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Cable TV Scanning

Whiskey_River
Explorer
Explorer
2 TV's, one in living room and one in bedroom.
Scan the living room TV on cable an it pick's up all 50 channels on the park cable system. (Optel) When I scan the bedroom TV on cable it will not pick up the local CBS,NBC,ABC, etc. It will not pick up channel 2 thru 7 for some reason, but picks up the other 43 channels. The power antenna button is not pushed and the TV scan is on cable.
If I run the cable directly to the TV thru the front door it will scan all 50 channels fine. Then back thru the cable into the 5er it does not hold the scan and does not show the low channels.
This did the same thing with my old 5er, and now I have a new 2020 5er and the same thing..
Any idea's out there??
Thanks.
17 REPLIES 17

Gdetrailer
Explorer III
Explorer III
FlatBroke wrote:
Canโ€™t you put those termination caps on the used splitter terminals and have it work?


Flat broke,

Termination caps in this case will not help.

Termination caps at one point of time would have been used to stop "reflections" of signals back to the other sets. But that was when all broadcasts were analog and those reflections sometimes would be strong enough to show up as a light offset "Ghost" in the video since the reflection was delayed.

Nothing special about termination caps, they are a 75 ohm resistor..

Digital broadcasts seem to be able to cope with some reflections to a certain extent.

The thing is, with digital the TV tuner must have PLENTY of signal to overcome the noise around the antenna or in the antenna path to work correctly.

My experiences with analog and digital TV tells me that unless you are right under the TV broadcast tower, that you NEED to eliminate as much of the loss in your antenna path/system as possible..

That pretty much means ALL passive splitters must go.. The problem with that is many RVs (and this applies to sticks and bricks) will have two or more TVs and a three or 4 way passive splitter..

With a 3 or 4 way splitter, you may as well just stick a 6ft piece of wire in the antenna input, you loose that much signal.

To get ALL TVs back into working order you will want a AMPLIFIED COUPLER which is a fancy way of saying a splitter with a low gain preamp for each output.. This way each output now has some signal gain over the noise level.

I ran into this during the analog to digital transition, I had a eight port passive splitter on my sticks and bricks to feed my whole home MATV system..

Once channels started moving to digital, I lost them.. I found for the most part I was too far from the stations to reliably get the digital channels with what used to work fine with analog broadcasts.

I resorted to buying a $180 amplified coupler and that restored all of my locals and only a couple of the far distant channels..

My locals are a min of 50-60 miles from me.. My far distant channels (across state lines) are 80-100 miles (I used to get analog channels up to 120miles away).

Gdetrailer
Explorer III
Explorer III
Whiskey River, Thanks for the update!

Glad that "cleared" things up for you

It is a common problem that can drive folks crazy and RV manufacturers don't realize is a problem.

FlatBroke
Explorer
Explorer
Canโ€™t you put those termination caps on the used splitter terminals and have it work?

Hitch Hiker
"08" 29.5 FKTG LS

Whiskey_River
Explorer
Explorer
Answering my post from the middle of December.
Gdetrailer you were right. I bought an RCA 4way video amplifier at Lowes. Its like a power splitter like you sent the picture of. Says it amplifies signal up to 10dB. It has a plug to power it. Cost 25 bucks.
Any way after removing a wall in the basement and standing on my head and reaching around and under enuf wire, cable, piping, & hydraulic lines to power the space shuttle, I got the old 4 way splitter out and put in this amplifier and it works.
I now get channel 2,3,4,5,6 & 7, in the bedroom TV. Those are channels pbs,cbs,nbc,fox,abc & cw. Channel 2 & 3, pbs & cbs has some pixelating but the others are good. I know those 2 channels are at the end of the band and I have had that pixelating other places as well....
Thanks all.....

Gdetrailer
Explorer III
Explorer III
Whiskey River wrote:
Continuing my saga of not getting channels in the bedroom TV, yesterday I ran cable to my neighbors pedestal beside me. Same thing, will not pick up channel's 2 thru 7, the local channels. Then I ran cable to a pedestal behind me in a new part of the park. Same story. I took out a part of the bulkhead in the storage area and I can see a splitter that looks like its at least a 4 part. But to get to it, I need to take out another wall. That will take some work. If I knew that was the problem, I would do it. Don't know what else it could be. The cable system is putting out he channels & the TV will pick up them, but will not in the bedroom unless you run the cable directly to the TV. Other than the living room & bedroom, there is a hook up for a TV in the kitchen & in the storage area to add a TV if you want to. If I take the wall down to get to the 4 way splitter I will remove it and just install 2 way splitter in place of it to get just living room & bedroom.....
Gdetrailer thanks for all that info. I understand some of it. I'm basically the guy that plugs into he pedestal & the rig & its suppose to work....


