RF Antena distribution- Headend equilazation

RF Antenna distribution- Headend equilazation

OK, guys, where is the best place to do headend equalization?

Attic - near antenna
Before distribution AMP

The system will have a Mast mounted amp fed from an attic injector.

Because signal strengths are all over the place, I was thinking about doing headend equlization over about 8 bands of UHF and 2 of VHF.

Most stations are UHF, but 2 are VHF stations. Rotor will have power and signal via a dedicated RG-6 feed. The Antenna has a single downlead. Antenna will be this one: **broken link removed**

I forget the model of the AMP. I think it's the AP-8700 with specs of: The Winegard AP-8700's specs are as follows: • Gain: VHF 17dB / UHF 19 dB • Noise: VHF 2.8 dB / UHF 2.8 dB

To do the equalization, I will have to separate the UHF/VHF and recombine after the equalization. Those would result in a 0.5 db loss when separating and a 0.5 db loss when combining again.
I would have the opportunity to attenuate the UHF or VHF separately in case of overloads.

There would be about 50' of RG-6 before it hits the headend distribution. Currently there are three 4-way taps for the distribution.

I do now have the means of measuring the signal strengths and the tap losses. Currently there is also a tilt compensator at the input of the distribution amp.

So, where is the best place to level the RF?
Attic? The temperatures would be a bit high, but it looks like the right place to put it.
Basement? Just before distribution?

I think the best spot will be the attic.

Predicted values of Noise Margin, are:


The present setup, which is a real zoo, I cannot receive 12 or 17 at all an who knows why. Also not sure what single edge and double edge refraction means in terms of reception. It could mean that double edge is more weather sensitive?

If anybody can answer what effect tilt has on UHF/VHF signal reception, I'd be grateful.

There will be antenna sensitivities and coax vs frequency attenuations as well, so higher frequencies will get attenuated more in distribution.

I'm aware it, an entire non-linear mess and am prepared that there will be lots of engineering to distribute this right. I may have to change some taps as well once I figure out what I have and what I need.


NM: This is the predicted Noise Margin (NM) of each channel "in the air" at your location, specified in dB. You must add/subtract any gains/losses you get from your antenna, building penetration, amps, cables, splitters, and other factors present in your situation. Hypothetically speaking, you need to end up with an NM value above 0 in order to pick up a station.

You don't want to do slope equilization at antenna as the equilizing circuit degrades noise figure very much and usually also screws up the termination impedances.

Where you do it down stream depends on your particular intermod situation. The Winegard AP-8700 is not a very good amp from an IM perspective. It is likely where you are losing it. I would suggest you dump the mask mount preamp and instead go for a better large signal handling distribution amp indoors before you split. Get an amp with only the gain you need to overcome cable loss. More gain means more intermod. I have never seen a broadband mask mount amp work out unless you totally live way out in the country miles away from all TV and FM stations. They generally get creamed by intermod.

I assume you are receiving only HD ATSC signals. The power required for ATSC is much lower then old analog therefore generally creating less IM within the amp. One thing that ATSC is very vunerable to is multipath reception ('ghosting' in old analog TV) so be aware of any reflection situations to the the channel you want. Antenna pointing and front to back ratio of antenna is critical to multipath.

I have generally not seen too much need for slope comp'ing in a residential setup unless you are running over 200 feet of cable. Make sure you use a good grade of 2 GHz RG6 cable, double or quad shielded with solid copper core innerconductor. If you really need slope comp'g the best way is to get a distribution amp that has it within it. Within the distribution amp stages is the best way to deal with the mismatch it causes because the distribution amp will generally isolate the mismatch to amps input and output terminals.

Here is my distribution AMP: http://www.tinlee.com/TV_Signal_Distribution.php?active=5 The VA54-B.

I'm using RG-6 Quad, but it isn't solid copper. But it was free from a Satellite TV business.

I'm 30-42 miles from the transmitters.

The 8200U antenna fell, so it's not up there yet. For the time, it was up there, it did pretty well. The current hodge podge is pointing into a huge tree. I have to finish coming up with the guy wire/turn buckles and make some stud changes to get the support bearing to work and enlist the help of a friend.

The slope compensation, I used was a passive device just before distribution.

You loose HALF your power by putting the antenna in the attic. Been there done that. We had tornados almost every day in the spring I was determined not to have my antenna outside. For 2 years I experimented with my antennas, they worked but not good. I tried several different antenna designs. I tried several antennas connected together in parallel. It all worked but not good.

