Juliashmoolia Posted June 30, 2008 Posted June 30, 2008 I’m hoping someone can help me with a bit of re-wiring I’m going to do. My antenna is a dick smith indoor type and the only problem with it is it is susceptible to electrical interference when I switch the light on (or when someone in my block of units does). I’ve read that interference is usually due to poor cable so I’m going to put better coaxial cable on the antenna. I’ve bought some quad shield cable from bunnings along with some screw on type f connectors. Now after reading a bit more on the forum, I notice people only using the crimp type. What is the difference between the twist on and crimp type? Should I be using the crimp type instead? I will have to go and buy a crimper if the crimp is better but I was hoping to minimise the cost if possible… Cheers -Julia
charlesc Posted June 30, 2008 Posted June 30, 2008 I’ve read that interference is usually due to poor cable so I’m going to put better coaxial cable on the antenna.Julia, you're taking a very practical approach to trying to resolve your reception difficulties. Interference (impulse noise type) is in general due to airborne transient pickup in the receiving setup. Either in the cabling from the antenna, in un-shielded connectors, splitters etc. Or directly into the antenna elements themselves. To reduce the chances of impulse interference, attention to the cabling, connectors and other components is important. Quad shielded cabling, F-connectors, metal cased splitters etc. all help. The antenna itself should be mounted away from likely sources of impulses) like the main road outside the house, electrical circuits). Externally on the roof is often a good place. The really important thing is that the antenna must be able to get the most signal it can out of the passing transmission. This will give a good quality signal (and of reasonable strength hopefully) to pass to the receiver. With a good quality signal that is well above the noise that is likely to encroach, the receiver will be able to give good reception. Indoor antennas are challenged in a number of problematic ways. They are not in the strongest part of the passing transmission signal, and so unless your are very close to the transmitters, the signal they pick up is not very good. The receive elements are right inside the house, in amongst sources of electrical disturbance. The signal echoes inside the house are short (small distances) and can make quite a mess of the received channel waveform (so there are more likely to be errors appearing). If your impulse interference problem is due to coupling through the antenna elements, changing the lead won't help. Re the connectors. Twist-on F-connectors are not well regarded. The preference would be to at least use crimp style ones. Better yet are the compression connectors (Foxtel approved method).
Juliashmoolia Posted June 30, 2008 Author Posted June 30, 2008 Julia, you're taking a very practical approach to trying to resolve your reception difficulties. Yeah... i guess i'm desperate lol. Interference (impulse noise type) is in general due to airborne transient pickup in the receiving setup. Either in the cabling from the antenna, in un-shielded connectors, splitters etc. Or directly into the antenna elements themselves.To reduce the chances of impulse interference, attention to the cabling, connectors and other components is important. Quad shielded cabling, F-connectors, metal cased splitters etc. all help. The antenna itself should be mounted away from likely sources of impulses) like the main road outside the house, electrical circuits). Externally on the roof is often a good place. Well I guess this is the first of my problems. My antenna in an indoors one, and only has about a meter of cable attached, meaning the only place I can put it is on top of the TV, which incidentally is right next to a light switch. I’m hoping by upgrading to quad shield, I’ll perhaps minimise this interference and also allow me to make the cable longer so I can put the antenna on my bookshelf which is higher up and also away from the light switch. The really important thing is that the antenna must be able to get the most signal it can out of the passing transmission. This will give a good quality signal (and of reasonable strength hopefully) to pass to the receiver. With a good quality signal that is well above the noise that is likely to encroach, the receiver will be able to give good reception. Indoor antennas are challenged in a number of problematic ways. They are not in the strongest part of the passing transmission signal, and so unless your are very close to the transmitters, the signal they pick up is not very good. The receive elements are right inside the house, in amongst sources of electrical disturbance. The signal echoes inside the house are short (small distances) and can make quite a mess of the received channel waveform (so there are more likely to be errors appearing). I live in Adelaide at Henley Beach and can see the towers on Mt Lofty from my