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Cheap DIY free standing antenna mast?

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Old 08-19-2010, 01:46 AM   #1
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Default Cheap DIY free standing antenna mast?

Hello, kinda lost for what direction to take right now to improve reception on a tight budget


tvfool . com/?option=com_wrapper&Itemid=29&q=id%3d9fbe2f67783c5 6 (remove spaces around "dot")



any educated guesses weather 20' mast will get me ABC?

used to have a CM4228 just bolted to the side of the small cabin at 6' off the ground facing east toward Gainsville 30 miles away, one nice thing was it was right next to the TV total cable length was less than 4', pulled in PBS (wuft) fairly reliably, CBS (WGFL) about %50 and on a rare day ABC (WCJB)

biggest reception killer for me is trees, I live in an oak forest and all the way between me and the towers is solid dense oak forest over 75' tall. I know I don't have the budget to get above the trees or even close. living in the lightning capital of the world not sure I want to get too high anyway.

put up a new larger home on the land new place has lot more cable, its about 20' of RG6 to the ground point and right now I have about 40' more to the antenna, when I get it settled in its final resting spot I'll cut it to length, unfortunately closer to the home is denser trees,

I moved the antenna over there on pipe I had around, about 14" long, with a bout 3' in the ground and bottom of the antenna is 9' above the ground higher than previous place but right now all I can get is the 3 channels of PBS, just not gonna cut it,


at one point I was moving things around and just rested the mast with antenna against a tree and CBS came in, it seams the 3' difference between buried and sitting on top of the ground made a notable difference, I would really like to get CBS and ABC, would like fox also but don't think it is possible without extreme measures. I think I need more height, mast cannot go on roof or be attached to home as it has no solid attach points.


so what are good cheap DIY free-standing mast options? 20' height maybe? would like something that could be turned a little bit to adjust the antenna, at first I thought a 5' stick of 1 1/4" sch 40 galvinized pipe in the ground in concrete and then another 21' in the air with a coupling in between but its so heavy and flexible not sure it will work, I guess I could 3 point guy wire it but then I cannot rotate it from the ground


are there better options for DY antenna mast material? lighter and more rigid?




Another question, antenna location, I can have a small clearing or shorter cable, but not both, how much of a factor is cable length? with my current short portable mast I do not seam to get much better in the clearing but it is hard yo say asmoving the antennea a few inches changes the reception, another factor is I am going to set a ground rod at my antenna mast and if I am within 20' of my ground rod/service entrance I can connect the two ground rods with a #4 copper, any further (the small clearing) and its off a spool of #10 I have.

Last edited by rbinck; 08-24-2010 at 03:08 PM. Reason: Address removed per member's request
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Old 08-19-2010, 07:21 AM   #2
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Quote:
Originally Posted by RavenTai View Post
are there better options for DY antenna mast material? lighter and more rigid?
http://www.channelmasterstore.com/An...Masts_s/42.htm

Consider a telescoping 30' mast. It has guy rings that allow rotation. Mount it to the side of your house with an eave or wall mount bracket. Stand on the roof to extend the 10' sections.

Lower it when a hurricane is predicted.
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Old 08-19-2010, 07:30 AM   #3
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Hello Raventai and welcome to the forums.

The situation is - that none of us has a magic crystal ball that can see your situation and can predict with a 100% accuracy what is going to happen in the future.

So your question should actually be - what do I need to do to get ABC

Here is the license information for WCJB
Channel 16 - Gainesville Florida
834' 343.6 kW DA - 44 Mile Contour
9 kW TPO + 17.2 dB gain = 343.6 kW ERP
Transmit antenna height above ground level - 850'
Location of transmitter - N 29 32' 11" (29.536), W 82 24' 0" (-82.4)

Now here is the situation, in order to compare apples to apples - you first have to understand that the analog was by most comparisons - a much stronger signal then the digital.
The digital, in order to receive it correctly - is going to require you to have a UHF antenna, lot's of height, a antenna rotor, a pre amp to compensate for line loss and some good wire. You already understand about lightning protection - so we don't need to go into that.

