King Jack antenna rotator

[dcheatwood]

Well. 2 years into this 2018 class c Forester, with king jack antenna. Watched several videos about the Jack and they all show signal strength LED lights on the rotator panel. Mine didn't have the LEDs. I decided to look closer and saw that there were several little dimples under a sticker. I peeked the sticker back and "whahlah!" There were several little holes just like the video showed.
Turned tv on and could not get any LEDs to come on.
Pulled the panel and nothing but empty space. No wiring, lights nor LEDs.
Have any of you experienced this? Are the signal strength LEDs optional? Should I have them? Weird, to say the least. Pictures in first comment.

[dcheatwood]

What I found.

[Trksr]

Yes, they are optional. My old tt had them, my new class c didn’t.
I bit the bullet and ordered a new one that had them. I was going to change the cover but ended up replacing the entire unit.

Found out it is just as easy to use the bars on the tv. They do the same thing as the leds.

[NXR]

Originally Posted by Trksr

Found out it is just as easy to use the bars on the tv. They do the same thing as the leds.

Agreed. I have them and also have an RF background (radio frequency). The problem with the LEDs on the antenna itself is that there is an astonishingly wide variety of actual frequencies in use plus by TV stations and the fact that there is no way to select which channel the LEDs pertain to. They seem to give the strongest TV signal, which may not be the one you want to watch if the TV stations are in different directions from your location.

They're usually s good starting point but that may be it.

Ray

[dcheatwood]

My last fiver had on-tv signals but the forester doesn't.

Originally Posted by Trksr

Yes, they are optional. My old tt had them, my new class c didn’t.
I bit the bullet and ordered a new one that had them. I was going to change the cover but ended up replacing the entire unit.

Found out it is just as easy to use the bars on the tv. They do the same thing as the leds.

[dcheatwood]

Interesting. Thanks for input.

Originally Posted by NXR

Agreed. I have them and also have an RF background (radio frequency). The problem with the LEDs on the antenna itself is that there is an astonishingly wide variety of actual frequencies in use plus by TV stations and the fact that there is no way to select which channel the LEDs pertain to. They seem to give the strongest TV signal, which may not be the one you want to watch if the TV stations are in different directions from your location.

They're usually s good starting point but that may be it.

Ray

[PETEWOOLF]

I have a app on my phone that points to the tv station

[NXR]

Originally Posted by PETEWOOLF

I have a app on my phone that points to the tv station

Does it use your phone's GPS location and built-in compass functions or is that part all manual? If it uses one of those or both, please give its name.

I looked at several but the ones I found would not even use our GPS location, which left us semi-guessing as to where we were in a location we'd never been to before. I could not derive much value from those.

I also have a disconnect between where the arrow on the KingJack knob points and where the antenna itself seems to be pointed. I used to work in the broadcast industry as an engineer in this area a long time ago (our home area) so I know where most of the physical locations are for the transmitters, which is between NE and ENE.

Yet I have to point the antenna slightly south of due east to bring in the weaker stations. The masses of metal on the roof called "air conditioners" could be affecting the antenna pattern a bit.

My biggest deficiency seems to be the qwappy splitter that FR installed, which is used by both the cable and antenna inputs. I dug it out and it has more loss than I would expect. Moving the cables around made a difference on some of the TVs in a weak signal area we were in. I need to chase the cables and mark which one goes where.

At one campground where we're at for a month all three of the TVs were very snowy on their analog cable system. The staff brought out a battery-powered TV and connected it directly to the cable outlet on the pedestal. It was crystal clear. So I ran one of my cable TV extension cables in a bedroom window and connected it directly to the bedroom TV and to the pedestal and the picture was crystal-clear.

I have a hand-held device called a spectrum analyzer I brought along with us on the trip. The signal coming out of the pedestal was reduced by 10db, or reduced to one-tenth of its strength, by the time it got to the front TV. That is a lot of loss for such a short distance so something is wrong somewhere.

No, turning the TV antenna preamplifier off does not help when using cable. We have the MovieVision VCS-3 switching box so the preamplifiier is not in the signal path when the box is set to "Cable".

Ray

[CedarCreekWoody]

I use DTV Antenna app which points toward the signal. I've found it very useful.

[NXR]

I decided to do some Googling around and found the attached images. This looks like the wall plate we have for our amplified King Jack antenna up on the roof. I know there is nothing connected to the front jack so FR must just be using the rear jacks. That means this plate has a splitter built inside it, which will be causing some signal loss. I'll need to remove it from the compartment wall when we get the motorhome back and see exactly how it's connected.

