Maximum Length of Coax?

Hillbilly

DTVUSA Jr. Member
#1
I live at the bottom of a large hill, I can only get a weak DTV signal at my house. Yesterday I moved my TV, anttena, converter box, and amplifier (old Channel Master) to the top of the hill. I mounted the anttena on the tractor bucket and raised it about 15 feet. I can get two stations about 60+ miles away (I used to get 3 analog stations with antena on my roof).
I would like to move my antenna to the top of the hill but I would need to run about 400 feet of coax cable. Will this work? Will I need a larger amplifier because of the cable length?
A tower at my house would be out of the question it would need to be about 150 feet tall to overcome the hill and trees.

This is the tvfool information for my location.
TV Fool
 

1inxs

DTVUSA Member
#2
I live at the bottom of a large hill, I can only get a weak DTV signal at my house. Yesterday I moved my TV, anttena, converter box, and amplifier (old Channel Master) to the top of the hill. I mounted the anttena on the tractor bucket and raised it about 15 feet. I can get two stations about 60+ miles away (I used to get 3 analog stations with antena on my roof).
I would like to move my antenna to the top of the hill but I would need to run about 400 feet of coax cable. Will this work? Will I need a larger amplifier because of the cable length?
A tower at my house would be out of the question it would need to be about 150 feet tall to overcome the hill and trees.

This is the tvfool information for my location.
TV Fool
Welcome to the DTVUSA Forum. Cable company's are able to send signals through miles of coaxial cable. You would need to add a preamp at the antenna sight. I'm sure one of the techies on here will have the calculation for the strength needed in over coming the resistance of a 400 foot coaxial cable. I'll do some searching and post back if someone hasn't answered that question soon.
 

Piggie

Super Moderator
#4
I live at the bottom of a large hill, I can only get a weak DTV signal at my house. Yesterday I moved my TV, antenna, converter box, and amplifier (old Channel Master) to the top of the hill. I mounted the antenna on the tractor bucket and raised it about 15 feet. I can get two stations about 60+ miles away (I used to get 3 analog stations with antenna on my roof).
I would like to move my antenna to the top of the hill but I would need to run about 400 feet of coax cable. Will this work? Will I need a larger amplifier because of the cable length?
A tower at my house would be out of the question it would need to be about 150 feet tall to overcome the hill and trees.

This is the tvfool information for my location.
TV Fool
Welcom to the Forum Hillbilly! :mad:)

I love it, now that is a man thinking! Something I might try if I had a tractor with a bucket.

Yes, you can make it work. It will evolve a little engineering and work, but it's possible.

First we need to find your TVFool plot. TV Fool This will help determine the how strong an amp you can run. But I am guessing at 60 some miles you can run a very powerful amp, which you may already own. Copy the link provided in the resulting plot back here.

We need to know which stations you are trying to pull in for 2 reasons, the right coax and all this work you might want the best antenna possible for the distance. It's best if we know the call sign of the station. The TVFool plot above will a also tell us this.

400 ft of RG6 has about 25db of loss at Ch51, which is the highest channel, thus the worst case. But only about 20db at Channel 20. VHF is only about 12 db. So all that is possible with an amp that is 29db output as it would overcome the loss, but cutting it really close on UHF channels.

RG-11 on the other hand is better, more expensive but better. It only has 29 db at 400 ft on Channel 51 , 17db at Ch 20 and about 10 db on VHF.

That is more manageable of a loss with RG11 coax.

The other thing I don't know how to figure is how long of a piece of coax can you power an amp? I know people do it up to 100 to 150 ft day in day out. Even seen it powered at 200 ft. So even if the limit (don't really know) is about 200 ft, you could run power up the hill for 200 ft and put the power supply in a very small enclosure. 200 ft of power would probably be best done with 14 gauge wire, to over come loss but a TV amp doesn't draw much power so that would work.

Hillybilly I went through a very general scenario just to give you an idea what it might take worst case to put the antenna on a hill.

We can get more specific if you like. The TVFool plot from you would be the first step.

