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What are motorhome users doing?

post #1 of 19
Thread Starter 
How are you guys hooking up your CECBs inside? Do I need to look at a particular brand of CECBs that tend to work well in this situation? I have two CRT televisions in my Holiday Rambler Endeavor. The one in the front is wired with a VCR. That signal can also be redirected to the rear television. I'm not sure how the antenna is hooked up though.
post #2 of 19
I should imagine it would be just like a house - put the CECB on the antenna, run a coax from the CECB ant out to whereever the antenna went to before, scan put old receiver on channel 3 and and you're receiving DTV.
post #3 of 19
Originally Posted by ChuckZ View Post

How are you guys hooking up your CECBs inside? Do I need to look at a particular brand of CECBs that tend to work well in this situation?

No. The same criteria apply to all units, assuming you have access to 120v AC. See the 'Best & Worst' topic at the top of the forum for details.

The existing antenna connects to the CECB, which connects to your TV or VCR.
post #4 of 19
There are a number of boxes that have external supplies (Wall-Warts/Power-Bricks) that can be used with a cigarette lighter plug converter. If you have a 12-Volt TV already, you may be referring to this aspect.

Look for "E" for External
Cigarette Lighter Plug Example

And yes, you can run an antenna rotor on 12-Volts (LOL), but thats a bit extreme.

Choose an omni-directional antenna for the roof, make up the difference you loose by not being directional by using amplification.

Most mast mount antenna preamps are negative ground too.
I run a Channel Master CM-7777 mast mount preamp on 12-Volts when the power is out here. It runs on a bit more DC usually, so it is slightly decreased in gain. Note that it will run from 6.8-Volts and up. So using a variable voltage supply is an available option.
This is a fair option if your a good distance from any transmitters.

The small tubular bullet style with a 10-Db gain are also 12-Volt negative ground and are usually enough if your near a city.

Then there are "Active" omni-directional antenna's that combine to two. The problem there is when you move your camper near any transmitter you don't have the ability to remove a preamp from the circuit path. A non amplified omni-directional antenna with a short run to inside leaves the ability to use a preamp or a cable splice barrel when needed.

Hope this helps somehow.
post #5 of 19
For what it's worth, Camping World (the RV store) sells a Winegard CECB. Their price is a bit high at $59.99. Winegard also has an optional battery pack. My father picked up an identical RCA unit at Target last week for $45. It works very well at holding weak signals, as good as my Zenith DTT-901 and has analog pass through. We experimented in a room with a lot of interference and a cheap(free from Craigslist) Jensen TV631 antenna and the stations picked up showed strong and clear. We also tested a Sansonic(no analog pass through) which uses an external power supply as well, and it was terrible at holding poor signals. Almost all stations were unwatchable. That said, I'm using that same Sansonic at my home with a bedroom TV and it works great, picking up one more station than my Zenith. My home receives strong signals and no interference.
The RCA/Winegard is a nice size and should work well with a variety of signals.
For convenience the RCA's coaxial cable is the push on variety. Very handy for anyone wanting to switch quickly between TV's or hooking up a box in the dark.
post #6 of 19
I am told some people have used the Winegard on 12 vdc even though it is rated lower.
I don't know how safe this is.

I haven't seen a review of the unit on here.

Winegard's equipment in antennas seems very good.
I would be happy to pay this much if I was sure it was a good unit.
For the moment I plan on using the Zinwell for dc use.

You can buy direct from Winegard.
post #7 of 19
The Artec T3AP has an external 12VDC power supply, and with my coupon, I got it for free!
post #8 of 19
I just got it today, I can do some testing later. I'm planning on using it
in my parents RV this summer. Unfortunately, those 12VDC analog TV's
are not as cheap. I thought people would be unloading them like crazy.
post #9 of 19
Ok, just tested it.

It pulls in all the channels my Insignia NS-DXA1-APT does, and to test it, I unplugged my preamp and rescanned, and the only station it missed was the same weak one the Insignia misses.

The menu and EPG look almost identical to the NS-DXA1-APT, with a now/next transparent look, using the same style boxes and fonts, weird. It's also much smaller than the NS-DXA1-APT, but all plastic. Only a power button on the unit, so don't lose that remote!

The power supply is a wall wart made by DVE. It says the output is 12VDC @ 0.5A. Testing with a multimeter shows 11.9VDC output. It has a diagram showing polarity of the plug on the wall wart also, so I see no reason why you couldn't make a power cord for a lighter socket. Here's a link to a similar model power supply made by the same company.

In my short test, I did notice the picture quality looked a bit dark and greenish, but in the menus there are adjustments for hue, contrast and brightness to correct that. A weird "feature" I've never seen before. Also noticed there's a video freeze button that freezes the picture. Another odd feature I can't see using for anything.