Using multiple splitters will degrade the signal strengths even more. This article shows why the loss occurs: https://support.channelmaster.com/hc...2HD-CM-3213HD-

FYI, when you look at a splitter it usually has a few markings on it saying how much loss each jack has.

3.5 db means the original signal strength is cut in half.

7.0 db means it's cut in half again. See the above linked article for how a four-jack splitter is actually two splitters internally.

So if the incoming signal is "1" then the signal strength coming out of the 3.5 db jack is slightly less than "0.5" and the signal strength coming out of the 7.0 db jack is cut in half again so it will be slightly less than "0.25"

A 10 db loss as I mentioned earlier is a reduction of ten times or "1" to "0.1" of the original signal strength.

So if FR is using the splitter on the back of the antenna's wall power injector plate (its technical name) that means the signal strength going to the MovieVision switch would be cut at least in half. Then the splitter connected to the MovieVision switch would cut it in half again for one TV (the 3.5 db jack) but cut it in half twice (the two 7.0 db jacks) for the other two TVs.

King Jack Power Injector Wall Panel 3.5 db loss (I cannot find a spec sheet though) ->
MovieVision VCS-3 switch ->
Four way splitter has either another 3.5 db loss or 7.0 db loss

So I'm betting this is why my spectrum analyzer is showing a 10 db loss (3.5 db plus 7.0 db)

But I won't know for certain until I get it all mapped out in a few weeks.

My gut feeling is that the jack on back of the wall power injector plate for the second TV ("SET 2)" may be 7.0 db, though. We'll see...

If SET 2 actually is 7 db then a simple over-the-air TV improvement could be to move the cable from the SET 2 jack behind the wall to the jack on the front of the wall plat.

Ray

[U.S.ArmyVeteran]

Free from your Gubment:-)


https://www.fcc.gov/media/engineering/dtvmaps

[Larry-NC]

Originally Posted by NXR

At one campground where we're at for a month all three of the TVs were very snowy on their analog cable system. The staff brought out a battery-powered TV and connected it directly to the cable outlet on the pedestal. It was crystal clear. So I ran one of my cable TV extension cables in a bedroom window and connected it directly to the bedroom TV and to the pedestal and the picture was crystal-clear.

People have reported that the F-connectors in their RVs have been applied very poorly. Might want to redo all yours first, before swapping out the splitters.

Originally Posted by NXR

Yet I have to point the antenna slightly south of due east to bring in the weaker stations. The masses of metal on the roof called "air conditioners" could be affecting the antenna pattern a bit.
...
I have a hand-held device called a spectrum analyzer I brought along with us on the trip. The signal coming out of the pedestal was reduced by 10db, or reduced to one-tenth of its strength, by the time it got to the front TV. That is a lot of loss for such a short distance so something is wrong somewhere.

I am jealous. The antenna farm in my home area is 18 miles ESE of here. Directly in line, across the street from me is a granite outcropping at least three stories high. It is higher than my high-VHF + UHF Yagi antenna on a 10 foot mast on the roof.

One mile away from me, due east, is a 10-story skyscraper. Trying to position the antenna for the signal without the almost-equal-amplitude multipath is a nightmare. I actually borrowed a portable (not handheld) spectrum analyzer and took it onto the roof while trying to find the sweet spots. What I ultimately found was that although the antennas of four stations were pretty tightly clustered in less than a mile, The sweet spot for each one differed. No way to use the antenna without a rotator. The trick seemed to be keeping the antenna somewhere in the primary lobe while keeping the multipath out of the first secondary lobe.

[NXR]

Originally Posted by U.S.ArmyVeteran

Free from your Gubment:-)

https://www.fcc.gov/media/engineering/dtvmaps

Whoa! That is exactly what I'm looking for.

Thanks!

Ray

[NXR]

Originally Posted by Larry-NC

What I ultimately found was that although the antennas of four stations were pretty tightly clustered in less than a mile, The sweet spot for each one differed. No way to use the antenna without a rotator. The trick seemed to be keeping the antenna somewhere in the primary lobe while keeping the multipath out of the first secondary lobe.

If there is sufficient strength, you could try removing a director element or two on the house antenna. Those are the elements at the front of the antenna. They narrow the focus of the antenna so removing one or two could open the main lobe up enough to compensate for the reduction in strength that also will occur (because the antenna is less focused). That would increase the multipath strength but I'm thinking that will not negatively affect reception.

