Welcome Guest ( Log In | Register )

Bump Topic Topic Closed RSS Feed
7 Pages « < 4 5 6 7 >Bottom

Outline · [ Standard ] · Linear+

 Digital TV Station Malaysia, How do I tune to digital TV station?

views
     
dayojah
post Oct 12 2019, 09:54 AM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
More powerful transmitters are expensive, it looks like MyTV has gone for the the low cost option. The original DTTV tender demanded indoor coverage in the KL area
dayojah
post Oct 13 2019, 11:10 AM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
Indoor coverage in urban areas was a key requirement in the original tender. RTM1 had to be easily available to the masses.
dayojah
post Oct 14 2019, 11:06 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
QUOTE(joshhd @ Oct 14 2019, 10:58 PM)
user posted image
A close up shot of the 5 element UHF antenna being install at viewer's home by the authorised MYTV installer.

user posted image
This antenna so cute and small. Feel like want to buy liao  sweat.gif

*
I see four elements there, two directors, one reflector and a folded dipole

To me it looks too broadband, those director elements are very short at <700 MHz and closely spaced
It will work, but not very well
dayojah
post Oct 14 2019, 11:20 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
The folded dipole gives a better match to Yagi antennas. Many cheap ones just use a simple dipole connected to the coax - simpler to make.
Always the second element added is the reflector at the back, slightly longer than the dipole. This gives the biggest jump in gain
After this director elements are added at the front. These are shorter and more and more are added to increase gain, but this is diminishing returns. You end up with a very long antenna like those you see in Muar aimed at Singapore. Very fragile and spoiled by heavy birds

I prefer 4 Bay Bow-Ties like this, not available in Malaysia unfortunately
https://www.solidsignal.com/pview.asp?p=HDB4X
dayojah
post Oct 14 2019, 11:54 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
They get really creative counting elements these days.
The second last is probably the best.
Why don't they make them 470Mz to 700 MHz, making a Yagi work all the way up to 860 MHz really spoils the performance
dayojah
post Oct 15 2019, 05:36 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
DTTV reception is all or nothing, the decoder should not be able to see only some of the channels in a MUX.
This sounds like a decoder problem or your TV not displaying HD/SD properly

dayojah
post Oct 15 2019, 11:37 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
QUOTE(shaun_kok @ Oct 15 2019, 09:15 AM)
Got point too. Especially when after switchover, frequency from 700mhz upwards are unused anymore for TV after Digital TV networks has moved down to below 698MHz.
*
This page compare Yagi Uda designs with a variety of upper channel cut offs.
Note how the peak effective aperture and hence gain goes down with broader bandwidth, also the peak gain is in a band where there will soon be 5G and it will interfere with your DTTV
https://ypylypenko.livejournal.com/67090.html
dayojah
post Oct 17 2019, 10:07 AM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
The old analog TV system had separate transmitter towers for the various channel owners, why you see so many masts on Bkt Besi
Turning these off is between the channel owner and the MCMC, so they don't go off all at the same time
dayojah
post Oct 18 2019, 10:27 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
It was a horrible project to bid for, most sites are owned by TM. The MCMC did not allow TM to bid as they did not want a GLC to own the capital cost debt, but TM made a LOT of of money from making the channels use TM maintenance and tower rental
dayojah
post Oct 20 2019, 11:45 AM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
RG6 is the cheapest and most available low loss cable
A lot of old TV coax is rubbish, minimal shielding or solid and lossy dielectric intended for the original RTM1 low band VHF
dayojah
post Oct 20 2019, 10:00 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
QUOTE(joshhd @ Oct 20 2019, 12:04 PM)
Besides 3C-2V and 5C-2V coaxial cables which was commonly used for terrestrial TV during the 70s-80s, is there any other cable types used for receiving analogue terrestrial TV back in the old days in Malaysia?

Some people tried using their existing old 3C-2V or 5C-2V cables (either used or abandoned for analogue TV reception last time) to try receive digital TV signals, some can get signal (especially using signal boosters), some would experience unstable or no signal at all.

In simple words, it is considered as old and rubbish cable in today's context.

Might as well as replace to RG6 coaxial cable to get the best reception possible in the area (subject to antenna and surroundings), and the use of older signal boosters for analogue TV are not longer needed, or must not be in use to receive digital TV.