I'd give it a thumbs up for mobile 12VDC use I see no reason why it would not work.
post #10 of 19
This is good news.

I started a 12V thread a while back,
but lack of interest in battery power and lack of posts by owners of different brands confirming chassis polarity so I could keep an updated chart in that thread caused it to be abandoned by me and fade into the sunset....

Could you make just one more test with your meter? It would confirm it to be a negative ground unit.

Measure on your lowest ohm's scale from the actual chassis ground with one lead (Threaded RF collor of Ant-In/TV-Out connector would do for a plastic case...),
to the pin or collor of that DC input jack on this model that is marked negative on the wal-mart.

It should be a direct short if negative ground, or count up slowly as your meter's test current charges the electroytic capacitors on the power supply board if positive ground.

Do note that during the 12 years I worked as a marine electronic technician that I've seen my fair share of smoked 12V TV's installed by owners due to the fact that they were positive ground. Where as the 12V VCR's they were connecting to it were negative ground.

Most, if not all 12V VCR's and amplifiers, etc. are negative ground. But don't forget to test the TV too or you'll cause a direct short when you connect any lead that connects the chassis's together like RCA/RF/S-Video cords.
post #11 of 19
I have the older RCA 12V TV and some Panasonic semi-pro vcrs and Alpine automotive vcrs.
Do you have any idea if these have any issues?

I also have a much older Panasonic TV made to operate on D batteries.
I'm not sure about voltage.
I hadn't thought about conflicts between internal ground when using multiple units together.

Has anyone come up with a way to isolate the units?
I can use line out on the newer Panasonic decks, but I think all the TVs have rf only.
I have one very cheap small TV with line in.
post #12 of 19
Originally Posted by THX-1138 View Post

Has anyone come up with a way to isolate the units?

On audio connections you can use a hum-blocker that is used in car audio installations. It is just a 1:1 transformer that decouples the ground loop that causes hum in high powered audio installations.
Google "Ground.Loop.Isolator", They're about $3-$5 ...

On video connections there are limited choices due to the bandwidth needed for baseband RCA video / S-Video. Not to mention the inversion of signal if you tried to just cut the ground (LOL).
Makes a mess of a picture on Baseband/S-Video.
I used to use old IF-Transformers from radar boards that had to much of It's silicon componentry blown to be viable as a board level repair candidate

RF connections can be decoupled by simply connecting to 75-Ohm to 300-Ohm baluns back-to-back.

Just solder, or use two 1/8" screws&nuts to connect the 300-Ohm ends to each other. Then tape or heatshrink the connections.

I would solder, then heatshrink the two connections.
Then solder a 3/8" ring lug to the edge of a piece of tim foil.
I slid the ring lug over one threaded 75-Ohm end and wrap the entire pair to shield it. Then trim the excess making sure to leave a 1/4 gap on the other end without the ring lug.
Finished up with a piece of heatshrink over the whole pair with a popsicle stick or something stiff to unite the pair into one piece.
Lastly, tighten a nut over the end with the ring lug.

Use that shielded end on the negative ground unit of course.

There is a slight loss of course, but it is fine for the channnel 2/3/4 output.

As to your equipment compatibility.

You need to (or have a friend) test the negative supply lead entering all the equipment you'll use in an installation against any chassis-related connections like the casing of RCA audio/video jacks, casings of S-Video jacks, and threaded barrels of RF F-Connector jacks, etc.

Most of what you listed should be fine as they are already made to be used in an American 12-Volt enviroment, and are almost certainly negative ground.

Where people used to get in trouble would be china/taiwan/etc. D-Battery TV's that had wal-warts or power-bricks. They were cheap and they just "assumed" they would work... A penny saved would turn into a dollar burned so to speak.

I'd test that older Panasonic D-Battery TV before I connected it to anything.
post #13 of 19
On the power plug, the sleeve is negative, and in the socket the sleeve does short to the coax collar.

So, when plugged in, 12VDC is zipping all over the circuits, but any exposed metal (only the shield on the connectors) is at 0 VDC.

I'm guessing this is good, if the TV is the same, right?

I just checked my parents RV, and the TV shelf has 1 12VDC plug and
a dual AC socket. It doesn't have an inverter, so I think it might just make sense to run both on AC, unless I can find a 12VDC TV real real cheap.

I'm getting an AC powered 9" color TV for free, but it would be nice to
be able to run it on 12VDC since they do sometimes camp without AC
power, and we all know during crappy weather, it's nice to see what's
happening when the power grid gets zapped by lightning.
post #14 of 19
Originally Posted by oldsyd View Post

I'm guessing this is good, if the TV is the same, right?

Yes, that is negative ground.

Bear in mind that both stores and places like eBay, CraigsList.org, Etc. are flooded with analog (non-atsc) TV's they just want to liquidate because they wont work on the new digital over the air system. They can be had for real cheap.