window, so I wouldn’t say I was in a bad reception area. However I do live fairly close to Adelaide Airport (its 5 kms from my house) and although I’m not in the direct flight path, I do occasionally get smaller aeroplanes circling around, and I have a feeling this may cause some of the longer drop outs I get where the whole picture just goes crazy for about 30 seconds, then returns to normal. If your impulse interference problem is due to coupling through the antenna elements, changing the lead won't help. What is coupling through the antenna elements? Does this mean two of the inside wires are touching or something? Re the connectors. Twist-on F-connectors are not well regarded. The preference would be to at least use crimp style ones. Better yet are the compression connectors (Foxtel approved method). Ok I’ll get crimp ones. Even if all of this rigmarole does nothing to improve my signal, at least i know there is nothing i can do about it and that will at least make me feel slightly better than if i hadn't done anything to try to fix it. Thanks for your help Charlesc
charlesc Posted June 30, 2008 Posted June 30, 2008 I live in Adelaide at Henley Beach and can see the towers on Mt Lofty from my window..Do you know the channel numbers that you receive from there? Are most on VHF (like digital CH6, 8, 11, 12)? Or are they on higher numbers, UHF? The VHF ones will be received by the rabbit's ears part of your antenna, the UHF frequencies by the smaller horizontal elements.However I do live fairly close to Adelaide Airport ...and I have a feeling this may cause some of the longer drop outs I get ...DVB-T is not very good at handling doppler effect echoes from moving objects (as opposed to multipath echoes, which it handles very well).What is coupling through the antenna elements? Does this mean two of the inside wires are touching or something?What I meant was the method by which the passing radio waves 'couple' into the antenna itself. If you hold a piece of wire up, the passing radio waves will electromagnetically 'link' into the wire. When that wire is an antenna, and has a connection point to it, you will 'receive' a signal from the antenna. The stronger the radio waves passing the antenna, the more signal you get. Even if all of this rigmarole does nothing to improve my signal, at least i know there is nothing i can do about it and that will at least make me feel slightly better than if i hadn't done anything to try to fix it......and also allow me to make the cable longer so I can put the antenna on my bookshelf which is higher up and also away from the light switch.. Good approach. You might find the thin cable from the antenna is tricky to fit to a standard crimp. You might need the smaller RG-59 size.One approach you could try is to just take the indoor antenna to a TV shop and see if they will crimp you on a decent length of RG-6 quad shield, with the right connectors that you need.
charlesc Posted June 30, 2008 Posted June 30, 2008 I live in Adelaide at Henley Beach and can see the towers on Mt Lofty from my window Is MT Lofty the same as:- Transmitter Location - ntl Tower Summit Road CRAFERS This was from the ABC link http://www.abc.net.au/reception/.
mtv Posted June 30, 2008 Posted June 30, 2008 Is MT Lofty the same as:-Transmitter Location - ntl Tower Summit Road CRAFERS Yep.... the same
charlesc Posted June 30, 2008 Posted June 30, 2008 Yep.... the same Thanks mtv. So Julia you are probably receiving the main channels on VHF, and SBS via it's UHF frequency ( CH33 564.5 MHz).
Juliashmoolia Posted June 30, 2008 Author Posted June 30, 2008 Do you know the channel numbers that you receive from there? Are most on VHF (like digital CH6, 8, 11, 12)? Or are they on higher numbers, UHF? The VHF ones will be received by the rabbit's ears part of your antenna, the UHF frequencies by the smaller horizontal elements. To be honest i'm not quite sure. I'll have to check tonight. I know that moving the actual rabbit ears part is what affects the reception the most so i'd say they are probably VHF. Good approach. You might find the thin cable from the antenna is tricky to fit to a standard crimp. You might need the smaller RG-59 size.One approach you could try is to just take the indoor antenna to a TV shop and see if they will crimp you on a decent length of RG-6 quad shield, with the right connectors that you need. Actually i've removed the old thin wire altogether and soldered new quad cable directly to the circuit board thing. I haven't actually tested it yet with the new cable and won't until i can get the right crimped connections attached, but i'll let you know if it works...
Juliashmoolia Posted June 30, 2008 Author Posted June 30, 2008 Thanks mtv.So Julia you are probably receiving the main channels on VHF, and SBS via it's UHF frequency ( CH33 564.5 MHz). Yep i think this is the case.
charlesc Posted June 30, 2008 Posted June 30, 2008 Actually i've removed the old thin wire altogether and soldered new quad cable directly to the circuit board thing. Even better....
