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#1 AVRON

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Posted 05 August 2011 - 10:07 AM

I had an exisiting mast up with two antennas, a large one pointed toward a Sydney transmitter and above that, a small one pointed toward Wollongong. It operated fine for about two years and then the power supply for the mast amplifier died.

The installer replaced the mast amplifier with a Kingray (looks to be a MHW34FS), hooked both antennas up and confirmed all signals were good and left. Problem is all the ABC channels were strong but the channels would be broken up. I asked him to come fix, he tried, couldn't diagnose it and eventually suggested I disconnect one antenna. The problem is, despite the signal strengths, a few of those channels still are very unstable (channel 11).

Can someone tell me how I can revert back to the same antenna configuration I had before, using both antennas, without having any problem with the two antennas both picking up the ABC channels from the same sydney transmitter?

#2 debruis

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Posted 05 August 2011 - 11:10 AM

I had an exisiting mast up with two antennas, a large one pointed toward a Sydney transmitter and above that, a small one pointed toward Wollongong. It operated fine for about two years and then the power supply for the mast amplifier died.

The installer replaced the mast amplifier with a Kingray (looks to be a MHW34FS), hooked both antennas up and confirmed all signals were good and left. Problem is all the ABC channels were strong but the channels would be broken up. I asked him to come fix, he tried, couldn't diagnose it and eventually suggested I disconnect one antenna. The problem is, despite the signal strengths, a few of those channels still are very unstable (channel 11).

Can someone tell me how I can revert back to the same antenna configuration I had before, using both antennas, without having any problem with the two antennas both picking up the ABC channels from the same sydney transmitter?


I would replace Masthead Amplifier with MHU-34 (amplify UHF only) if South Coast reception is OK. I believe the problem is too much incoming signal on the Sydney channels. This would be causing low SNR and high BER. The installer probably could not diagnose the problem as his meter could not read SNR or BER only the DCP. Sound like another "Put up the antenna where we can find the highest signal level and she'll be right mate". ABC ,Seven,Nine & Ten can be very sensitive to any type of amplification and to adjust and calibrate require a meter with the functions and reading that I have mentioned above.

#3 mtv

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Posted 05 August 2011 - 11:32 AM

I had an exisiting mast up with two antennas, a large one pointed toward a Sydney transmitter and above that, a small one pointed toward Wollongong. It operated fine for about two years and then the power supply for the mast amplifier died.

The installer replaced the mast amplifier with a Kingray (looks to be a MHW34FS), hooked both antennas up and confirmed all signals were good and left. Problem is all the ABC channels were strong but the channels would be broken up. I asked him to come fix, he tried, couldn't diagnose it and eventually suggested I disconnect one antenna. The problem is, despite the signal strengths, a few of those channels still are very unstable (channel 11).

Can someone tell me how I can revert back to the same antenna configuration I had before, using both antennas, without having any problem with the two antennas both picking up the ABC channels from the same sydney transmitter?


Do you get ABC channels from both Sydney and Wollongong?

If only Wollongong, it's possible your tuner, when scanning, is only locking in the Wollongong ABC, so you could try deleting the stored ABC channels and manually entering the Sydney ABC frequency which is 226.500 MHz.

Condiering it all used to work fine previously before the amp/powersupply died, replacing the amp/supply and adjusting it correctly should have solved your problem, unless there is still something else in your cabling etc which may have caused the fault with the amp/supply in the first place. eg: short circuit in cabling or connections.

The thing of concern is that the installer couldn't diagnose the problem.

What equipment did he use? What tests did he perform? What knowledge and experience does he have? (I'm guessing you won't know the answers to those questions, but these things are important for an installer).

Are you saying that you have now disconnected one antenna, but still have the problem?

An amplifier will increase the signal strength, but generally not increase the signal quality, which determines reception reliability.

It's possible the installer has not set the amp up correctly, with signal levels on some channels possibly being too strong, causing overload.

Is your Sydney antenna specifically designed for only channels 6 & above?

If it's designed to receive lower channels (eg: ABC Ch2 analogue) very strong analogue channels may be causing interference, especially if the amp has not been adjusted correctly.

Where are you located?