Correct me if I'm wrong.
*
3C-2V is 41dB/100m @ 750 MHz
5C-2V is 29dB/100m @ 750 MHz
RG6 is 18dB/100m @ 750 MHz

The 3C-2V should be skipped, the 5C-2V is ok at shorter lengths if in good condition
dayojah
post Oct 20 2019, 10:04 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
The old coax types were only for VHF band I and III over any distance, remember that it was latecomer NTV7 that first used UHF
dayojah
post Oct 20 2019, 10:41 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
QUOTE(keatliang2005 @ Oct 20 2019, 10:34 PM)
thanks for the insight
smile.gif
for past two days, i was unable to resolve, unable to received RTM based channel, and only prima media one. signal strength is about 54%, now i isolate the hdmi cable with aluminium foil. and it works.  rclxms.gif

my antenna is high rise building master antenna system.

hope this help others  thumbup.gif
*
Sounds like you have a cheapo hdmi cable
dayojah
post Oct 20 2019, 11:11 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
QUOTE(keatliang2005 @ Oct 20 2019, 10:54 PM)
the hdmi came with the decoder which i get it from lazada  sweat.gif
*
It was bundled free, so cheapo then.
Don't get ripped off for exotic hdmi cables from hifi shops, they are often trash in a fancy box
dayojah
post Oct 21 2019, 09:35 AM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
Cable does not wear out with age, it is spoiled by water getting in or rubbing against something
dayojah
post Oct 21 2019, 10:42 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
Restacking will help for several reasons, but interference levels rise if anything at lower frequencies.

Path loss from the transmitter to your home is lower
Cable losses lower
Rain and wet roof loss lower
Receiver sensitivity usually better
dayojah
post Oct 21 2019, 10:52 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
This is a good summary of what has gone wrong with hdmi with measurements
https://interferencetechnology.com/hdmi-cables-emi/
dayojah
post Oct 22 2019, 07:46 AM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
QUOTE(joshhd @ Oct 22 2019, 02:38 AM)
Hmmm... I have some questions wanna ask...
<600MHz = frequencies lower than 600MHz (example 470-606MHz)
>600MHz = frequencies above 600MHz (example 606-742MHz)


1. If the <600MHz part of UHF frequency seems to bring more benefit than >600MHz, and once analogue TV has fully switched off, what are the other benefits of using >600MHz then?
Seems that >600MHz brings more disadvantages than advantage to me.

And why some other countries (assuming already complete ASO), still uses >600Mhz frequencies for DTT if using frequencies that are <600MHz brings more benefit?

2. What are the other things that is on <600MHz which could potentially cause interference? Wireless microphones?  hmm.gif

3. Once 700MHz is used for 4G/5G, how would it affect viewers that uses UHF antenna that supports almost entire range of UHF TV frequency (e.g. 470-869MHz)?
If the DTT frequencies is re-stacked to <600MHz, will 4G/5G signal from 700MHz band still causes interference to those DTT reception?

4. What if someone can't get digital TV signals yet not sure what's the cable type used, especially if the cable jacket doesn't have any labels like 3C-2V, 5C-2V or RG6 or RG6/U?
Not everyone knows how, and willing to identify/measure the cable diameter like that. If this happens, how would you advise the person to check what's the cable type?
(At least if the person knows that if it's RG6 type, then at least it is safe to assume the cable type is ideal, and unlikely experience much cable loss like 3C-2V type (unless cable is damaged).
*
1) The only reason for using >600MHz is shortage of channels, eg Singapore is currently allocated all of the 500MHz block - a ridiculous situation with DTTV
The USA is already reallocating above 620 MHz for other services

2) Cables tend to radiate more in the VHF than the UHF due to their length, I have seen this in the SIRIM labs many times. The source can be Ethernet, hdmi ( my link above shows plenty of low uhf ), switched mode power supplies and any computer.

3) I have seen MATV systems having to install a low pass filter to reduce LTE interference in Europe

4) If the cable is not marked, it is probably rubbish.
dayojah
post Oct 22 2019, 06:02 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
The stronger signal from using the lower channels more than makes up for greater noise from digital electronics

Singapore used to use channel - space - channel- space - channel before ASO and they had a lot of channels before Malaysia got beyond TV3.
They filled the 500 MHz block because they got there first and Malaysia did not fight it at the time. This is crazy now after ASO

There is no 700 MHz LTE here yet, but tests have found issues with MATV in Europe, where 700 MHz LTE is coming very soon.
dayojah
post Oct 28 2019, 07:18 PM

Regular
******
Senior Member
1,276 posts

Joined: Sep 2018
From: Ampang
Use RG6 and the cable attenuation will only be about 4dB, so no point in using a booster.
Getting the antenna a bit higher and the cable connected main element away from other metal like that metal frame will have far more benefit.

7 Pages « < 4 5 6 7 >Top
Topic ClosedOptions
 

Change to:
| Lo-Fi Version
0.2363sec    0.49    7 queries    GZIP Disabled
Time is now: 3rd December 2025 - 04:02 AM