Juliashmoolia Posted July 1, 2008 Author Posted July 1, 2008 Even better.... I soldered the new coaxial cable to the antenna last night but it broke off straight away becuase the coaxial is too stiff and inflexible. so i've soldered some flexible wire to the coaxial cable then soldered that to the antenna circuit board and that holds much better. i tested it last night and it works fine but i still get interference from light switches. i attached the twist on f connectors and i think if i replace these with the clamp type it might help a bit more. thanks for ya help charlesc
alanh Posted July 1, 2008 Posted July 1, 2008 Julia, Where in Adelaide are you. Your problem is insufficient TV signal. There are a number of UHF translators in Adelaide. If you were to remove the rabbits ears and use only UHF you would be better off if you are in a coverage area. Read Get the Best Reception, Adelaide and read the links. If the SA link does not work, the administrator is removing attached files. I wll paste new ones at the weekend. AlanH
mtv Posted July 1, 2008 Posted July 1, 2008 Julia,Where in Adelaide are you. AlanH I live in Adelaide at Henley Beach and can see the towers on Mt Lofty from my window
Theres Always Radio Posted July 1, 2008 Posted July 1, 2008 My strong view is that those who use indoor antennas should not be permitted to complain about anything! Cheers James
charlesc Posted July 1, 2008 Posted July 1, 2008 My strong view is that those who use indoor antennas should not be permitted to complain about anything! Heartfelt from the transmission side of the tracks. Probably true enough in many ways. Challenges are always interesting though.
wahroonga farm Posted July 1, 2008 Posted July 1, 2008 My strong view is that those who use indoor antennas should not be permitted to complain about anything!Cheers James That's got my vote, but when the OP has a catchy pen name .....
Juliashmoolia Posted July 2, 2008 Author Posted July 2, 2008 Julia,Where in Adelaide are you. Henley Beach Your problem is insufficient TV signal. There are a number of UHF translators in Adelaide. If you were to remove the rabbits ears and use only UHF you would be better off if you are in a coverage area. I will try removing the rabbit ears tonight and see if this improves the signal. Read Get the Best Reception, Adelaide and read the links.If the SA link does not work, the administrator is removing attached files. I wll paste new ones at the weekend. AlanH I have tried going through these steps but I honestly cannot work out how to interperate those tables etc. They are too complex for me to understand - I guess i'm in over my head.
Juliashmoolia Posted July 2, 2008 Author Posted July 2, 2008 (edited) My strong view is that those who use indoor antennas should not be permitted to complain about anything!Cheers James Yes i know but i rent my unit and if i install a TV antenna, the rules are i can't take it with me when i move. I installed one at my previous unit which i also rented and i had to leave it behind and don't want to outlay any more money than i already have. Plus i'm in a block of flats and there is a person above me, so even if i didn't mind leaving it when i move, i would have to install it outside and that requires the strata group approval etc, which would be a hassle my landlord would not want to deal with. (I fear he would think it easier to up the rent and 'force' me out than deal with those type of hassels.) Ugh i wish there was some law obligated landlords to put up a decent tv antenna. Never mind, its not like i have absolutely terrible recepiton. It is bearable Edited July 2, 2008 by Juliashmoolia
Juliashmoolia Posted July 2, 2008 Author Posted July 2, 2008 What if i buy one of these antennas instead? Winegard SS-3000 Would that be better than my current one do you think?
mtv Posted July 2, 2008 Posted July 2, 2008 Julia, Which DSE antenna do you have?(Cat number?).... the link in your first post only goes to the main page. There's no guarantee any other indoor antenna will work better than what you already have. When you say you can see the towers on Mt Lofty from your window, if you place the antenna near the window, it will have the best possible chance of receiving the signals. Are you on the ground floor, or higher? If higher, do you have a balcony? I have had great success previously with Fracarro LP34/5HV antennas used in situations like yours. Although they are an outdoor antenna, they are small enough to be clamped on a balcony rail or other temporary mount. I have even put them in a pot (for a pot plant) with a garden stake as a short mast, both outside on the ground and on balconies.... so it doesn't become a 'fixture' of the building and therefore, landlords/agents have no claim for it to be left when you vacate. Given the fact you have line of sight to the transmitters, one of these will work far better than any indoor-type antenna.
digitalj Posted July 2, 2008 Posted July 2, 2008 (edited) mtv, looking at the end of the URL it is cat. no. L4017 Here's a direct link in the meantime (till about midnight) http://www.dse.com.au/cgi-bin/dse.storefro...duct/View/L4017 Edited July 2, 2008 by digitalj
mtv Posted July 2, 2008 Posted July 2, 2008 Thanks digitalj As suspected, that antenna has very poor directional characteristics for VHF (all channels except SBS, which uses the smaller directional part of the antenna). As per my previous post, the Fracarro LP34/5HV (or similar antenna) will provide far superior performance.
