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Jim & Susan 08-02-2007 07:09 PM

HDTV and old Airstreams
 
2 Attachment(s)
I’ve just about completed the restoration of my 35 year old antenna and had a couple of observations and questions for everybody. First, let me dispel a bad myth. This antenna picks up High Definition T.V. just fine. There is no reason under the sun to go out and buy a special T.V. antenna just to pick up HD. We bought a 19” HD flat screen to use in the Airstream when it’s finally ready to go camping. I took it out there today and had it auto up to the local stations, man what a picture! This will be the only combination we’ll ever need for video (well, plus the portable DVD player).

And just so everybody knows, Susan says that this arrangement is for rainy days ONLY!

I’ll have couple of questions in a few minutes. But here’s a couple of pics.

Jim

Jim & Susan 08-02-2007 07:26 PM

3 Attachment(s)
Everybody probably knows that in these older model Airstreams, the cable from the antenna runs from the back of the antenna, through a hole in the roof, down the side of the camper to a small “amplifier”. The cable and the amp are long since worn out, so I had to replace them. Along with the gears at the base of the antenna and the inside handle (these parts are still available, can you believe it?).

Jim & Susan 08-02-2007 07:44 PM

The OEM cable was that flat stuff that we all remember from the ‘60’s (can you say rabbit ears?!). I bought an indoor/outdoor 75 to 300 ohm matching transformer to attach to the antenna and 25 feet of RG-6 cable to run back inside.

SO GET TO THE QUESTION ALREADY, would ya?

When shopping for the RG-6, the only exterior grade I could find came with a ground wire that you are supposed to tie to the ant on one end and earth ground on the other. So, how do we properly ground the antenna? Presumably, the antenna itself is grounded thru the body of the camper. But, how do you ground the wire? The exterior grade wire specifically stated on the package NOT to use it inside the walls. I assume that is because of the ground wire (lightening heats up the ground and instant fire in the walls?). There is a ground “block” that you can buy to use on your house. Cable from the cable company or dish goes on one of this block, cable going into the house goes on the other, then the block is grounded to earth ground (this is made to be mounted on the outside of your house).

Do you think I could get away with mounting one of these inside the camper on the aluminum wall? Should I try to mount it somewhere on the roof? That could get messy. Anybody else dealt with this before? Tell me how you did it. Tell me how it’s done on the newer camper.

Jim

Sugarfoot 08-02-2007 10:20 PM

I'd like to know this as well. I still have the old 1960 flat cable with an antenna I must piece together with cable ties for each use. But I also had a coax cable run along the same route as the flat for spots where TV hookups are available. Am I also at risk regarding grounding?

I'm glad you debunked the the HDTV myth. But this brings up another question. When everything goes digital, no more analog signals, will these older style antennas work? I'm totally in the dark on how all this works.

2airishuman 08-02-2007 10:38 PM

i'm sure a video/broadcast techie will clear this up.

until then....

any vhf/uhf antenna can pick up a digital signal...

all/most lcd teles convert analog signals to digital b4 displaying the moving pictures...

so regardless of antenna signal (analog or digital or hd) the image IS digital.

you don't mention what model tele or the 'hd' resolution...720 or 1080?

19 lcds usually have a native pixel resolution of 1400/1000...

i'm not sure this is a big enough screen/resolution to appreciate fully the true HD digital broadcasts...

for example,

i'm using a 42 inch projection lcd and the cable hd image (full hd/decoder) is clearly different.

however when i plug in the 19 inch hd lcd the screen parameters limit seeing any difference...

still a 19 inch lcd digital image is mighty fine.

adding to this confusion, many 'hd' broadcast signals aren't truely at the HD resolution...

it all gets very confusing when ya read about it...

are u receiving a digital signal or a high def digital signal?

cheers
2air'

volvophile 08-03-2007 05:11 AM

I use rabit ears for both of my digital sets. One I bought just for the digital tuner, and the other I had in the garrage for 10 years or more.
As far as I can tell, the only difference between the two was the sticker on the box that said "hdtv ready!"

overlander63 08-03-2007 05:19 AM

Our new antenna came with the 75 ohm cable, and I was able to pull ot through the walls.If you haven't noticed, the cable guys will make a loop of cable near the entrance to the home. It the cable is struck by lightning, the loop is supposed to "sling" off the lightning before it enters the home. (it doesn't work, ask me how I know) Is there anything that says why it can't be used indoors?

