to marry the correct connector with the correct cable – it is a precision thing. To reduce faults in digital television pictures the centre conductor and the shield must be connected in a precise manner. The shield connection in digital antenna installations is critical if great results under all weather conditions is to be achieved.
Gilbert Connectors and American company first bought the F connector to Australia in the late 1970’s. I was fortunate enough to be trained by the market leader and I know very few people really know how to connect a F connector correctly.
What has changed is not the technique but the cost of a good F connector for digital television antenna installations is about one tenth of what it was – so there is no excuse.
Following you will find an image of a device that has totally disintegrated for reason we do not exactly know but if you look carefully you will see the crimps have distorted the cable and this customer in the beginning did suffer with intermittent pixilation until the passive device became non-existent. This interruption to their television digital pictures was caused by the poor installation technique of the installer.
Note the distortion in the connector. The cable has been flattened suggesting it has been done with a pair of pliers rather than a proper sized crimping tool.
Good and consistent digital television results depend on doing each bit just right. That is the standard at Deeper Image Television

sally2

 

Deeper Image Television

After 25 years in Elgar Road Surrey Hills Deeper Image Television has a new home in Ferntree Gully.  The advancement and use of technology has made the necessity for a retail front both unnecessary and to some degree unaffordable for specialist services.   A factory environment today is more efficient to allow for storage of equipment, greater range of stock, training and generally greater space to move.

Our move is now completed and it is already more effective.   Prior to moving another important aspect of the business was addressed.   Our customer needs are changing as the technologies of internet and television move closer together sharing common needs like streaming of pictures.

Deeper Image Television has been responsible for many jobs where new technology was used with great success.   Following on in this tradition we addressed the falling competency of our technicians late last year with intention and commitment.    A good technician today requires many skills included amongst them is:  construction knowledge, good communication skills, good manners, ability to work at heights, ability to work in the dirt with spiders and slime, technical knowhow which has to include both RF technologies and IT technologies, small for tight corners but strong to lift a ladder perhaps 2 to 3 stories.   Then he has to be able to write, run test equipment and collect money.    When you take this apart this is extensive.   The failure of business to apprentice for a multiple number of reasons it now being felt.    We could not in one person find all these attributes and skills.

So we decided to go for a joint venture solution with another organisation.   An organisation that could offer the operational needs in one package while we concentrated on organisation, administration, marketing and training.

We are pleased to announce that Ryve Pty. Ltd. Is now that joint venture partner.    We have been in our new premises now for approximately 30 days and already staff have been added.  Many Audio Visual sets up in the home require a electrician for power cable installations.   We now have our own Electrician on staff which consolidates our capacity to service our customers both effectively and efficiently.

The installation team is now 4 persons strong and to-date dividing the executive responsibilities using two dedicated and competent organisation is a winning formula.

sally

Sally Garden

Founder

TECHNOLOGY CAN CREATE CONFUSION!

I have been in the industry for over 45 years and the pace of change leaves my head spinning, so I have no doubt the consumer must feel overwhelmed if technology is not a natural interest.    We find ourselves in many homes where good money has been spent on technology that does not get used.

This can often be caused by the shopper not really understanding what the sales person is selling and rather than plead ignorance go ahead and buy what appears to be a new beaut tool or aid to make life easier but in practise it turns out to be more difficult than expected.

This has given rise to the organisations offering to teach the shopper in the home how to use his or her equipment.  Children or grandchildren come to the rescue most often which is great but they seldom empower the adult to use the equipment from that point forward rather they get it going again until the wrong button is pressed once again.  Recent years has seen a great rise in this service call.

Deeper Image Television offer a consulting service based on a thorough knowledge of not only what is available but how to tease out what the customer really wants rather than overwhelming with a number of options.  This is a real skill and to do it successfully you need knowledge and people skills combined with a communication skill that can phrase the right question.

Deeper Image Television can do this and our customers both potential and existing are encouraged to use our wealth of knowledge to get some answers before making major purchases for their current home or a new home that is being planned.

Satellite, off air television, Foxtel, smart recording devices supplied by Telstra, Optus , Foxtel and others, IT networks both wireless or cabled are all technologies offered in the modern home.  To this you can add home automation, computer requirements and the integration of hand held devices – in other words quite a muddle.

Sally Garden

Founder

27th April, 2015.