Juliashmoolia Posted July 2, 2008 Author Posted July 2, 2008 Julia,Which DSE antenna do you have?(Cat number?).... the link in your first post only goes to the main page. The catalogue number is L4017. Wierd how smiths dick site does that huh... There's no guarantee any other indoor antenna will work better than what you already have.When you say you can see the towers on Mt Lofty from your window, if you place the antenna near the window, it will have the best possible chance of receiving the signals. I have done so and I do get better reception, however I still get interference from light switches and other sources that I can't pinpoint, but I’m assuming is either neighbours electrical devices or aircraft. Are you on the ground floor, or higher? If higher, do you have a balcony?I have had great success previously with Fracarro LP34/5HV antennas used in situations like yours. Although they are an outdoor antenna, they are small enough to be clamped on a balcony rail or other temporary mount. I am on the ground floor so no balcony. There is person above me. I have even put them in a pot (for a pot plant) with a garden stake as a short mast, both outside on the ground and on balconies.... so it doesn't become a 'fixture' of the building and therefore, landlords/agents have no claim for it to be left when you vacate. Given the fact you have line of sight to the transmitters, one of these will work far better than any indoor-type antenna. Hmmm this is an option. I have a couple of spots I put one but I think the problem would be getting the cable inside somehow. That said, I just remembered there some holes up the top of each room (the ones installed when the building is built, you know for air circulation) which I reckon I might be able to squeeze a cable through. This is a possibility I will investigate tonight. The place i'm thinking is on top of my shed outside, but that building complex is blocking the line of sight, will this be a problem? I would have to run a lot of cable, 10 meters i reckon, is that too far? Otherwise, this site suggets putting a RF filter on the TV power cable to reduce interference.... Do you think that could work? -j
mtv Posted July 2, 2008 Posted July 2, 2008 (edited) A filter on the mains will only help if the interference is coming through the mains power and not entering the tuner via the antenna and/or coax. You could try a ferrite clamp-on suppressor (eg: Jaycar) on both the power cable to the screen/tuner and also the antenna coax... but once again, it's just adding to the cost. What you need is a better signal to noise ratio.... which basically means increasing the received signal level, so that it's much greater than the interference level. By having a directional antenna outside will help considerably. 10 metres of RG6 Quadshield will be fine. If it's not possible to place an antenna outside, you could place a Fracarro antenna inside at the window. It seems to me that you are throwing money away experimenting with bandaid fixes for an indoor antenna which is unlikely to provide reliable performance. Edited July 2, 2008 by mtv
charlesc Posted July 2, 2008 Posted July 2, 2008 The place i'm thinking is on top of my shed outside, but that building complex is blocking the line of sight, will this be a problem? You can but try. It would probably be better than indoors. And for the lower VHF frequencies, you may not notice it as much, so it might be OK. I would have to run a lot of cable, 10 meters i reckon, is that too far? Try and use good quality RG6 quad shielded. It'll probably be OK. The compact Fracarro LPxxx antennas would pickup a reasonable signal, certainly compared to an indoor unit. Otherwise, ...suggets putting a RF filter on the TV power cable to reduce interference.... Do you think that could work? Unlikely, especially if the transient is coming in via the antenna itself, through the air. This thread is quite topical. I'm actually doing some tests on a range of generally available indoor antennas, and comparing them both amongst themselves, and to a few of the compact Fracarro units. Like mtv said, the small log periodics are invariably the better choice if you can squeeze them in somewhere. Compact Fracarro LPxxx LP345MHV 15 element 0.72m long LPV345HV 9 element 0.71m long (popular for caravans) LP345HV 16 element 1.11m (normal full size metro antenna, shown for comparison)
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