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Vehicles Causing Interferance

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#1 GTS monaros

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Posted 19 February 2012 - 07:04 PM

Hi all,

new to your forum,my name is craig, and a friend recommended this forum for advise.

I live north of Tamworth,and seem to be limited for expert help out here,the local TV guy said my signal is very good,but was no help at all to the interferance from all types of vehicles and mowers,trucks,cars bikes,anything with an engines causes pixilation,and loss of signal on prime and ABC channels.

I fitted a new arial,booster, coax,have moved the arial to a different location,nothing changes,today there was no traffic here all day and picture was fine,then tonight as everyone is returning to town the trouble starts,the arial seems to pick up cars etc from kms away.

thanks for any help in advance.

cheers craig.

#2 Owen

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Posted 19 February 2012 - 10:51 PM

Gday, the aerial booster amplifies noise and interference as much as it does the TV signal, for digital TV that can be bad and make the situation worse.
Try removing the booster or lowering the gain and see if that helps, less is sometimes more. :D

#3 digitalj

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Posted 20 February 2012 - 01:57 AM

Even though the signal may be good at the current location, there may be another location on your roof that has better quality signals which may help to beat this interference.

What type of antenna do you have? If it has any elements which are well over 1m long, then swapping it for another antenna that is designed only for the frequency bands you want will go a long way towards keeping impulse noise interference out of your distribution system.

#4 M'bozo

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Posted 20 February 2012 - 07:49 AM

G'day Craig,

I live north of Tamworth


Australia is big. Not as big as the universe, but still big. North of Tamworth could be a long way from anywhere, so it would help to narrow your location to perhaps a road or something. This makes it easier to find to assess the possible problem.

This site, mySwitch can give you an idea of reception conditions for your area, after you put your address in. It may assist you.

and seem to be limited for expert help out here


Surprising, there seems to be a few installers that service your area, however, I'll take that as read.

the local TV guy said my signal is very good


Not sure what that means.This can only really be determined by taking measurements of the signal at the antenna. Has this been done?

anything with an engines causes pixilation,and loss of signal on prime and ABC channels.


That tells me you are having trouble with VHF channels. This typically occurs when the signals arriving at the antenna are weak. Weak VHF sgnals can be corrupted by electrical interference generated by, amongst other things, vehicles with spark ignition systems. Your UHF channels, as you have observed, are less likely to be affected by this type of interference.

I fitted a new arial


Have you a manufacturer & type number for this aerial? Also, what is the model number of the masthead amplifier (booster) you are using?


The mySwitch site referred to earlier shows there is a transmitter with all signals on UHF, that may cover where your house is located.


A competent installer should be able to suss this out for you.

If it is possible to get your signals this way, it would be preferable to your current set up.

This may be as simple as turning your antenna towards Soma Mountain, & rescanning to see if you can get signals from there. Worth a try, just be aware, that at UHF, the type of antenna, & location on the property, can be critical for good reception.


By the way, a more suitable sub-forum for posting further questions could be here

Marc.

#5 alanh

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Posted 20 February 2012 - 11:09 AM

GTS Monaro
http://www.dtvforum....showtopic=14026 "Get the best reception - Regional NSW"
Your problem is impulse interference
The amplifier needs to be designed for band 5 only. This will include a filter which removes impulse interference. You also need to use quad shielded RG6 cable throughout the installation.

AlanH

#6 GTS monaros

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Posted 20 February 2012 - 06:08 PM

Thanks for all the feedback guy,s appreciate,

Owen,i was wondering how to adjust the gain,is it in the thingy up near the aerial?

Marc,thanks for picking through my comments,i,ll try to explain my self a bit clearer for you,50kms north of Tamworth,but not as far as Cairns.


Thanks for the link Marc,

There are installers around here,but that doesn,t mean they know jack about what they are doing,locals and word of mouth has proven this,6 toes out here bud.

The guy that came, climbed up to aerial and attached his gizzmo,which made strange noises,and he was happy with readings.