Now here is the other half of the story - like Paul Harvey would say.

If all that a person looked at was the distance, then they would assume that it was no problem to pick up a television station 30 miles away. But looking at the license - the output power is very weak - hence a local signal.

My understanding is that most of Florida is at or even slightly below sea level, which makes a excellent opportunity for reception in the neighborhood of 120 miles in any one direction on a good day.

Since you are already growling about the trees in your neighborhood and since you have no way of cutting those trees down, the next step is to look into some type of assistance to get your antenna as high up as possible and some type of antenna that has a better gain then what you are already using.

The key was that we needed to have your equipment list - because again - our crystal ball is broken and we can't see what you are trying to use.

Your strongest station is WGFL out of High Springs and it's output power is not much better then the WCJB = which I believe the FCC did to protect the larger markets many miles away. So it is not a bad thing, just something that needs to be worked around.

Since all your major market stations are on UHF, if you were willing to throw away WLUF - The University of Florida, and WNBW - NBC? and the LP translator - W40CQ - Religious Channel...

You could get by with nothing more then a good UHF antenna such as the Antenna's Direct XG 91 and a Channel Master CM 7777 pre amp and a antenna rotor and a telescoping mast or a antenna tower.

http://www.tessco.com/products/displ...upId=70&page=2

http://www.tvantenna.com/support/tutorials/towers.html

A 65 foot tower should get you the reception that you are looking for. A 50' telescoping mast should really help you out - if you were not looking to invest the money into a tower.

The price vs performance, the telescoping mast - you are going to give up land - since you will have to use guy wires. The tower you will have to part with your money.

Couple that to some good communications grade RG 6 wire and you should be in business.

Nothing good in life is cheap - as you have already found out.
If you want to play - (or in your case watch) first you have to pay!
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Last edited by Columbo; 08-19-2010 at 07:34 AM.
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Old 08-20-2010, 10:34 AM   #4
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Bury a pipe in cement, so that a few feet are above ground. Then you could slip a larger diameter pipe over that, lock it down with a couple nuts welded to the outer pole (a bolt would thread onto this nut and push onto the inner pole), and then stabilize with some guy wires. Sounds like that's what you were thinking.

For the outer pole, you could get away with electrical conduit. I did this with good results. A few lengths can be welded together, sanded, primed, and painted. Then once your antenna is mounted and the wires are routed down via standoffs, you can slip the long pole assembly into the cemented pole. It might take 2 people to lift it and a couple others to stabilize it. You should be able to put 3 or 4 10' lengths together like this.

For the guy wires, you can probably weld some sort of flange and then put a free moving ring/collar on top of that, connecting the guy wires to the ring. This would provide rotation of the mast and flange, while the ring stayed stationary.

Tuning would be as simple as rotating the pole and locking it down.
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Old 08-21-2010, 09:03 AM   #5
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I'm sorry, but I have to disagree with you on this one.

From an engineering standpoint, electrical conduit is a poor mast.
It is engineered to hold electrical wire and be bent easily.

When you build a mast - you are looking for at least two things.
DOM - Drawn Over Mandrel - which pulls the tubing over a mandrel and creates a consistent OD/ ID and adds rigidity. And galvanization or Chrome Moly - which add's rust proofing.

The electrical conduit is not galvanized to the point of where you can put it in concrete and leave it outside for a extended period of time.
The concrete by nature is corrosive and it will rust off at the point of where it comes out of the concrete every time. The conduit - is only a single stage galvanize - because it is designed for indoor use only.

Today's electricians uses plastic conduit for outside work, along with aluminum.

The wall thickness required for a good, strong, single pole mast would probably be somewhere in the neighborhood of .120 x 1.500"

http://www.goodmansteelsupply.com/Page%203.htm
DOM 1.5 X .120(1.260 ID)@1.769#

The problem that most people gets into when they put up a antenna is that when they find that a single pipe is not strong enough, they resort to some type of thrust bearing. When they find that the bearing requires a certain OD to work for the thrust bearing and their pipe is not the right OD - they try to shim it. Usually what happens is that the bearing works against the internal bearings inside of the rotor and the antenna wobbles as it turns.
In the winter - the bearing freezes and the antenna won't turn in the northern climates and in time the rotor wears itself out and dies.

