Why can't I get DTV channels?

[RichCor]

You can't just use a Y-connector. It has to be a 'combiner' or 'diplexer' so the other's RF signals don't electrically leak back and interfere with the other input.

 

Once you have the analog and digital RF sources combined on one cable then, as you say, you use the remote on the TV to select either ATV or DTV source.  ...I don't know of many TV sets that allow you to easily switch between ATV and DTV sources, usually you have to choose just one in setup.

[johng]

You can try but I'm pretty sure the 100 analogue channels would be using some if not all
The frequency channel that the DTV channels are broadcast on and I guess the digital signal would loose

In Bangkok the digital channel frequency alocations are
26,36,40,44,32,29


Channel to frequency chart

[ddavidovsky]

I'm struggling to understand about the frequencies and also about backfeeding.

If a diplexer will combine the cables without problem, how about this?:

http://www.lazada.co.th/tpl-mixer-diplexer-tv-sat-sat-ant-tp-dpx01-15899298.html?ff=1

Cheap enough. Same issue with the threads though - not sure how to connect push-on cables to that.

[johng]

No you want to find a device that selects between 2 or more inputs with one output. Typically called a "switch" some can be remotely controlled the cheaper ones have push buttons.

The important thing is not to combine the 2 inputs you need each input isolated from each other and the switch conects one or other to the output one at a time.

 

 

[johng]

Dont worry too much about what connector it has cables can be found to convert between types.

[ddavidovsky]

18 minutes ago, johng said:

No you want to find a device that selects between 2 or more inputs with one output. Typically called a switch some can be remotely controlled the cheap ones have push buttons
The important thing is not to combine the 2 inputs you need each input isolated from each other and the switch conects on or other to the output.

Ok. I can't yet find such a coax switch though, except for CB radio use.

 

Sounds like the world needs a simple backfeeding filter device. I was hoping those diplexers did that job.

 

My TV remote, btw, does have a button labelled "ATV/DTV" which I assume switches between the two inputs.

[johng]

Something like this

http://m.ebay.com/itm/111289618374

[johng]

Or this
http://m.ebay.com/itm/Steren-200-310-A-B-Switch-Coaxial-2-Input-75-Ohm-5-900-MHz-UHF-VHF-FM-AB-15-/221389002338?_trkparms=aid%253D222007%2526algo%253DSIC.MBE%2526ao%253D1%2526asc%253D20150519202348%2526meid%253D8b801f9c6d6241ed83b410d14655c883%2526pid%253D100408%2526rk%253D1%2526rkt%253D11%2526sd%253D111289618374&_trksid=p2056116.c100408.m2460

[Crossy]

13 hours ago, ddavidovsky said:

I'm struggling to understand about the frequencies and also about backfeeding.

If a diplexer will combine the cables without problem, how about this?:

http://www.lazada.co.th/tpl-mixer-diplexer-tv-sat-sat-ant-tp-dpx01-15899298.html?ff=1

Cheap enough. Same issue with the threads though - not sure how to connect push-on cables to that.

 

That should do the trick.

 

F connectors are readily available (usually the splitter / diplexer comes with them anyway), you should be able to get the beastie in Fortune. They need the co-ax with a solid centre core rather than stranded as this core is used as the centre pin of the connector.

 

[ddavidovsky]

20 hours ago, johng said:

Something like this

http://m.ebay.com/itm/111289618374

 

Thanks. If I can find one like that in Thailand I'll go for it. Paying $30-50 shipping for a $2 item sticks in the gullet a bit...

[ddavidovsky]

11 hours ago, Crossy said:

 

That should do the trick.

 

F connectors are readily available (usually the splitter / diplexer comes with them anyway), you should be able to get the beastie in Fortune. They need the co-ax with a solid centre core rather than stranded as this core is used as the centre pin of the connector.

 

Alright, I'll give it a try.

 

Thanks everyone, I've learned a lot in this thread.

[ddavidovsky]

Update: got one of those splitters (from Amorn at Fortune) - doesn't work.

With ATV connected: ATV channels okay.

With DTV connected: DTV channels okay.

With ATV and DTV connected: no DTV channels (signal quality=zero), ATV channels okay.

Seems the DTV signal is too sensitive and gets obliterated this way.

Switched connectors don't seem to exist in Thailand, so I give up.

 

Last resort may be one of these 'combo' boxes:

https://www.aliexpress.com/item/HOT-Android-5-1-DVB-T2-Terrestrial-DVB-S2-HD-AC3-Satellite-IPTV-Combo-Convertor-Receiver/32772402652.html?spm=2114.01010208.3.18.26o4Cq&ws_ab_test=searchweb0_0,searchweb201602_1_10152_10065_10151_10068_10136_10137_10060_10138_10155_10062_437_10154_10056_5010020_10055_10054_10059_303_100031_10099_10103_10102_10096_10052_10053_10142_10107_10050_10051_10084_10083_10080_10082_10081_10110_519_10175_10111_10112_10113_10114_10182_10185_10078_10079_5030020_10073_10123_10189_142,searchweb201603_9,ppcSwitch_5&btsid=f0ba4ff0-735e-4edb-84de-aaebd2bd6f9e&algo_expid=f90cf1d5-72f6-48ce-acf6-f1f55d8777c7-2&algo_pvid=f90cf1d5-72f6-48ce-acf6-f1f55d8777c7

It includes Kodi, which means I won't need the Raspberry Pi, so that will free up an HDMI port and let me have everything connected at the same time. I didn't want to go buying extra stuff like this, but it does include Android which might be useful.

 

[johng]

Update: got one of those splitters (from Amorn at Fortune) - doesn't work.
With ATV connected: ATV channels okay.
With DTV connected: DTV channels okay.
With ATV and DTV connected: no DTV channels (signal quality=zero), ATV channels okay.
Seems the DTV signal is too sensitive and gets obliterated this way
 

Yes exactly as I suggested would happen....

You need a SWITCH not a
splitter/combiner.
They do seem to be rare as hens teeth in Thailand.


Here is one from ebay cheap shipping
m.ebay.com/itm/2-WAY-A-B-Coaxial-Coax-RF-Switch-Manual-Selector-Push-Button-Cable-TV-Antenna-/122323558916?_trkparms=aid%253D222007%2526algo%253DSIC.MBE%2526ao%253D1%2526asc%253D20150519202348%2526meid%253D4546a8e8bf8943bc8bf249f94e6b70fb%2526pid%253D100408%2526rk%253D1%2526rkt%253D1%2526sd%253D112429205259&_trksid=p2056116.c100408.m2460

[RichCor]

2 hours ago, johng said:

3 hours ago, ddavidovsky said:

Update: got one of those splitters (from Amorn at Fortune) - doesn't work.

With ATV connected: ATV channels okay.

With DTV connected: DTV channels okay.

With ATV and DTV connected: no DTV channels (signal quality=zero), ATV channels okay.

Seems the DTV signal is too sensitive and gets obliterated this way.

Yes exactly as I suggested would happen....

You need a SWITCH not a splitter/combiner.
They do seem to be rare as hens teeth in Thailand.

 

Yep, same frequencies (channels) being used for both.  

A physical switch is the only way to go.