Compitent installer,we really could do with one of those here.

alanh,

from my reasearch on the computer,i think you are thinking along my lines,but that doesn,t necissarily mean we are right,but i have a filter ordered,and what does band 5 mean?,and i,ll make sure the RG6 cable is here.

Anyway i have a Kingray power supply,with a power injector,and i hope the picture i try and load of the aerial works.

thanks heaps craig.

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Edited by GTS monaros, 20 February 2012 - 06:11 PM.


#7 digitalj

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Posted 20 February 2012 - 06:45 PM

That antenna looks like it has either band 1 or 2 elements (the longest ones) as part of it, these are the elements which are most likely to pick up impulse noise interference. If receiving from Upper Namoi, you need an antenna for Band 3 and either band 5 or band 4+ without any band 1 or 2 elements.

You may also potentially be eligible to receive VAST via satellite. This can be checked on the myswitch website.

#8 alanh

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Posted 20 February 2012 - 06:55 PM

GTS Monaro,
The antenna you are showing is not the right one for Mt Soma.
Since you are not in Tamworth your installation is for Mt Dowe which covers the Upper Namoi and is much more powerful than Mt Soma.
ABC8 NEN9A (Prime) SBS36 NBN37
NRN40
Southern Cross
Channel 8 & 9A are band 3 and the others are band 5.
There are more sensitive band 3 antennas than yours around.
However sometime prior to the end of 2014 these channels will be changed to be either channels 6, 7, 8, 11, 12 (band 3) or all UHF. So I would not spend a lot of money until this is known. If they go UHF your problems will disappear, if they make them all band 3, then you should replace this antenna with a high gain band 3 antenna only and perhaps install a filter between the antenna and the masthead amplifier.

AlanH

#9 GTS monaros

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Posted 20 February 2012 - 07:12 PM

Thanks guys,

This is a real pisser,the so called pro at tamworth,i told him i live at Manilla and wanted the best components for my town and seems i,ve been given the wrong antenna.

Didn,t realise it was so teckno,i thought all antenna,s did the same job,I need to study this some day,but for now you guys are a great help to me,thankyou.

Do you think the filter is worth a try for now?

This may sound doggy,but can i modify this antenna?like chop of bits.

craig.

Edited by GTS monaros, 20 February 2012 - 07:15 PM.


#10 M'bozo

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Posted 20 February 2012 - 07:45 PM

There are installers around here,but that doesn,t mean they know jack about what they are doing,locals and word of mouth has proven this,6 toes out here bud.

Ditto, and two heads where I am to boot. :lol:



attached his gizzmo,which made strange noises,and he was happy with readings.

Would like to know what the readings were, particularly the VHF channels you're having trouble with.



but i have a filter ordered

Probably a waste of time. Your problem is most likely occurring because the interference is coming in at exactly the same frequency of the channels you are trying to receive. A filter will do jack **** in this case.

The only way to possibly overcome this issue is to improve the wanted signal by using a more sensitive antenna, or raising it higher on the mast. There may not be enough signal from the transmitter to achieve this in any case. Sometimes, you can get lucky.

The antenna picture you have posted appears to be of a Hills SMX14WB, SMX14B4+ or clone thereof. In a high signal environment (read closer to the transmitter) this antenna would most likely be suitable.

In your situation, you may even need separate VHF & UHF antennas to get optimum reception from Mt Dowe.

mySwitch suggests UHF reception from Soma Mountain could be patchy : Nothing to lose, however, by swinging your antenna to that transmitter to see if you can get anything from there.

#11 digitalj

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Posted 20 February 2012 - 07:50 PM

A filter won't really fix the problem completely. Impulse noise interference unlike other types of interference can't be filtered properly because it spread across a really wide range of frequencies which includes the ones you want to receive. A filter can help improve the Signal to Noise ratio though by removing other out of band signals like AM, FM, CB radio, etc., the higher SNR would go someway to helping defeat the impulse noise interference but not completely. ultimately the best way of keeping it out of your system is to have an antenna which is designed to only receive the bands you want.

#12 GTS monaros

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Posted 20 February 2012 - 08:12 PM

2 heads,hehehe

now you are guiding me,i,ve had a look on the link and it says basicly the problems i,m having is normal to my address,WTF,if your going to improve TV why give us this ****.

