HDTV, Digital TV and antenna discussion thread [consolidated]

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jayz_sg

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@jayz_sg

Ok, now the picture is clearer for us to talk about using using mixer.

We will need a bi-directional splitter/mixer, available from amazon, that looks like this to combine the two signal sources (actually I believe a normal 2 way splitter will work just as well):
81mcBb1IJuL._AA1500_.jpg

From soundtech you feed the fta digital channels (hd5, dig5, dig 8 and digCNA) on Channels 29 and 38, plus very poor analogue signals, and 15 mysterious scrambled channels - the frequencis of which are unknown - to one input of the mixer.

The other input will come from the scv outlet which comprises the fta analogue channels, some of which have been shifted to different frequencies (CNA, U and octo), plus tv1, one free sports channel on 76.25 Mhz, and many starhub scrambled channels.
The question is whether starhub use Channels 29 and 38. If they don't then you will get clean output for these two channels from the mixer. The other question is whether the 15 unknown channels from sountech will clash with the fta analogue channels from scv output, when the two sources are combined.

I think the poor analogue signals from the soundtech will not be an issue.

Perhaps a kind starhub subscriber can help to answer the question on Channels 29 and 38. But I doubt anyone can clear the air over the 15 scrambled channels your soundtech receives.

So I think you can only know if it works after you have tried it out.

@Kiwi8

The above may partially explain why your setup didn't work. The other possibility is that, for example, chan 8 signal from starhub and the chan 8 signal from your own antenna may be out of phase - they travel by different paths - and cancel each other out.

If you are willing to give more info on what you did, I can try to figure out why it went wrong.

Hi,

I tried using a splitter to act as a "combiner" but it didn't work. I guess the reason is because the 2 signals are cancelling each other out. I think if I can filter out 224.25MHz to 503.25MHz on the Soundtech antenna then I should be able to get the result I want. Any device that can do this?
 

mrsun18

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Thanks for the advise..

I suppose like what you said, my relaying of antenna cable will give an"excuse" for starhub to point finger back to me.. (of course, i haven't try, i never know)..

In the event if they are not providing a solution for me, will I be able to get a signal "booster" of something like that in the market for such type of connection? I saw something in SL tower where it requires power supply into a small signal amplifier, made in china. can those help?
If you can confirm with your neighbours that they are facing the same issue, then you have a strong case. If this is so, then probably what starhub need to do is just to tweek their output slightly higher, which they are supposed to do anyway as part of routine maintenance, to compensate for their aging network/components.

Having said this, bear in mind that the signals that reach the tv set will be affected by aging component in the whole signal path. This includes starhub's network, the quality/aging of your internal wiring/connectors, the wall outlet plate and the interconnect between wall plate and the tv set. Finally, the sensitivity of the tv tuner does play a part in the reception when the signal strength is marginal.

Talking about signal boosters, your signal has dropped to a low value such that noise (grainy) started to be noticeable. If you use a booster, you boost up the noise and signal in the same ratio. In addition, the booster injects its own noise into the signal. Whether it works or not I am not sure because what I say is based on theory. Besides the question of reliability, be aware of safety issue also because these are ac powered (ac powered appliances need to have a safety mark for sale in sg).
 

mrsun18

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hv u tried using different RF cable~? :s11:
Cables do play a part. For an illustration to see the impact of using different cables:

RG 6 - 6.1dB/100 ft cable loss @ 1GHz
RG59 - 12 dB/100 cable loss @ 1 GHz.

The difference between the two cables, (12 - 6.1) dB/100 ft round to 6 dB/100 ft @ 1GHz.

If we are talking about interconnect between wall outlet and tv set, for a length of say 10 ft, the difference is 0.6 dB @ 1 GHz.

The use of better cable has no major impact on improving the signal level to the tv for short cable run, such as those used for interconnect.
 

sunsetbay

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Cables do play a part. For an illustration to see the impact of using different cables:

RG 6 - 6.1dB/100 ft cable loss @ 1GHz
RG59 - 12 dB/100 cable loss @ 1 GHz.

The difference between the two cables, (12 - 6.1) dB/100 ft round to 6 dB/100 ft @ 1GHz.

If we are talking about interconnect between wall outlet and tv set, for a length of say 10 ft, the difference is 0.6 dB @ 1 GHz.