Just google or eBay/CraigsList for "12.Volt.TV". Add terms like "LCD", "Used", "Open.Box", "Liquidation", Etc. to narrow the results.

I have a nice NTSC+ATSC Haier HLT71 "Open Box" from eBay I paid $7.35 for, under $20 with shipping. Something like that would eliminate the need for the CECB in the first place.
post #15 of 19
Originally Posted by WeThePeople View Post

By that you seem to be indicating that the collar is negative and the pin is positive on that plug.

Can you pull that plug out of that jack a little to expose the collar while maintaining contact with the jacks wiper and measure low ohms to the chassis for a direct short (Indicating negative ground) with the wal-wart unplugged?
The pin on that jack is easy to tag with a meter probe, but the collar wiper can be a bit tight as you know.

Yes, that is what I am indicating. I had already made up an adapter cable with a 5.5mm x 2.5mm plug on one end and a similar jack on the other end, but I didn't connect the wire to the neg terminal of the jack so that I could use clip leads to measure the voltage AND current when connected to the AC adapter. So, it was not necessary to slightly pull out the plug to check to see if the negative terminal was connected to the common terminal of my Audiovox PLV16081 8" LCD DIGITAL TV.
Using my Fluke 25 DMM to measure, the resistance between the negative polarity collar of power connector and the common terminals of the TV (ant shield and RCA shells) is about 0.3 ohms which seems to indicate what you call negative ground.

Have you ever seen a situation where the negative was the collar but the positive was connected to the common terminals? I'm thinking of the early days of PNP transistors that used a positive common terminal.

I'm looking for a 9-Volt CECB to use a 7809 9-Volt regulator IC on. That would work fine on my huge 8D battery bank I already have for my houses 10-KW inverter rack down to 11-Volts or so.

You must read Home Power magazine.

Then there's power outages in house applications.

That's what got me interested. We lost power during a Christmas Eve ice storm.


Do note that during the 12 years I worked as a marine electronic technician that I've seen my fair share of smoked 12V TV's installed by owners due to the fact that they were positive ground. Where as the 12V VCR's they were connecting to it were negative ground.

Have you seen this site?:
post #16 of 19
mrpeter105 gave some useful URLs on the Artec T3A Pro NTIA CECB thread that are on-topic here; he is new to the forum, so I posted them for him:
Originally Posted by mrpeter105 View Post

I have been using a T3A PRO box since about sometime last summer and I am generally satisfied with the unit. Also, some members were wondering about 12v or emergency usage for these units. I found the following webpages that will be of interest. They all feature the T3A Pro and how to hook it up for 12v. The second link even has them hooking it up to 2 lantern batteries and outputting it to one of those handheld tv's.


I too am concerned about receiving the latest emergency news bulletins and need to run on battery power. I was using a small 5" B&W NTSC TV indoors, but my 8" digital TV requires an outdoor antenna. I knew about the first link, but I didn't know about the other two; thanks! I'll post them for you:

http://ezdigitaltv.com/RVs_and_Converter_Boxes.html (WeThePeople already gave this one earlier)



I would like to add this one from their excellent site:

I'm using a small sinewave inverter, the Exeltech XP125, which comes with a cigarette lighter plug which fits the jack on my J900 and ES2500 12volt 17Ah jumper packs.

I also did another post about voltage limits which is on-topic:
post #17 of 19
Thread Starter 
Okay, so I'm thinking of getting two DTVPal Plus boxes. Am I crazy?

Should I have opted for one box and maybe a DVD player with an integrated ATSC tuner?
post #18 of 19
Originally Posted by ChuckZ View Post

Okay, so I'm thinking of getting two DTVPal Plus boxes. Am I crazy?

your family and friends would have to answer that.

Originally Posted by ChuckZ View Post

Should I have opted for one box and maybe a DVD player with an integrated ATSC tuner?

with more than one set a dvd player with tuner might be a good choice because you might not always find OTA signal you want.

the DTVPal has a good feature of a possible long program guide. while away from the home base you might not have other easy program scheduling.
post #19 of 19
The Panasonic DVDR's built-in tuners have excellent PQ - much better than the DTV Pal, IMO. The only CECB I've ever seen that comes closest to equaling it with PQ is the CM through s-video. (In the area of of PQ, though, there is more than just that one CECB which will better the Pal.)

The only things are, the channel changing on the Panny is a bit slower in comparison and there's no guide.

One good thing, though, is that you will be able to time-shift with the recorder using the very versatile DVD-RAM format.

If you're using it on a 4:3 TV, you could use the Pal with the tunerless Panasonic EA-18, because that model has an IR blaster to change the channels on the tuner (probably be more dependable than the Pal's timers, and you'd only have to set the timers on the recorder - not both units).
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