Yep, 4way splitter, that is most likely the culprit :M

If no need for the other two connections ditching the 4way and replacing with a 2way should take care of the issue. Sadly, sounds like a lot of work to get at it.. Doesn't sound like the cable Co is supplying as much signal as they should be, have seen them put in 4ways in homes and work fine on all TVs.. But in a park setting they most likely have very few home runs back to the cable main trunk so there most likely is dozens and dozens of splitters in your park which is a buzz kill for getting enough signal..

IF you needed 3 or 4 ports I would recommend an amplified coupler. Amplified couplers as the name says, includes a low noise preamp on each port output.. Typically gives you a 7 DB or so GAIN on EACH PORT.

Although, even if you still only need two ports, this coupler will be a upgrade over the passive splitters and you might find not only the cable works better but event the OTA antenna also if you need or want to use that.





That one is a 4 port, 54mhz-1Ghz to outputs and has 5Mhz-42Mhz return back to the input (used for Cable companies cable box communications).

I don't know how good that one is, I have a different brand 8 port that I use in my sticks and bricks for OTA outdoor antenna system, it was the only way I could get TV after they switched OTA to all digital.

Found this one HERE

54Mhz is plenty low, that will work fine with Analog TV channels down to CH2.

Uses a 120V to 15V DC wall hugging plug but since it is 15V DC you can rewire to use your 12V battery system (just pay close attention to the polarity of the splitter plug side)..

Whiskey_River
Explorer
Explorer
Continuing my saga of not getting channels in the bedroom TV, yesterday I ran cable to my neighbors pedestal beside me. Same thing, will not pick up channel's 2 thru 7, the local channels. Then I ran cable to a pedestal behind me in a new part of the park. Same story. I took out a part of the bulkhead in the storage area and I can see a splitter that looks like its at least a 4 part. But to get to it, I need to take out another wall. That will take some work. If I knew that was the problem, I would do it. Don't know what else it could be. The cable system is putting out he channels & the TV will pick up them, but will not in the bedroom unless you run the cable directly to the TV. Other than the living room & bedroom, there is a hook up for a TV in the kitchen & in the storage area to add a TV if you want to. If I take the wall down to get to the 4 way splitter I will remove it and just install 2 way splitter in place of it to get just living room & bedroom.....
Gdetrailer thanks for all that info. I understand some of it. I'm basically the guy that plugs into he pedestal & the rig & its suppose to work....

Retired_JSO
Explorer
Explorer
We have a Summit TV in the fiver living room and a Vizeo in the bedroom. The Vizeo picks up almost twice as many channels as the Summit on the same park cable.

Gdetrailer
Explorer III
Explorer III
BB_TX wrote:
Channels 2-13 are VHF frequencies and channels 14 and higher are UHF frequencies. It may be that TV is filtering out, or cannot receive, the VHF frequencies. Could also be a menu selection.

To compound the problem, the displayed channel is not necessarily the actual transmitted channel.


Cable TV unlike OTA broadcasters do not have to follow any FCC rule on what and how and what order things are put on the cables they run or even high high of channel frequencies they can go, they often have channels outside the OTA broadcasters range.

It can be Analog, analog/digital or all digital.

NTSC was all analog and that is where Ch2 is broad coast on Ch2.

ATSC is OTA digital, cable systems typically do not use ATSC, instead they use QAM which is a bit more compact and has the advantage of cable cos enabling the private bit to scramble it..

Most modern TVs include tuners which are able to receive NTSC, ATSC and QAM (be aware, although there have been TVs made that did not have QAM capable tuners even though they have ATSC).

With the digital channels, they are not always broadcast on the old analog channel that they may indicate. Example, CH2.1 most likely is not broadcasted on analog CH2 frequency but instead it can be "MAPPED" from the old analog channel 30 in UHF.

The digital channel setup allows broadcasters and cable companies to keep the old analog channel "name" but yet actually modulated on a completely different frequency.

It is also called "virtual channels".

On those TVs IF you see CH2, CH2.0 or sometimes CH2-0 that IS an analog channel and it IS the real CH2 modulated on CH2.

If you see CH2.1, CH2.1, CH2-1 THOSE are DIGITAL channels and those most likely are modulated on a completely different analog channel.

Some TVs may have a "ant" or "OTA" or "AIR " vs Cable or CATV setting in the menu. For these, you will need to manually select between OTA and CABLE and rescan.

Some TVs actually do not have ANY settings between OTA or cable, those tuners require no manual intervention and will scan ALL possible OTA AND CABLE modulation frequencies. These ones I have seen them search all digital channels first, then scan for analog channels and once all searches have completed it will return you back to menu or to the first lowest channel found.