Finally I put my antenna outside on a 20 ft tower made from two 10 ft sections of chain link fence rail. My stations are all between 295 and 321 degrees magnet. My antenna isset at 308 it picks up 13 degrees both sides of center. I can pick up most of the stations with a tiny antenna but I get a lot of fade, I loose all the channels for 45 minutes with the sun on on the horizon, no TV at all during a hard rain or snow or high wind. A 4 bay bow tie antenna worked great 98% of the time and picks up all channels 40 miles away but no signal during a very hard rain. Next I put up an 8 bay bow tie antenna now I pick up all channels even during a hard rain. 8 bay is over kill but is solved the rain problem. I put up a second antenna for another TV located in the bedroom. I am picking up 44 channels 8 movie channels, weather channel, NPT and more. It is great. If you buy an 8 bay bow tie antenna like the Channel Master 4228 on ebay for $65 you will need to make a few changes for it to work the best it can work. The cross over wires need to be at least 1" apart. Buy some fence wire to make a 48"x48" reflector screen for the back reception will double. Buy 5 antenna matching transformers try them all ONE will work better than any of the other 4. Swat the wires on the antenna machine transformers one way always works better than the other way. Use one section of coax with no splices. If your antenna is 150 ft from the TV one 150 ft long coax works better than two 75 ft coax wires connected together. I built my own antennas I was selling the plans on ebay for a while.

Go to **broken link removed** type in your address click enter. It will tell you where all your stations are the the power of each station.

https://i67.photobucket.com/albums/h292/mikeweaver/Ant-02.jpg

https://i67.photobucket.com/albums/h292/mikeweaver/Ant-01-1.jpg

https://i43.photobucket.com/albums/e358/gary350/004.jpg

Antenna is not in the attic. I need UHF AND VHF unfortunately.

I dont care much about HDTV, just locations. There isn't an HDTV in the house. All use the DigitalStream HDTV converter.

There were two antenna locations on the house. Both were eve mounts on the sides of the house. One eve, sees a huge Oak tree, the other is clear of the tree. They worked pretty well until HDTV came along. I used an old mast that split. The mount is now Unistrut and pipe clamps with a 3' section to guy to and the roof to guy too with a bearing support.
I need to order a few parts and check the rotor an bearing. I need longer studs in the bearing support and rotor. I also need to order the guying system and I won't use metal guy wires.

I was considering one of these: **broken link removed**

but I don't know if I should put it in the attic or the basement.

I had a really nice system until HDTV came along. I had a VCR in my shop that I could broadcast on Channel 4 throughout the house.

I really don't want to describe what I'm using for an antenna now. I have a nice UHF antenna that's pointing into a tree. It used to be on the side of the house that wasn't pointing into the tree. Not good AT all. Both UHF and VHF are slightly amplified separately.

The feed is also foam twinlead to the basement. A real mess. A system that has roughly been in place for 45 years.

It was what I could cobble together. One TV feed in the house needs to be upgraded from dual twinlead to single coax.

I suspect that another location will be added, but not sure.

I watch most of what I want to, using a slingbox and my laptop. The other main use of watching TV is the news in the two kitchens. I also tend to watch the shows online.

TV is almost all UHF now, there are only a few channels below 14 that are VHF. The channels are 2 to 50. Channel 5 Nashville TN transmits 2 different channel 5 stations. I have 50 foot tall trees between me and all 44 stations and the trees are NOT a problem. If you still have one of those old analog TV antennas, get rid of it that is stone age technology. A good CM 4228 antenna will pick up all the channels.

Go to the HDTV Forum and talk to the guys about this. https://www.highdefforum.com/

Go to **broken link removed** to see if there are any VHF channels in your area. A new antenna will pick up the signal better than those old out dated antennas even the VHF signal.

You can buy 75 ohm coax cable at Lowe's and Home Depot cut to the exact length you need from your antenna to your TV. Make your own cable.

You will be surprised how well this will work. If you do every thing you can to prevent lost signal you can pick up TV stations over 100 miles away. Excellent reception is up to about 65 miles.

It does no good to try an pickup signals 100 miles away because all the stations have re-transmitted signals, NBC, ABC, CBS, NPT, CNN, Discovery, and more. All the stations except for local stuff is all the same stations. I can pick up stations from Dickson, Clarksville, and some times Knoxville they are all the same programming as Nashville.

I tried an AMP, it turns out the 8 bay antenna works better than the 4 bay antenna with the AMP. Lost signal prevention is the key to good signal strength.

gary:

The 1st post is the result from TV fool. All real and not virtual. I said I was 30-42 miles from the transmitters. This tree is easily 70' tall and 50+ years old. I realize that the mast mounted amp is the best way to go to cut the losses getting to the distribution system. It did make a difference. Making cables is no big deal. Now I use compression connectors.