And the vast thingy,isn,t available for our area.

My neibour has similar probs,the guy up the road has a weird antenna,something that is looking to the sky,maybe the vast thing,i might call in tomorrow and ask.

What would be the ultimate antenna for me?This pixilation and a screech sometimes sends me over the rails,i carn,t stand it.

#13 digitalj

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Posted 20 February 2012 - 09:38 PM

Myswitch suggests you may be able to get a signal from Armidale.

#14 alanh

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Posted 20 February 2012 - 11:15 PM

GTS Monaro,
Your pro sent you the right type of antenna for Manilla. It may not be sensitive enough, but it is the right type.

You have the right type of antenna pointed at the region's main high powered transmitters. It is just that you do not have quite enough signal to overcome strong impulse interference. You could try an UHF phased array pointed at Mt Soma but there is no real guarantee it will work any better. If Mt Dowe eventually goes all band 3 then a CA16 phased array would remove your problem, however these are large expensive antennas. If they go to all UHF then a high gain UHF phased array would be best.

The transmitters in Armidale are low powered and designed for the town and its surrounds only. Digitalready does not suggest Armidale, only Tamworth.

A Kingray MH-FL3BPF should be set to pass H and U only and inserted between the antenna and the masthead amplifer. This then may allow you to increase the gain of the amplifier if the signal is free of impulse noise. This will then make the signal stronger than any impulse interference picked up in the cabling between the amplifier and the TV.

AlanH

Edited by alanh, 20 February 2012 - 11:17 PM.


#15 GTS monaros

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Posted 21 February 2012 - 04:55 PM

Hi alanh,

googled the kingray MH-FL3BPF and got nothing,what is this a filter or something else?Is this thing adjustable to set to pass H and U.

I,m guessing there is some kind of adjustment in the box up near the antenna,is this the mast head amplifier your talking about?

cheers.

#16 alanh

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Posted 21 February 2012 - 05:41 PM

GTS Monaro
http://www.kingray.n...l3bpmh-3_im.pdf
The masthead amplifier is in a box under the antenna. It is powered by a power inserter near a TV and the power goes up the antenna cable.
The gain control is within the box under the antenna. You will see that this filter uses F connector plug on the ends of the cables.

Any corrosion will also make the impulse interference worse. On the screw on connectors it looks white.

AlanH

#17 GTS monaros

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Posted 21 February 2012 - 08:24 PM

Hi alanh,

Just climbed down in the darkness for the 5th time adjusting,there were several part numbers and a black mark next to the number MHW34F,i tried winding the screw back as it was fully in the clockwise position,it doesn,t seem to make any difference,At the moment its in fully clockwise.UHF mode i think it was.There is only 3 conections uhf vhf and return to house.Everything is new looking no corrosion.

After reading my masthead amplifier,sounds like this could be the problem,there is a police station not far,a large aerial like a CB bloke,trucks the list goes on for things to interfer with this amplifier,as it is not sheilded.

What do you think?

craig.

Edited by GTS monaros, 21 February 2012 - 08:37 PM.


#18 alanh

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Posted 22 February 2012 - 01:48 AM

Craig,
I suggest you ask a police officer at the station to make a test transmission when some one is watching the TV to see if the TV pictures and sound breakup when the police officer pushes the transmit button on the microphone. This will identify if this is the cause.

As far as ignition systems go, most two stroke motors do not have any suppression on their ignition systems. Most cars use a set of carbon filled ignition leads as part of a suppression system, however some people replace them with ignition leads containing copper wire. Thise radiate lots of interference. So watch to see which vehicles give problems. Diesels should not give any problems because they don't have ignition systems.

The reason why the gain control has little effect is that the UHF gain is near the edge furthest from the connectors is for all stations other than ABUN and NEN (Prime). The adjuster closer to the connectors may make Prime less reliable than ABC or vise versa. Turn both controls fully clockwise.