Jim & Susan 08-03-2007 05:54 AM

Terry, there was no explanation as to why it can't be used inside a wall. I'm assuming that the ground wire, if hit by lightning, logically would heat up--to extreme temps and cause a fire inside the wall. The ground wire is attached to the outside of the RG-6 cable, but is a separate cable altogether.

Jim

HiHoAgRV 08-03-2007 08:09 AM

I installed a Sanyo 15" HDTV flat screen last night and the Wineguard amplified batwing works fine also.

Jim & Susan 08-03-2007 09:48 AM

Just to separate out a couple of things.

The antenna on the roof is one of the old Braund log periodic models. I’ll have to look up the model number later. I don’t have it with me at the moment. It was originally made to pick up broadcast channels #2 to #13. In other words plain old VHF standard definition (or, some call it analog) T.V. signals. “Old fashioned” T.V. for us old guys. UHF channels 14 thru 80(?) were something fairly new in 1972 when this Airstream was built.

The T.V. itself is a Polaroid true 1080i resolution 19’” LCD flat screen. Sorry, I don’t have the rest of the specs with me at the moment. And the resolution is fabulous, even on such a small screen. In the broadcast T.V. world (i.e. not CATV or Satellite T.V.) there are two types of signals broadcast over the airwaves; Standard Definition or High Definition. Standard Definition is the stuff we’ve been watching since T.V. was invented way back when. High Def is the new stuff.

A few words about CATV. Many (not all) CATV companies actually bring a digital signal to your home. Don’t confuse the “digital signal” provided by the CATV company with High Definition T.V. Old fashioned CATV signal was analog, the newer stuff is digital all the way from the source to the set-top box on top of your T.V. Why is this? Signal ingress. Analog CATV is much more prone to stray (or intentional) signals interfering with the signal the CATV is trying to deliver inside your home. Think Ghost Signals from a broadcast station on channel 2 bleeding into your cable and messing up the CATV signal on CATV channel 2. Here in Atlanta, broadcast channel 2 is the local ABC affiliate and channel 2 has an incredibly strong signal. My local CATV company, Charter, puts the local PBS affiliate on the cable at channel 2. Since Charter doesn’t provide a “digital signal” all the way to the box on my T.V., broadcast channel 2 bleeds over into CATV channel 2 and screws up the signal. This is one reason that CATV companies are using digital signals all the way to your T.V. and why over the last few years, your Cable looks so much better. Does all this make sense?

Now, as to the T.V. itself. When I initially connected the tele up out in the Airstream last night, I told it to “auto detect” all the broadcast signals it could find around the area. The picture was terrible! What I forgot to do was to set the auto detect for “off-air” as opposed “CATV” mode. SO the TV was attempting to find CATV-like signals instead of broadcast T.V signals. Once I changed it to “off-air” and performed the auto detect again, the channels all came in beautifully in both analog and HDTV.

Back to the “off-air” or “broadcast T.V. thing for a minute. Eventually, the standard definition broadcast T.V. will go away and all broadcast T.V. will be High Definition. There are supposedly converters in the works that will take that HD broadcast signal and turn into an analog signal that your current standard definition T.V. can use. So, not to worry just yet.

I hope this is as clear as mud to everybody.

Jim

Sugarfoot 08-03-2007 09:50 AM

Thanks everyone for clarifying the antenna~digital signal thing.

Jim & Susan, I know you're doing a restoration and the situation is different from mine, but are getting your signal through a dish or through cable hookups available at campgrounds? I'm wondering if cable at campgrounds would be already grounded at the hookup.

Jim & Susan 08-03-2007 09:56 AM

We haven't actually been camping in the Airstream yet, and it is our first RV of any kind. So I don't know how it's done in the campgrounds. My guess is that some are and some aren't grounded. From what I'm readin/hearing, they should be.

So, can somebody with a newer model AS take alook at their setup and see if they can locate a ground on the antenna/wire combo?

