South Africa is blessed to have public to air broadcasts. We have free channels that we have to pay for (it’s the right thing to do) and we have more ads per half hour show than actual content.  On top of that we generally have poor broadcast coverage.  Large parts of the country for example only receive SACB 2!

There are a number of things you can do to get acceptable signal though.  The basics are listed below:

Aerial

No matter what you do to the signal after this point, if you have bad signal in your will have poor picture out.  Invest in a high quality aerial.  Things to check for:  The “big grid” part of most aerials are the reflectors the bounce  the signal onto the receiver.  The receiver is connected to your cables that carry the signal.  The bigger the grid the more signal it reflects but it can also reflect more interference. 

If you pick up interference like ghosting you might have to switch to a directional aerial.

The more directional the aerial is the less interference you will pick up but the more accurately you have to point it.  To top it off you might then exclude a channel.  So go through a process of trial and error until you find what works. 

Most areas you can get away with using a UHF aerial but some, especially more rural areas, like Pinelands may require a VHF aerial as well.  You would then need to combine the signals.

UHF stands for Ultra High Frequency and is generally a better signal that VHF.  Mainly used by MNET, SABC 3, SABC 1 and E-TV.

VHF stands for Very High Frequency and is generally a worse signal that UHF. Mainly used by SABC 2.

The channels can be different for your area.

Aerial placement

You will really have to experiment and see what works best but here are some tips. Aerials should be mounted as high as possible, pointing to the broadcast tower closest to you.  Putting the aerial inside your roof will protect it (cables / booster) from the elements but you might lose some signal strength, rumored to be more when your roof is wet.  It might also pick up more interference – from your geyser/ fridge  for example.  Try to have your aerial closer to your receiver so there is less cable, this penalty can be minimized by using good quality cable.

Signal boosters

These should only be used if you have good signal but your have long cable segments or you are splitting the cable.  If you amplify a bad signal it will only make it worse.

Cables and connectors

Use only top quality cable and connectors.  The loss of signal due to cable resistance is called attenuation.  Better cables and connectors have lower rates of attenuation so more of the signal makes it to your receiver.   You will also have better shielding so external magnetic fields would have less of an impact.

Types of interference that is common

Ghosting:  A second image appears slightly offset to the main image.  This is caused by the signal being reflected and arriving at your aerial slightly later.  It could be cause by big buildings or geographical features.  Directional aerials can help here but moving your aerial around can also help you find a better spot.

Slanting Streams:  Multicolored interference streams slowly scroll across your screen.  This is weak signal and interference from a constant source like your fridge, PC, Hard drives etc.  You might have to move your aerial, but the interference could also be jumping on to your cables as they go past something electronic.

Most other issues are caused by weak signal and can be rectified by using a proper aerials, cables and connectors.

Remember the weather.  Signal is normally better at night when it’s clear, worst on a rainy day with lots of wind.

MNET Decoders

These boxes are amazing.  There are no moving parts to them, but they give more hassles than any other device. 

The MNET decoder is a receiver so you need to have good signal coming in to it.  It then also outputs a signal onto the cable.  You need to set your decoder not to clash with any of your other channels. This could be a problem if you are getting a decoder that used to be set up for another area.  I have seen decoders give all sorts of funny problems.  Best bet here is to get a new decoder and keep the exchange warranty going.

Signal strength is important here since the box needs to have enough clear signal to be able to decode it.  Interestingly and annoyingly you can see effects of the encoding.  Since your MCE shows all of the broadcast and not just what TVs are set to display you may notice a white line on the left of your MNET channel.  See the images below comparing the picture during open time and during normal MNET broadcast.

Open Time

 

 

 

Not Open Time

 

 

 

For this reason I adjust my TV out display to cut of the far left of my screen so I don’t see the annoying white line.

Thanks to Etienne for submitting this article.