The use of better cable has no major impact on improving the signal level to the tv for short cable run, such as those used for interconnect.

on paper probably u r right~

base on my personal encounter and few forumers experiences~ it did make a big difference between rg6 & rg59~ it was also standard cable use for starhub network due to the high bandwidth nature~

many yrs back, i encountered poor reception on ch5 & U, it was working perfectly all along, my cable was less than 2m~ i never suspect it was my cable problem since the rest of the channels were working perfectly~ i called starhub to check my signal~ the technician came to my home and measured the signal strength for all the tv points~ signal was ok but the tv reception for ch5 was not~ then the technician gave me a belden rg6 (they billed me few dollars for it on my maxonline acc) and the reception was perfect again~

i shared this experience on hardware clinic few few tvcard enthusiasts many yrs back and it resolved their prob as well~ :s22:
 

Kiwi8

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on paper probably u r right~

base on my personal encounter and few forumers experiences~ it did make a big difference between rg6 & rg59~ it was also standard cable use for starhub network due to the high bandwidth nature~

many yrs back, i encountered poor reception on ch5 & U, it was working perfectly all along, my cable was less than 2m~ i never suspect it was my cable problem since the rest of the channels were working perfectly~ i called starhub to check my signal~ the technician came to my home and measured the signal strength for all the tv points~ signal was ok but the tv reception for ch5 was not~ then the technician gave me a belden rg6 (they billed me few dollars for it on my maxonline acc) and the reception was perfect again~

i shared this experience on hardware clinic few few tvcard enthusiasts many yrs back and it resolved their prob as well~ :s22:
They so kiam ah, still billed u a few dollars? :o

There was a time when I got StarHub technicians coming over to service my STB, I managed to get a cable from them free. :o
 

mrsun18

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@sunsetbay

I understand that you and some other forummers solved certain signal problems by changing to a better quality cable. And since the problem was solved it was perfectly logical to conclude that a better quality cable made the difference.

But for those who are familiar with antenna theory, where rf is concerned, there is a peculiar phenomenon when a short circuit is an open circuit and an open circuit is a short circuit. A connection that seemingly looks ok but not properly tightened may allow signal of certain frequencies to pass through without hindrance while signal of some other frequencies may not pass through properly, as what you and others have experienced.

I too had encountered such problem in the old days when I used to fabricate my own interconnect with the old banana type plugs. Becasue I was aware of this phenomenon, I redo the connections between the plugs and the cable which solved the problem.

For your case, starhub has verified that all channel signals were ok at their end, but you have problem with chan 5. Changing the cable to one with a better specs or to one with the same specs is one way to solve the problem. In any case, starhub would use RG6 because they don't have RG59. This is a bit like having a faulty circuit board. Change the board or use one which is 'better" will settle it. But if you know that it is a faulty component and you know how to trace and repair it, you can choose to go this way.

In the case of wolf24 wolf, he experienced less than ideal reception only during certain period in the evening. That was the period when more people watched tv. After 11 pm reception returned to normal. My diagnosis is therefore insufficient signal during this period. If it is an interconnect problem, the poor reception will most likely to be present all the time.

Actually it is very easy to measure the signal level for different channels at the wall socket, either by starhub (as done in you case) or by other qualified technicians, if they have the meter. But service charge applies unless starhub network is faulty or if own technician is engaged. Service is free also if it involves a hdb point.

Edit: Just in case if you are still not convinced of my cable loss theory. At 200MHz which is near Chan 5 frequency of 175 MHZ, the difference in cable loss performance of the RG6 and RG59 is even lower. For RG59, it's 4.5 dB/100 ft and 2.8 dB/100ft for RG6. The difference is (4.5 - 2.8) or 1.7 db over 100 ft run. So for a 10 ft interconnect it's only 0.17 dB improvement in signal level for RG6.
 
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cscs3

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Cables do play a part. For an illustration to see the impact of using different cables:

RG 6 - 6.1dB/100 ft cable loss @ 1GHz
RG59 - 12 dB/100 cable loss @ 1 GHz.

The difference between the two cables, (12 - 6.1) dB/100 ft round to 6 dB/100 ft @ 1GHz.

If we are talking about interconnect between wall outlet and tv set, for a length of say 10 ft, the difference is 0.6 dB @ 1 GHz.

The use of better cable has no major impact on improving the signal level to the tv for short cable run, such as those used for interconnect.

Guess is much less as not all channel run @ 1Ghz. Important one is if the signal reach the TV at required signal level. Usually the output from TV point has signal much higher then requirement.

A lot of cases, it is not the cable itself but the connector or poor connection in the connector during manufacturing.
 

mrsun18

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Guess is much less as not all channel run @ 1Ghz. Important one is if the signal reach the TV at required signal level. Usually the output from TV point has signal much higher then requirement.
Correct, cable losses increase exponentially with frequency. Designers do take account this effect. The use of 1GHz is used as a convenient reference point for comparison. You may have missed out my comparison at 200MHz in the Edit.