I have two of these, one is the 6G Combo model covering 15 MHz to 6 GHz and another one for 50 KHz to 960 MHz, the WSUB1G+ model

https://j3.rf-explorer.com/

https://www.amazon.com/Studio-Explor...7323737&sr=8-6

https://www.amazon.com/72-12855-Expl...323874&sr=8-54

Ray

[Larry-NC]

Originally Posted by NXR

If there is sufficient strength, you could try removing a director element or two on the house antenna. Those are the elements at the front of the antenna. They narrow the focus of the antenna so removing one or two could open the main lobe up enough to compensate for the reduction in strength that also will occur (because the antenna is less focused). That would increase the multipath strength but I'm thinking that will not negatively affect reception.

I have two of these, one is the 6G Combo model covering 15 MHz to 6 GHz and another one for 50 KHz to 960 MHz, the WSUB1G+ model

https://j3.rf-explorer.com/

https://www.amazon.com/Studio-Explor...7323737&sr=8-6

https://www.amazon.com/72-12855-Expl...323874&sr=8-54

Ray

Thanks for the suggestion, Ray.

We (Raleigh, NC) were the first area in the country to broadcast HDTV, back in 1996. And I was an early adopter. The tuners then were not as sophisticated as they are now. Currently digital signal processing is used not just to cancel multipath, but to detect it, delay the primary signal appropriately, and add the two for maximum SNR.

The multipath signal seemed to have similar amplitude to the direct signal. Before the cutover to HDTV, the ghost was just as visible as the original image on the analog TV sets. Anything that would reduce the directionality of the antenna would hurt, I think.

The way I used the spectrum analyzer was in a "accumulate maximun values" mode--I forget the correct term. If you set it so a single channel covered most of the screen, after a few seconds you would get a signal that looked like two tails with a plateau in between. The plateau was perfectly flat except for a little peak for the pilot signal, right at the lower band edge. That's with optimal reception.

What I would get with multipath was a dip in the center or a plateau that slanted in either direction, corresponding to the specific frequencies where there was destructive interference.

The whole question is kind of moot now. DW then was a TV addict and wanted reasonable performance. She passed away in 2005. DW now never watches OTA TV. It's strictly Over-The-Top for her. The ancient DTV tuner hasn't been used in a decade. Since this is a high-tech area, we have at least four providers of high-speed broadband--and they are competitive.

[NXR]

Originally Posted by Larry-NC

The multipath signal seemed to have similar amplitude to the direct signal. Before the cutover to HDTV, the ghost was just as visible as the original image on the analog TV sets.

This should go on the list of things people born this century have never seen. TV ghosts.

Ray

[Bob2019]

This is the worst reception antenna I have ever had on a RV. I live within 10 miles of the TV stations and get ½ the stations with the King Jack. If I disconnect the the KJ and hook up rabbit ears, I get over 35 stations. Going out another 10 miles West, I can't get a thing, but can with the rabbit ears. To me, I wish my RV came with the bat wing antenna. Now that worked in many places i've been. The King Jack is a total waste to put on a RV.

[Jay2504]

Is it possible that the problem is not the king antenna but all the splitters it has to go through? When the “rabbit ears” were hooked up, was it directly to the tv? After reading this thread, I am going to check my system out to see if I can eliminate any splitters like maybe the one going to the unused bedroom tv antenna jack. Jay

[Bob2019]

Yes, the rabbit ears were hooked up directly to the TV. I also carry one of those thin flat sheet antennas and laying it against the over cab window gets some stations in an area where the King Jack get absolutely nothing, and remember, the King Jack is an amplified antenna also!

[NXR]

Originally Posted by Bob2019

Yes, the rabbit ears were hooked up directly to the TV. I also carry one of those thin flat sheet antennas and laying it against the over cab window gets some stations in an area where the King Jack get absolutely nothing, and remember, the King Jack is an amplified antenna also!

Do you have that wall plate I attached a picture of? You should. In case you did not know, it has a small pushbutton on it that turns the antenna amplifier on. When the button is pressed in there is a light that illuminates on that plate.

Do you have the MovieVision switch? Is it in the TV ANTENNA position?

Where precisely are you connecting the rabbit ears? Into a MovieVision switch, directly into a TV or what?

We're at least thirty miles from the nearest TV transmitter and have good reception in our driveway.

Ray