=============

Just read the 550 ft. This just about says you need to run at least RG-11 coax for that distance. Need to look up what that would cost.

Still it matter which Channels you try to pick up.
 
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Piggie

Super Moderator
#6
Here is RG-11 that you can bury

Buy RG11 Coaxial Cable With Flooded PE Jacket 1000 Ft/Reel Black

UF rated cabel you could run up about half way to put the power supply for the amp on the side of the hill. Just have to build something to keep out water for the power supply.

I don't know how good Channel Master is at answering questions, but I just put in a question to the Winegard engineers to see how far you can power their pre-amps. Either way should give us a rough idea.
 

Hillbilly

DTVUSA Jr. Member
#8
The two stations that I am trying to receive are:

KTEJ-19 / Jonesboro - serving northeast Arkansas (PBS)

KAIT-8 / Jonesboro Arkansas (ABC)

KTEJ-19 does not show up on TVFool but I was receiving it yesterday just fine.

Running power half way up the hill would not be a problem.

Thanks!
 

Piggie

Super Moderator
#9
This is the tvfool information for my location.
TV Fool
Ok, the pig here didn't see this, sorry!

Is that TVFool plot from the top of the hill or your house? Now another thing
is TVFool does the best it can with an address and considering your hills could be a long way off from being correct.

But there is a solution!

Use this tool
Google Maps Latitude, Longitude Popup

Go to satellite mode zoomed in and find the top of your hill. Then add in TV Fool how many feet above the hill your pole will be in the height box.
 

Piggie

Super Moderator
#11
Using the goggle satilite map I plugged in the location of the top of the hill, here's a link to the TVfool information for that location with a 16 foot high antenna.

TV Fool

Thanks!
Only one deal in all of this. Finish the antenna project before you eat the pig! lol.

Wow did the top of the hill light up the sky. Plus if you can make heads or tails out of a TVFool plot, it's very obvious why the top of the hill you picked up KAIT and KTEJ. Both of those stations on paper can be received which you already proved in the real world.

Well how to procede. Do you have any idea what type of antenna you have now? Or able to take a picture of it? My question about it does it have VHF and UHF on it? If so and don't mind doing experimenting then a new antenna and amp might not be the first place to spend money.

=======

Construction concerns.

1) is I just looked at the first link I found for RG11 direct burial coax. Might find it cheaper or be able to buy less than 1000 ft of it. You "might" be able to sell the left overs on craigslist or ebay. But it's better if we find a place that you can buy only what you need.

2) There are special connectors made for RG11 and unless someone puts them on for you, you will need a tool to put on connectors.

3) The mast. On top of a hill you will need something very sturdy when the winds and snow blows, ice etc. A metal pole would need guy wires I think even at that height.
Sounds like you have some farming tools available. So I would put up a telephone pole. You can buy mobile home poles that are about the right height. You can also find poles a lot of times at the local utility company where they replace poles. Cut off what you want.
It probably violates all OSHA rules but you have a way with the bucket to get up to the top of a short telephone pole without climbing to mount or work on the antenna.
You also could buy 2 sections of Rohn25G triangular tower and bury about half the bottom part in concrete. Then it would be climbable.
The advantage to a telephone pole or triangular tower at only 15 feet or so (even 20) would be no guy wires needed.

4) Grounding. You are a target on top of a hill with lightning. Not being very high above the ground on top of a hill helps alot. You need a good ground.
Depending on if the pole is metal or wood would determine a lot of how to ground it. Any pole there should have a #10 wire down the side, the wooden probably 2 into a pair of ground rods.
Then where the power supply sits would need a ground block and ground rod.
Where the coax come in the house would need a ground block and ground rod.
That should be plenty. Lightning loves something on top of a hill then loves to run downhill looking for earth. Your wire down the hill might encourage it, hence the extra grounded.

5) we still don't know how far up the hill you will need to run power if at all (might not be needed on RG11) RG11 is 14 gauge center conductor and RG6 is only 18 gauge wire. The amp only pulls a couple of watts. The new CM uses DC current, not sure about the old ones. AC is better over a long distance from the power supply to the amp. If you have a meter you can tell, buy just unplugging the antenna from the amp and using a voltmeter to see if it's AC or DC. Also record the voltage.