Generally, min signal level of 60dB and 48dB are the norms for good analogue and digital reception respectively. To cater for effect of aging installations and different tuner sensitivity, they are set much higher. It is not unusual to get 70 dB output.

A lot of cases, it is not the cable itself but the connector or poor connection in the connector during manufacturing.
Ya, nice complementary comments to what I was trying to explain.
 

sunsetbay

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@mrsun18

i got no doubt on your technical knowledge but to say starhub uses rg6 bcos they dun hv rg59 sounds unconvincing~ rg59 is cheaper, more flexible and widely available however its unsuitable for the higher frequency range bandwidth used in starhub cable~

anyway, i hope wolf24wolf resolve his prob and share his findings here~ :D
 

mrsun18

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@mrsun18

i got no doubt on your technical knowledge but to say starhub uses rg6 bcos they dun hv rg59 sounds unconvincing~ rg59 is cheaper, more flexible and widely available however its unsuitable for the higher frequency range bandwidth used in starhub cable~
I may sound unconvincing but I can't see the reason why starhub should keep stock of RG59 when they don't use it. Notwithstanding your points about RG59, starhub has different priorities from consumers. Nonetheless, you may know better. I am all ears...

anyway, i hope wolf24wolf resolve his prob and share his findings here~ :D
As I said earlier, sometimes there may be more than one contributing factor to a problem:
...
Having said this, bear in mind that the signals that reach the tv set will be affected by aging component in the whole signal path. This includes starhub's network, the quality/aging of your internal wiring/connectors, the wall outlet plate and the interconnect between wall plate and the tv set. Finally, the sensitivity of the tv tuner does play a part in the reception when the signal strength is marginal...

Coincidentally, there was an article written by Dr Andy Ho published in yesterday's Straits Times, about evidences given by so-called expert witnesses in courts. He found a number of the evidences given were subsequently found wrong and judgements were overturned on appeal.

So I am suggesting that what I said may turn out to be the wrong diagnosis. I am just as eager to know what is the final outcome.

Cheers.
 

sena11

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help

hi everyone,

i living in HDB.

got 2 tv point. in living room and room.

the living room tv point is connect to hdb antenna.
which i want to change the point to connect to scv point.

any advise?
possible cost of the change.
or instruction that i can change it myself.
 
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wolf24wolf

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@mrsun18

anyway, i hope wolf24wolf resolve his prob and share his findings here~ :D

Sad to say.. haven't have the chance to explore the suggested methods yet due to work load.. no time for tv hence now got to put the problem aside first.. haha.. will keep everyone update if any of the method succeed/fail..
 

mrsun18

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hi everyone,

i living in HDB.

got 2 tv point. in living room and room.

the living room tv point is connect to hdb antenna.
which i want to change the point to connect to scv point.

any advise?
possible cost of the change.
or instruction that i can change it myself.
Call starhub.
 

epichouse

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Hi, does anyone know any shops that sell DVB-T receiver set top box for TV at the lowest price? Remembered seeing one at only $99 in Sim Lim!
 

Soul77

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Hi, does anyone know any shops that sell DVB-T receiver set top box for TV at the lowest price? Remembered seeing one at only $99 in Sim Lim!

You can try aliexpress. They're quite ok, all my items arrived.

The latest DVB T2 terrestrial digital television receiver,Compatible with the dvb t and dvb t2 DVB T2 9003 HDMI+USB+PVR dvb t2-in Set-top Boxes from Consumer Electronics on Aliexpress.com

If you're lucky, the same STB can even be used when Singapore moved to DVB-T2 by end of this year
 

Streetwise

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Soul77

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So u bought a set? If so, it would be great if u can give a review of the product??

Not this model. I'm waiting for dongle version of DVB-T2. However I already bought the usb dongle version of DVB-T. Works ok for HD5, Digital 5, etc.
 

epichouse

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Hi, my small tv cant receive sg channel signals properly(grainy image, ghosts etc etc) while it can receive most of the malaysian signals just fine, anyone knows how to fix this? tried buying a antenna for it but no matter where i put also poor signal, plug it into the wall box receives worse singapore signals than if i used a antenna one.. help..
 

mrsun18

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Hi, my small tv cant receive sg channel signals properly(grainy image, ghosts etc etc) while it can receive most of the malaysian signals just fine, anyone knows how to fix this? tried buying a antenna for it but no matter where i put also poor signal, plug it into the wall box receives worse singapore signals than if i used a antenna one.. help..
Need to tell us you are in HDB, pte condo or landed property?
 
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