Check the frequency of the ABC channels you are receiving and post the figures so we'll know which ones you are receiving. Sydney should be 226.500 MHz and Wollongong (Knights Hill) should be 690.500 MHz.

It's difficult to determine the problem is without being there, inspecting, testing and obtaining accurate signal measurements.

#4 charlesc

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Posted 05 August 2011 - 02:30 PM

I had an exisiting mast up with two antennas, a large one pointed toward a Sydney transmitter and above that, a small one pointed toward Wollongong.

In case it helps you better identify your signal sources for mtv and debruis, the detail below shows what the various transmitters may be sending towards you.

I'm guessing you may have a fairly typical Sydney/Knights Hill eastern coast antenna setup. A separate VHF antenna to the main Sydney transmitters, and a smaller UHF one to the Knights Hill transmitter.
So you'd receive 6,8,11,12 (SEVEN, NINE, TEN, ABC) from Sydney, and then all channels from the Illawarra (36, 37, 38, 51, 54 (WIN, SC10, PRIME, ABC, SBS).

This is fairly typical because if you try and get SBS from Sydney as well on CH34, that is very close to the lowest Knights Hill channel on CH36. It would not be easy to keep the antennas signals separate (wanted 36, unwanted 34), and combining those antennas would most likely lead to problems with SBS. The system would have the main signal from Sydney on 34, and the smaller UHF antenna would add in another CH34 picked up from the side or rear. These reflections/delays are likely to cause problems, as SBS is part of a wide area Single Frequency Network (SFN).
Better to have VHF only on one amplifier input, and UHF on the other. And in the above case, source SBS from Knights Hill, depending on errors in CH34.

The reasons for your ABC problems I think mtv and debruis have covered. It sounds like the installer didn't take all the readings that he should have. In particular once an amplifier is in the system, all signals coming into it need to be known about, measured and allowed for.

A Sydney antenna that doesn't go below CH6 would be desirable.

Can you identify where you are, and could you maybe post a picture of your antenna setup?



These are the channels from the main transmitters on the North Shore.
ABC VHF 12 Hor 226.5 MHz ABC Tower 221 Pacific Highway GORE HILL
SEVEN VHF 6 Hor 177.5 MHz Ch7/10 Tower 192-196 Hampden Road ARTARMON
NINE VHF 8 Hor 191.625 MHz TCN 9 Television Tower Artarmon Road WILLOUGHBY
TEN VHF 11 Hor 219.5 MHz Ch7/10 Tower 192-196 Hampden Road ARTARMON
SBS UHF 34 Hor 571.5 MHz ABC Tower 221 Pacific Highway GORE HILL
TVS UHF 29 Hor 536.625 MHz ABC Tower 221 Pacific Highway GORE HILL


And those at Kings Cross.
ABC UHF 30 Hor 543.625 MHz Elan Building Victoria St KINGS CROSS
SEVEN UHF 48 Hor 669.5 MHz Elan Building Victoria St KINGS CROSS
NINE UHF 33 Hor 564.5 MHz Elan Building Victoria St KINGS CROSS
TEN UHF 45 Hor 648.5 MHz Elan Building Victoria St KINGS CROSS
SBS UHF 34 Hor 571.5 MHz Elan Building Victoria St KINGS CROSS



And those at North Head.
ABC UHF 30 Hor 543.625 MHz Broadcast Site Sewage Treatment Plant MANLY
SEVEN UHF 48 Hor 669.5 MHz Broadcast Site Sewage Treatment Plant MANLY
NINE UHF 33 Hor 564.5 MHz Broadcast Site Sewage Treatment Plant MANLY
TEN UHF 45 Hor 648.5 MHz Broadcast Site Sewage Treatment Plant MANLY
SBS UHF 34 Hor 571.5 MHz Broadcast Site Sewage Treatment Plant MANLY



These are the channels from the main transmitter in theIllawarra.

Knights Hill
WIN UHF 36 Hor 585.5 MHz New WIN Tower, KNIGHTS HILL
STHN CROSS UHF 37 Hor 592.5 MHz New WIN Tower, KNIGHTS HILL
PRIME UHF 38 Hor 599.5 MHz New WIN Tower, KNIGHTS HILL
ABC UHF 51 Hor 690.5 MHz Broadcast Australia Digital Television Tower KNIGHTS HILL
SBS UHF 54 711.625 MHz Broadcast Australia Digital Television Tower KNIGHTS HILL


EDIT: added some detail

Edited by charlesc, 05 August 2011 - 04:27 PM.