I think if you find the output of the power supply is 24 to 28 Volts AC I might try and see if it will power the entire distance, before I cut it in the middle and built a little dog house for the power supply.
 
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Hillbilly

DTVUSA Jr. Member
#12
The antenna is a Channel Master VHF/UHF, I'm not sure of the model but its about 10 feet long and about 7 feet wide at its widest point. I appreciate all of the help and advise you have given me so far Piggie. I think I will go ahead and get some RG11 cable (I looked at the link you posted and I also looked at some on ebay). Thanks for tip about the ends on the RG11, I will try and find someone locally who can makup the ends or I will find someone online who can cut to length and crimp the ends when I buy the cable.
I will give it try with the current antenna and amplifier. Worst case I will keep adding stuff until it works. It is amazing the difference from the bottom of the hill to the top. The KTEG will be the harder one of the two, yesterday I was picking up KAIT with the antenna disconected and the cable dangleing 16 feet up in the air, I couldn't believe it was still coming in.
I have a really solid corner post that I can mount the pole against, I can use some guy wires on it. I will also do the grounding as you suggest.

Again thanks for all of the help, I will post my results when I get some things done.
 

Piggie

Super Moderator
#13
Sure a 4 by 4 post left over from a pole barn project would work. I lived rural most of my life and know how to make do with what was on the "farm". You repair and innovate before running to walmart.

10 ft long means it's about 10 db gain, so it sounds like it's enough antenna. I would leaving the power supply at the house first. That causes a problem in putting on ends. Putting a barrel where the power supply might be moved to then not putting it there, causes a loss. But it might be acceptable in the case you can't put then on yourself after it's all installed and you need to move the power supply.

I looked up specs and most amps are designed to be powered to a maximum of 150 ft on RG6 with is 18 gauge and 11 is 14 gauge. 14 in 120VAC household wiring will carry about 3 times the power, hence 1/3 the resistance. Now HUGE guess on my part I would think, you could power an amp to 450 ft with RG11. I am sure 150 ft is conservative so insure full power to the amp. It's probably closer to 200 ft on the outer limits (not the TV show, lol). That would make RG11 hits it's absolute limit about 600 ft.

This is why I am saying it might just work powered from the house. Typical power to a amp is less than a quarter of an amp.if 12volts and about 1/10 of an amp at 24VDC.

If you did get someone to put ends about half way you could see if the signal is better with the power supply half way up the hill. Even with 12 or 14 gauge extension cords you can power an amp power supply to about 300 ft as it pulls so little current. Why I said you could power it remotely with 14 gauge UF cable. It's safer in PVC if you ever dig in the area. But they make UF cable for direct burial.

But a friend of mine just priced NM cable in PVC and it was cheaper to run to a shed he has. UF costs a lot more than NM. He said he could buy the PVC for the less than the difference in price and probably protect his cable better.

It's more expensive but I would not run the coax and power in the same PVC in case you are thinking that. Two reasons. More chance of noise unless you buy really expensive RG11 that is flooded for burial and it's quad shield. I don't think you need quad shield as most of the run is underground where there isn't any noise (unless the power wire is in the same piece of PVC). Also if hit by lightning, there is a good chance the wires side by side in PVC would arc over considering they would be that way for couple hundred feet at least.
 

Piggie

Super Moderator
#14
WINEGARD COMPANY • View topic - How far can you power a Pre-Amp

Their amps are good for 150 to 300 ft on RG6, which is in line with what Channel Master claims. So if a Winegard will work for 1000 ft on RG11, so should a CM. RG11 is big coax so it has less loss even for just power.

with 550 ft of RG11, you will have about 23 to 24 db of loss. Lets hope your amp has a lot of UHF gain. Something in the order of 29 db for channel 20. KAIT on channel 8 won't be a big problem at all. Only about 14 db of loss at Ch 8

Still that is doable with a big CM or Winegard amp if yours is not powerful enough. Yours is worth trying
 

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