Jim

Chuck 08-03-2007 10:04 AM

I believe that "loop" in the wire is there to help shed water, and keep it away from nearby connections/entry points...not "sling" lightning. Surface tension causes the water to flow down the wire...when it hits that loop, it sticks to the wire until it hits the low spot, where it falls off.
If its hit by lightning, the wire in the cable is going to heat up (maybe even to the point of melting) whether its grounded or not. The ground wire just helps give it a clear path to ground, which "might" help keep it from electrifying everything around it.

I can see where its helpfull in a wooden house, (where an external ground wire is connected to the house's grounding rod), but in a metal trailer, any lightning that hits the wire or antenna is going to arc to the body of the trailer, anyway, and find another ground. (umbilical, if you're plugged into shore power, or the jacks, if they're touching the ground....otherwise, you don't have a "ground".)


have you checked that skyliner to make sure it isn't leaking? The pot-metal base deteriorates, and can form tiny pinholes that let the water right through. not to mention the corrosion on the skin of the trailer, from the dissimilar metal contact....
I was able to find replacement gears and such...but what I couldn't find was any of the other innards that were rusted solid on mine, from so many years of leaking down the shaft. no way to get it apart and replace the o-rings in there, so I scrapped the project and went w/ a new batwing. If the skyliner isn't leaking now, it is bound to, eventually.

vswingfield 08-03-2007 10:11 AM

“HDTV” Antennas
 
I have a Mitsubishi 37” 1080p LCD in my Excella. The old Braund on it works great for true HD local stations. I have a Dish 622 DVR. It is a 1080i unit, but right now my local stations from the bird in the sky are not HD. The 622 records from the antenna just fine. I watch all my local channels in HD via the antenna and the Dish programming via the dish. Can’t tell the difference. The thing is, the antenna doesn’t really care what the signal is.

Vaughan

Jim & Susan 08-03-2007 10:19 AM

Or the loop could be there for strain relief to keep the tension off the connectors to some degree.

As to the ground block, the exterior grade RG-6 was apparently made to be used in conjuction with the ground block in a static installation, like the side of your house. I also got the impression that the ground block had something internal that would shunt an electrical overload to ground if needed and keep it off the dielectric and ground shealth on the house side of th equation. BUT, I need to look into this further.

At some point, a PO completely covered the mount, except for the moving parts, of course, with Vulkem. It looks rough, but hey it's on the roof. And the shaft did leak a couple of times, but I replaced a couple of O-rings during this rebuild. I'll just have to see how it goes.

Jim

FreshAir 08-03-2007 10:35 AM

Our PO handed me the original antenna to our '66. It used to mount on the front of the coach near the front window. I 'patched' the 2 mount holes with chrome tape. The antenna is in good condition except for the old flat wire. I have been considering remounting it (it folds up vertically) because it does look vintage. Any opinions or experiences pro or con?

Neil and Lynn

Jim & Susan 08-03-2007 11:11 AM

The vintage look is one of the reasons that I restored mine. We wanted to have a TV antenna of some sort. Truth be told, I've only spent about $30 to $40 to on the antenna itself. The wire needed to be replaced either way (buy new or restore old). We decided to keep the exterior as "vintage" as possible, without breaking the bank. The interior we intend to modernize and build to suite us. That's kinda the way we see it anyway.

Jim

ROBERTSUNRUS 08-03-2007 11:06 PM

Quote:

Originally Posted by anholman
Our PO handed me the original antenna to our '66. It used to mount on the front of the coach near the front window. I 'patched' the 2 mount holes with chrome tape. The antenna is in good condition except for the old flat wire. I have been considering remounting it (it folds up vertically) because it does look vintage. Any opinions or experiences pro or con?

Neil and Lynn

:) Hi, Neil. I would put it on just for the looks, [original antenna] even if it doesn't work. And if it does work, that's even better.

Happycampers 08-04-2007 05:45 AM

I was told you only need to hook up the ground if you are getting interferance. So this is one of those things, if you ask 10 different people you will get 10 different answers. I would call a cable Co.

nickcrowhurst 08-04-2007 12:26 PM

On my Skyliner antenna the loop in the cable is necessary as slack to enable the whole antenna to be rotated through almost 360 degrees via the internal handle. When rotated in one direction, the cable is wrapped around the perimeter of the rather large base.
Nick.


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