Where can get good A-B switch?

[rexall]

Thu 13 Jun 2013, 6:38 pm

Hi All,

I need an A-B switch to switch back & forth between KTV (local cable) and True satelite, both standard coaxial cables. I have bought two cheap, plastic A-B switches for 50 THB and they don't work very well; the signals are dirty and I get snow bleeding over from True to KTV.

Problem is I can't find more heavy duty switches anywhere. I am in Khon Kaen. Went to all the shops in Tuckom, Central Plaza, KTV Office, TRUE office, STV store, PowerBuy . . . Nobody has a clue. They all point to poor Mr. Amon at Tuckom, except that he no gotti either!

Seems odd that such a standard piece of equipment is so hard to find. Do people not use these any more?

Any suggestions where I can get one in Thailand, especially a shop that is willing to send me one in Khon Kaen? Baring that, any internet sources that ship to Thailand?

Thanks for your help.

[monty]

Not sure I understand.

I do understand KTV coming in through coax and straigh to your TV, but I never heard of Truevisions coming in through coax straight to your TV. Truevisions normally goes into a receiver (satellite mostly, or a cable box in Bkk), and then on to your TV through regular AV cable or hdmi cable.

Maybe a bit more info so we can help out?

[rexall]

Thanks for your reply, Monty.

Trust me. Both are standard coax cable. The True one is an extension coming from the downstairs True decoder to the teevee upstairs. But that is neither here nor there. What I need is an A-B switch that does a better job of isolating one signal from another than the cheap plastic ones I got. The box downstairs true satelite box connects via hmdi, so there is no conflict with KTV which uses a completely different input in the teevee.

Upstairs, without the A-B switch, plug the true cable directly into the teevee and the signal is perfect. Unplug true, and plug in KTV cable, and the signal is perfect. Us the A-B switch, and the KTV picture gets a little "snow." It's not terrible, but as I am paying for two subscriptions, I don't want not stink'in snow!

[monty]

OK, gotcha!

It's actually a bit of problem, due to the very nature of the signals pumped through the coax cable.

They are actually at a frequency which is designed to make for good transmission through air and even buildings and obstacles. They are exactly the same signals/frequencies you can pick up with an old style TV antenna.

Which makes it extremely difficult to separate them simply by switch, as they will readily jump over to the other cable even if physically cut by a switch.

In the old days I used to fiddle with them (back when every VHS recorder simply used coax to connect to your TV) and always had the very same problem.

What you need does exist but I guess it is getting out of fashion and becoming harder to find in your average shop. I'll attach a link to one such device (on amazon), which you might be able to use as reference. Most important to look for is the high isolation (85 dB or more) to avoid crosstalk between the cables...

http://www.amazon.com/C2G-Cables-41015-Isolation-Switch/dp/B0002J2P2A/ref=pd_cp_e_0

If not found locally, I'm sure ebay etc. will also have those items listed, so with a little patience it shouldn't be too hard to get one delivered to your doorstep.

[rexall]

Thanks, Monty. Yup. That's the little devil I was looking for : "Isolation is in excess of 90 dB to eliminate interference from external devices and crosstalk between connected devices"

Yes, my mind was going back to the days of Wine, Roses and VCR's. Probably cheaper to just bite the bullet and have Amazon send it to me than spending a day running around Bangers looking for it. And I have exhausted all the possibilities up here in the frigid Northeast of Isaan!

Thanks, lah!

[innerspace]

One practical idea.... a short extender cable to make the connection accessible in front instead of behind the tv.

Then a simple pull this cable out and push this one in switch.

Manual switching process anyway and the equipment needed for this is available everywhere.

[joncl]

or a simpler option might be to change the frequency of the True boxes RF output (a setting on the older boxes - uses the UHF band) or for the new true HD boxes, buy and use a variable modulator from the True box - use the a/v output from the true box to the mod then select on the mod a frequency not used by KTV and off you go. Mods are about 600-1,500

[monty]

or a simpler option might be to change the frequency of the True boxes RF output (a setting on the older boxes - uses the UHF band) or for the new true HD boxes,  buy and use a variable modulator from the True box - use the a/v output from the true box to the mod then select on the mod   a frequency not used by KTV and off you go. Mods are about 600-1,500 

Done that before, but nowadays with cable companies jamming 100+ channels over the vhf and uhf bands it can be hard to find an empty space!

I also found the mods to be pretty powerfull and crosstalking into a wide area from the cable tv. I think some sort of attenuator could help there as well

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[Satcommlee]

I know exactly what you want, but I've never seen them in Thailand I'm afraid.

Maybe having 2 female sockets with the sources and a male connector you plug into the TV may do just as well.

Failing that you may have to order from abroad.

[Clendenin]

You might try Radio Shack. I bought a push button A-B selector switch there several years ago. Stores are in many of the shopping malls.

[monty]

You might try Radio Shack.  I bought a push button A-B selector switch there several years ago.    Stores are in many of the shopping malls.

Haven't seen a radio shack for ages here in Thailand.

There used to be one in one of the shopping malls on Ploenchit road (close to Chidlom) but afaik it's not there anymore...

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