#5 AVRON

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Posted 06 August 2011 - 07:33 PM

Thanks for the suggestions.

I have checked the mast amplifier (a Kingray MHW34F) and noticed a jumper called COMB. Is that to combine two antenna? If so, it's not bridged and may be why when both antenna are connected the ABC channels break up.

Both gain pots are turned full up, so I suspect that is over catering for what should be pretty average reception here in Westleigh (near Hornsby).

I'll try post an image tomorrow, but the large antenna is the one pointing to Sydnet and the smaller one above that is pointing towards Wollongong direction and is currently disconnected.

Thanks,
Avron


In case it helps you better identify your signal sources for mtv and debruis, the detail below shows what the various transmitters may be sending towards you.

I'm guessing you may have a fairly typical Sydney/Knights Hill eastern coast antenna setup. A separate VHF antenna to the main Sydney transmitters, and a smaller UHF one to the Knights Hill transmitter.
So you'd receive 6,8,11,12 (SEVEN, NINE, TEN, ABC) from Sydney, and then all channels from the Illawarra (36, 37, 38, 51, 54 (WIN, SC10, PRIME, ABC, SBS).

This is fairly typical because if you try and get SBS from Sydney as well on CH34, that is very close to the lowest Knights Hill channel on CH36. It would not be easy to keep the antennas signals separate (wanted 36, unwanted 34), and combining those antennas would most likely lead to problems with SBS. The system would have the main signal from Sydney on 34, and the smaller UHF antenna would add in another CH34 picked up from the side or rear. These reflections/delays are likely to cause problems, as SBS is part of a wide area Single Frequency Network (SFN).
Better to have VHF only on one amplifier input, and UHF on the other. And in the above case, source SBS from Knights Hill, depending on errors in CH34.

The reasons for your ABC problems I think mtv and debruis have covered. It sounds like the installer didn't take all the readings that he should have. In particular once an amplifier is in the system, all signals coming into it need to be known about, measured and allowed for.

A Sydney antenna that doesn't go below CH6 would be desirable.

Can you identify where you are, and could you maybe post a picture of your antenna setup?



These are the channels from the main transmitters on the North Shore.
ABC VHF 12 Hor 226.5 MHz ABC Tower 221 Pacific Highway GORE HILL
SEVEN VHF 6 Hor 177.5 MHz Ch7/10 Tower 192-196 Hampden Road ARTARMON
NINE VHF 8 Hor 191.625 MHz TCN 9 Television Tower Artarmon Road WILLOUGHBY
TEN VHF 11 Hor 219.5 MHz Ch7/10 Tower 192-196 Hampden Road ARTARMON
SBS UHF 34 Hor 571.5 MHz ABC Tower 221 Pacific Highway GORE HILL
TVS UHF 29 Hor 536.625 MHz ABC Tower 221 Pacific Highway GORE HILL


And those at Kings Cross.
ABC UHF 30 Hor 543.625 MHz Elan Building Victoria St KINGS CROSS
SEVEN UHF 48 Hor 669.5 MHz Elan Building Victoria St KINGS CROSS
NINE UHF 33 Hor 564.5 MHz Elan Building Victoria St KINGS CROSS
TEN UHF 45 Hor 648.5 MHz Elan Building Victoria St KINGS CROSS
SBS UHF 34 Hor 571.5 MHz Elan Building Victoria St KINGS CROSS



And those at North Head.
ABC UHF 30 Hor 543.625 MHz Broadcast Site Sewage Treatment Plant MANLY
SEVEN UHF 48 Hor 669.5 MHz Broadcast Site Sewage Treatment Plant MANLY
NINE UHF 33 Hor 564.5 MHz Broadcast Site Sewage Treatment Plant MANLY
TEN UHF 45 Hor 648.5 MHz Broadcast Site Sewage Treatment Plant MANLY
SBS UHF 34 Hor 571.5 MHz Broadcast Site Sewage Treatment Plant MANLY



These are the channels from the main transmitter in theIllawarra.