Lately, now that FCC has released Cable Companies from the "must carry" rules which required Cable companies to provide any LOCAL OTA broadcast "in the clear", they are no longer required to keep open channels which typically were modulated as analog NTSC.

Many cable companies have moved to all digital but that digital is not QAM, instead they are now using a streaming method that is not compatible with QAM tuners and requires the use of a cable converter "box" which is the size of a pack of cigarettes. Cable companies using this method must supply customer with at least one free, no charge converter.

The streaming convert box in the OPs situation obviously does not come into play here but it needed to be explained for clarity.

So, as you can see, it is not a simple cut and dry situation.

Whiskey_River
Explorer
Explorer
OK Thanks all. Today I will try to locate the splitter and make sure it is 5MHz - 1GHz
Here is what I have done so far.
Direct hook up with the cable from the pedestal to the cable input in the 5er & scan the living room TV and all 49 channels on the campground system, (Opticaltel) work and are crystal clear, the bedroom TV does not pick up channel 2 thru 7. These channels are 2 PBS, 3 CBS, 4 NBC, 5 FOX, 6 ABC, 7 CW
It scans all and starts with channel 8, USA on thru channel 49 and all cable channels are crystal clear.
I disconnected from the 5er hook up & ran the cable from the pedestal directly to the bedroom TV thru the front door directly into the TV and it scans all channels including 2 thru 7 and works. Then when you disconnect and hook up to the system, 2 thru 7 does not work.
I disconnected the living room TV and ran the cable from the cable input there thru the inside of the 5th wheel directly into the bedroom TV and it scans all channels including channel 2 thru 7 comes in crystal clear. Then when you replace the bedroom to the cable input there, channel 2 thru 7 does not come in...
So the TV's both work and will broadcast those channels and the cable system is putting out the signal for those stations. But for some reason the bedroom TV will not pick up those 6 channels on the system the way it is wired now.....
Before I get into the spaghetti/spider web of cable, wire, hydraulic lines and piping behind that wall in the storage area, I will try to run to another pedestal and see if that works. If not, then into the spaghetti/spider web looking for the splitter....

Bill_Satellite
Explorer II
Explorer II
I would like to post how OTA channels 2 and above (is it 56 or 62) have nothing at all to do with CABLE channels but I will not. I should.....no....I will not!
What I post is my 2 cents and nothing more. Please don't read anything into my post that's not there. If you disagree, that's OK.
Can't we all just get along?

wa8yxm
Explorer III
Explorer III
One possible issue is the ANT/Cable setting. SOME channels (IE 3) are common to both. Some are not .
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

BB_TX
Nomad
Nomad
Channels 2-13 are VHF frequencies and channels 14 and higher are UHF frequencies. It may be that TV is filtering out, or cannot receive, the VHF frequencies. Could also be a menu selection.

To compound the problem, the displayed channel is not necessarily the actual transmitted channel.

Gdetrailer
Explorer III
Explorer III
1995brave wrote:
I use Channel Vision splitters. P/N HS-2 for two way. They are 5Mhz to 1Ghz all ports DC passing.


MEH.

That is nothing more than another PASSIVE splitter.

HERE



There is nothing "special" or "better" with that brand.

It has the SAME loss as any other PASSIVE 2 way splitter..

"Insertion loss: = 3.5dB
Max insertion loss @ 1GHz = 4.5dB"


EVERY "PASSIVE" splitter uses nothing more than RESISTORS inside. 2Way passive splitters use 75 ohm resistors, a 3way with use 75 ohm on one port and another 75 ohm resistor feeds two more 75 ohm resistors for the second and third port.

Unless it is a specialty splitter designed to block DC they will all pass DC.

for the record, 3DB IS HALF the signal so 3.5 DB loss per port is MORE THAN HALF of your signal lost..

For the OP, there is a good chance that you may have a 3Way splitter, with those one port may have 3.5DB loss and the other two will have 7DB loss.. Your back TV may be on that 7DB loss..

However, typically when on cable, there is PLENTY of signal typically to get over that loss.

The only way to diagnose is to bypass the RV wiring temporarily by running a coax directly from the park connection to your back TV and retrying the scan..

If it works then you have a signal loss issue, that could be in your RV or it could be the campgrounds.. In most campgrounds they feed the cable hookup via multiport splitters, you could have a bad splitter on the park side of things.. I have run into this.

To check that connect your RV to a different campsite port and see if that helps..

If a different campsite hookup works better than have the campground replace their splitter at your site.

If it doesn't help, then you may need to find your splitter to see if you have a three way in there..

1995brave
Explorer II
Explorer II
I use Channel Vision splitters. P/N HS-2 for two way. They are 5Mhz to 1Ghz all ports DC passing.