AlanH

#19 GTS monaros

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Posted 23 February 2012 - 05:46 PM

hi Alan,

I,ve ordered the kingray mast head amplifier you recomended and i,ll let you know how i go,

Our police are rarely at the station,i was also wondering if a electric fence would cause this constant interferance?It is across the road.If so i,m hoping the new fully shielded amp will solve the problems.

#20 GTS monaros

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Posted 23 February 2012 - 07:02 PM

Just got a phone call, it will be here in morning,i,ve got my RDO,so i,m gunna have a go at it.Could you please explain what i have to do,so do i fit this between the mast head amplifier and antenna,and do you know which plugs to plug into,

Earlier you said should be set to pass H and U only,what does this mean?

Appreciate any help,

regards craig.

Edited by GTS monaros, 23 February 2012 - 07:13 PM.


#21 alanh

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Posted 23 February 2012 - 11:45 PM

Craig
L = RF channels 0 - 5A which have only been used for analog TV
H = channels 6 - 12 = band 3, for ABUN8, NEN9A (Prime)
U = channels 28 - 69 SBS36, NBN37, NRN40 (Southern Cross) will eventually will be used for all transmissions from this site.
The device you have ordered is a filter only. It needs to be between the antenna and the masthead amplifier. This will means that the masthead amplifier will not amplify the interference.
Connect your antenna to input 3 and switch the switches to the B position. (Top right diagram on the instruction sheet)

Electric fences can be very good sources of interference due to sparking. Firstly see if you can get the fence switchoff briefly and check the reception. It is essential that the fence power supply is well earthed using a short wire to a metal stake into damp ground. and that the vegetation is kept low around the fence. In addition the electric fence only have wires radiating away, no loops are allowed.

AlanH

#22 GTS monaros

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Posted 24 February 2012 - 06:15 AM

hi alan,

I walked the fence the other morning and there was no shorting,and no vegitation at all.When you say looping i did notice alot of what i think is looping where the fence leaves the main line and comes back on it self around trees,is this the looping you would be talking about?Also not allowed,does this mean i have rights for him not to be interfering with my reception?

Thanks again for your help,

regards craig.

#23 alanh

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Posted 24 February 2012 - 08:26 PM

Craig.
The wiring once it splits should not rejoin again, otherwise a current flows causing a stronger signal. An effective earth on both the power input and the earth on the output should really be a stake of atleast a metre long preferably where it is damp. (Not inside a shed for example)

AlanH

#24 nbound

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Posted 24 February 2012 - 09:24 PM

That antenna looks like it has either band 1 or 2 elements (the longest ones) as part of it, these are the elements which are most likely to pick up impulse noise interference. If receiving from Upper Namoi, you need an antenna for Band 3 and either band 5 or band 4+ without any band 1 or 2 elements.

You may also potentially be eligible to receive VAST via satellite. This can be checked on the myswitch website.


Thats a Topline TL14UV Combo Antenna (or something very much like it). It is only Band 3 as far as im aware, the big arm halfway down the body is actually fake, the two plastic covers halfway down the cover a gap, the element only reaches to the plastic covering. Its a pretty average antenna, only good for somewhere with good coverage.

Given the predicted (digitalready.gov.au) signal coverage you will probably need dedicated VHF and UHF antennas. Street view on Google Maps seems to show all High gain UHF and VHF Yagis. Check out what your neighbours have as some parts of town may get better reception from Tamworth, and others from Upper Namoi.

Personally i beleive you just dont have enough signal at the aerial (cant prove this without being there obviously), and that means your amplifier is just amplify the crappy signal its getting (ie. Garbage In = Garbage Out). Oce we have some high gain antennas in, IF there still is problems we can begin to suspect things like CB Radios, Electric Fences, Cordless Phones but Ive personally had little trouble with these things.


PS. Manilla is much greener on Google maps than the last time I drove through (have family in Barraba).

Edited by nbound, 24 February 2012 - 09:44 PM.


#25 alanh

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Posted 25 February 2012 - 02:22 AM

nbound,
This antenna is about 10 element UHF (count the short elements). Also he is receiving 3 UHF stations with no problems. There is insufficient band 3 gain because of the small number of longer elements.