Knights Hill
WIN UHF 36 Hor 585.5 MHz New WIN Tower, KNIGHTS HILL
STHN CROSS UHF 37 Hor 592.5 MHz New WIN Tower, KNIGHTS HILL
PRIME UHF 38 Hor 599.5 MHz New WIN Tower, KNIGHTS HILL
ABC UHF 51 Hor 690.5 MHz Broadcast Australia Digital Television Tower KNIGHTS HILL
SBS UHF 54 711.625 MHz Broadcast Australia Digital Television Tower KNIGHTS HILL


EDIT: added some detail



#6 Tazzy2Heads

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Posted 06 August 2011 - 09:56 PM

Thanks for the suggestions.

I have checked the mast amplifier (a Kingray MHW34F) and noticed a jumper called COMB. Is that to combine two antenna? If so, it's not bridged and may be why when both antenna are connected the ABC channels break up.

Both gain pots are turned full up, so I suspect that is over catering for what should be pretty average reception here in Westleigh (near Hornsby).

I'll try post an image tomorrow, but the large antenna is the one pointing to Sydnet and the smaller one above that is pointing towards Wollongong direction and is currently disconnected.

Thanks,
Avron


Hi Avron,
The AMP is set up correctly for two separate antennas if the combining link is NOT BRIDGED, or one of either VHF or UHF in the right connections. It is
bridged when using a COMBINATION ANTENNA for VHF and UHF signals from the one antenna.
I used to live in that area many moons ago and would have thought you would NOT get signals from Wollongong in Westleigh , only the Sydney main towers , but it all may have changed since Digital kicked in.If the UHF antenna is not connected now I would think you are missing out on SBS 34 and
CH 31 from the main Sydney towers .If the antennas are old they may be not picking up the new Digital channels as good as what there is there to get.
The VHF one won't be designed for Digital ABC CH12 and the UHF one could be designed for the Anologue ONLY CH 28.
If every thing was working ok up until the Amp power pack was replaced and it is the correct replacement,it maybe worth checking the simple things
first, the flyleads and wallplate and its connections as they would have been unplugged and replugged to fit the new power injector.
Anyway if you can get a photo of the antennas up the local guys will be able to give you more help , but you really need someone with a good Digital
meter that can measure BER/MER to sort it all out for you.Hope that helps a bit. Tazzy.

#7 debruis

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Posted 07 August 2011 - 10:01 AM

Thanks for the suggestions.

I have checked the mast amplifier (a Kingray MHW34F) and noticed a jumper called COMB. Is that to combine two antenna? If so, it's not bridged and may be why when both antenna are connected the ABC channels break up.

Both gain pots are turned full up, so I suspect that is over catering for what should be pretty average reception here in Westleigh (near Hornsby).

I'll try post an image tomorrow, but the large antenna is the one pointing to Sydnet and the smaller one above that is pointing towards Wollongong direction and is currently disconnected.

Thanks,
Avron


It would be high unlikely any Masthead amplifier would be required for Sydney Channels where you are located. I did a job for forum member diesel who lives in that general area and his antenna did not need mast head amplification and he had 4 outlets.
I have also found that for reliable reception of ABC VHF 12 the height of the antenna is critical for good SNR/BER (reliable reception). Movement up or down 600mm to 1000mm can make all the difference.
South Coast(Knights Hill) ABC can also be tricky once again it is very height dependent. I find the lower the better as it minimize the possibility of inteference from the Newcastle Transmitter(Mt Sugarloaf that uses the same frequencies as the South Coast. Also it is highly likely that the ABC from the South Coast is being overdriven having the pots up full. If the antenna is in the correct position then generally South Coast channel only need minimal amplification and usually only too compensate for multiple outlets.

#8 mtv

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Posted 07 August 2011 - 01:24 PM

I'd certainly agree that you probably have an overloading situation with that level of amplification, especially the Sydney channels.

Can you post some pics of the antennas you are using?

If you have an antenna designed to receive channels below channel 6, ABC Ch2 analogue will almost certainly be causing overloading of your digital tuner and even the digital channels are probably way too high.

Given your installer couldn't even diagnose the problem, I think you should find another installer with the necessary equipment, experience and knowledge to solve the issue.

It's not DIY solution.

#9 Tazzy2Heads

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Posted 07 August 2011 - 02:16 PM

I'd certainly agree that you probably have an overloading situation with that level of amplification, especially the Sydney channels.

Can you post some pics of the antennas you are using?

If you have an antenna designed to receive channels below channel 6, ABC Ch2 analogue will almost certainly be causing overloading of your digital tuner and even the digital channels are probably way too high.

Given your installer couldn't even diagnose the problem, I think you should find another installer with the necessary equipment, experience and knowledge to solve the issue.

It's not DIY solution.


Hi Guy's,
Local Knowledge wins again ! I am once again wr.. wro.. incorrect, I woulld have almost put money on the Illawarra UHF signals being yery hard to get at
Westleigh with them being blocked by trees and buildings etc , but when you think about it a high gain antenna on the roof of a double story McMansion is
a fair way up and so is Knigts Hill.We used to watch vhf WIN tv in the summertime when ducting was happening up and down the coast.
SORRY for the interuption , I'M STILL LEARNING , I will go back to the lounge chair and sit back and learn some more .cheers Tazzy.

#10 AVRON

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Posted 08 August 2011 - 04:54 PM

okay, here's the pic of the antenna setup, which worked a treat prior to the amp power supply failing.

Antenna image

I presume that I could start with only one antenna connected to the amp at a time and lowest gain setting to see what channels can be received and how stable. If I do this with both antenna and then attach both to the amp, will I expect issues with ABC signals affecting each other from both antenna (where the VHF may receive the strong ABc channels incidentally)?

I used a Jim's Antenna guy and he cam back to try fix only to seem complete confused, so am loathe to try get them to sort it out any further, so may try my hand at a bit of "fixing" myself, if possible.

Thanks,
Avron


I'd certainly agree that you probably have an overloading situation with that level of amplification, especially the Sydney channels.

Can you post some pics of the antennas you are using?

If you have an antenna designed to receive channels below channel 6, ABC Ch2 analogue will almost certainly be causing overloading of your digital tuner and even the digital channels are probably way too high.

Given your installer couldn't even diagnose the problem, I think you should find another installer with the necessary equipment, experience and knowledge to solve the issue.

It's not DIY solution.


Edited by AVRON, 08 August 2011 - 04:56 PM.


#11 Tazzy2Heads

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Posted 08 August 2011 - 06:14 PM

okay, here's the pic of the antenna setup, which worked a treat prior to the amp power supply failing.

Antenna image

I presume that I could start with only one antenna connected to the amp at a time and lowest gain setting to see what channels can be received and how stable. If I do this with both antenna and then attach both to the amp, will I expect issues with ABC signals affecting each other from both antenna (where the VHF may receive the strong ABc channels incidentally)?

I used a Jim's Antenna guy and he cam back to try fix only to seem complete confused, so am loathe to try get them to sort it out any further, so may try my hand at a bit of "fixing" myself, if possible.

Thanks,
Avron


Hi Avron,
Yes you can connect one antenna at a time but you will have to put back the combining LINK when you connect the big combination antenna for the SYDNEY channels and it would pay you as you said to start with the gain for UHF and VHF set to minimum . I think it may pay you to do a factory default reset to clear any Wollongong channel settings at this stage.If everything is ok then you shouldn't need the Wollongong antenna unless I'm missing something, ( it's been over 20 years since I worked in that area and there has certainly been some changes since then) if you need the WOLLONGONG antenna for some or all of the UHF channels you can put the UHF antenna into the UHF connection then take OFF the combining link and go back to two separate antennas, with that set up you will get the SYDNEY VHF channels only from the big antenna and the WOLLONGONG UHF channels from the UHF
antenna and you may have to do another factory reset to clear the SYDNEY UHF channel settings from the memory as these will be cut out once you take off the combining link for the separate antenna senario.So when you retune you should get with the big antenna still connected the VHF channels from SYDNEY and the UHF channels from WOLLONGONG if you still need them. I guess there was a reason why the uhf antenna was put up in the first place
so there may be some problem with the Sydney signals at that location.
The trick is do one step at a time and make sure you are tuned to the right channels for the antenna you have connected at the time and don't worry about duplicate channels from Sydney or Wollongong as they should be on different bands and the tuner will sort that out , then you can delete the ones you don't want if it creates a funny channel listing sequence problem, and do the gain adjustment in stages, you probably won't want much gain on VHF.
Go carefully Tazzie.

#12 Tazzy2Heads

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Posted 08 August 2011 - 07:48 PM

Hi Avron,
Yes you can connect one antenna at a time but you will have to put back the combining LINK when you connect the big combination antenna for the SYDNEY channels and it would pay you as you said to start with the gain for UHF and VHF set to minimum . I think it may pay you to do a factory default reset to clear any Wollongong channel settings at this stage.If everything is ok then you shouldn't need the Wollongong antenna unless I'm missing something, ( it's been over 20 years since I worked in that area and there has certainly been some changes since then) if you need the WOLLONGONG antenna for some or all of the UHF channels you can put the UHF antenna into the UHF connection then take OFF the combining link and go back to two separate antennas, with that set up you will get the SYDNEY VHF channels only from the big antenna and the WOLLONGONG UHF channels from the UHF
antenna and you may have to do another factory reset to clear the SYDNEY UHF channel settings from the memory as these will be cut out once you take off the combining link for the separate antenna senario.So when you retune you should get with the big antenna still connected the VHF channels from SYDNEY and the UHF channels from WOLLONGONG if you still need them. I guess there was a reason why the uhf antenna was put up in the first place
so there may be some problem with the Sydney signals at that location.
The trick is do one step at a time and make sure you are tuned to the right channels for the antenna you have connected at the time and don't worry about duplicate channels from Sydney or Wollongong as they should be on different bands and the tuner will sort that out , then you can delete the ones you don't want if it creates a funny channel listing sequence problem, and do the gain adjustment in stages, you probably won't want much gain on VHF.
Go carefully Tazzie.


Sorry I forgot to ask where is the amplifier ? I can't see it in the photo's , can you be sure the right cables are in the right connections on the amp.As was said in an earlier post you may not need one at all, or may be only for the Wollongong channels if there is more than one outlet,Anyway the the antennas are a long way up and the combination one is looking for trouble being a Bands 1,2?,3 and 4 Anologue type as previosly said.If you can't get things back to how they were before the power pack went RS your only solution is the man with the meter and the knowledge to see whether he can make it work as is or update the lot . Good luck Tazzy

#13 debruis

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Posted 08 August 2011 - 09:55 PM

Hi Guy's,
Local Knowledge wins again ! I am once again wr.. wro.. incorrect, I woulld have almost put money on the Illawarra UHF signals being yery hard to get at
Westleigh with them being blocked by trees and buildings etc , but when you think about it a high gain antenna on the roof of a double story McMansion is
a fair way up and so is Knigts Hill.We used to watch vhf WIN tv in the summertime when ducting was happening up and down the coast.
SORRY for the interuption , I'M STILL LEARNING , I will go back to the lounge chair and sit back and learn some more .cheers Tazzy.


Knights Hill would not be too difficult to pick up at Westleigh. I have done installations in valleys in Hornsby and St Ives which are quite close by to Westleigh and would be about the same distance away from the tower that are receiving all channels. The Knights Hill signal is very robust at a long distance. Signal also seem to have a better BER at a lower antenna height. Antenna I normally use is a EE-06

#14 AVRON

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Posted 09 August 2011 - 05:10 PM

Thanks for all your feedback. I managed to have a look at the connections on the masthead amp, which is actually at the bottom of the very tall mast, and found the installer had switched the connections. So the VHF combo antenna was connected to the amp's UHF/VHF line and the UHF was connected to the VHF line.

Once I switched those two round, turned down the gain on both almost to the lowest, I can now get around 52 channels, most duplicates, but now from Syndey and Illawarra transmitters.

Once again, thanks for your advice and ideas, they were all much appreciated and very helpful.

Thanks,
Avron


Knights Hill would not be too difficult to pick up at Westleigh. I have done installations in valleys in Hornsby and St Ives which are quite close by to Westleigh and would be about the same distance away from the tower that are receiving all channels. The Knights Hill signal is very robust at a long distance. Signal also seem to have a better BER at a lower antenna height. Antenna I normally use is a EE-06