This is where I buy my fabrication materials - http://www.samuel.com/en/Pages/default.aspx
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Old 08-23-2010, 07:26 PM   #6
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Originally Posted by Columbo View Post
From an engineering standpoint, electrical conduit is a poor mast.
It is engineered to hold electrical wire and be bent easily.
It doesn't bend all that easy. That's why we use pipe-benders for EMT. I've made several masts with 1 1/4 or 1 1/2 EMT and it worked out fine. Super strong ?? No. But just as durable as pre-made steel mast material if put up properly. Just because something is primarily made for one purpose, doesn't mean it cannot be used for something else. Look up what Viagara was oriiginally used for, and it's quite different then what it's used for now.

I've got two 21 foot antenna systems, all in extremely high wind areas on top of the mountain behind my home. One has four antennas on it (lots of metal sails). Both are as thus. 14 foot pressure-treated 6" x 6" with four feet buried and 10 feet sticking above ground. I've got a 10 foot section of 1 1/4" EMT slid inside a 10 foot section of 1 1/2 EMT and they're bolted together with a 2 foot overlap. I.E., 18 feet of mast. That is strapped on to the 6" X 6" post with the bottom end three feet off the ground. That leaves 11 feet of unsupported mast above the post. Four feet above the post, I've got three guy wires, all running to ground-rods with turnbuckles. So, in reality there is 7 feet of totally unsupported mast in very high wind. It's been through the torture test. Mast held up find, but a few antennas did not.

I can turn the mast pretty easy, just by loosening a few nuts and lag screws.

I also have a 8 foot unsupported antenna mast with factory made 1 1/4 mast material, and it bent over backwards last winter - with a Winegard HD8200 on it.

I'm not saying EMT is the best material out there, but it does OK. Note I'm talking about standard EMT. There is also heavy-duty EMT which is even stronger. Nice thing is Home Depot is nearby and it only costs about $7 per 10 foot section. One concern is when you bolt metal against wood that's been ACQ treated instead of CCA. Hot-dipped galvanized does OK, but electroplate steel, or worse . . aluminum, needs some sort of barrier between it and the wood. A rubber shim works fine.

I'll also add that a post as big as a 6" X 6" may seem like overkill. But, the problem is . . . nobody that I know of makes a treated 4" X 4" that's rated for burial, which is a joke. Same goes with most 6" X 6" posts if 10 foot or shorter. So, if you want to bury a post that won't rot, read the small print in the treatment tag, which is likely to be ACQ. If it says "ground contact", that means it is NOT rated for burial and has a cheap treatment. Things have changed a lot when most treated wood got switched from CCA to ACQ. ACQ is more pricey, so the treatment has been cut way back on standard "treated" lumber.
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Old 08-24-2010, 01:05 AM   #7
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Thank you all for the suggestions, sounds like I need to put something up see what I get and go from there, I probably should have said ghetto not just cheap in the title. there will be no commercial masts, and no rotor besides my hand.

went shopping today picked up the following:
three: 1 3/8" x 10.5' 18 gauge chain link fence top, $26.91
one: 3/4" x 6' galvanized pipe, $14.21
three: 30" ground anchors, $31.32
two: 80 pond bags of 5,000 PSI concrete, $9.96
one: copper clad 8' ground rod, $8.97
one: 1" galvanized flange. $7.95
ten: 1/4"x2" galvinized bolts, gal nuts, 25 gal lock washers, $8.70
six: wire rope thimbles $2.88

Total $110.90, if it gets clobbered by a tree I wont cry

materials I already have,
Channel master 4228 8 bay bowtie UHF antenna,
coax ground blocks, ground rod clamps,
20' #4 solid copper wire. spool #10 solid copper,
spool of RG6, spool of galvanized steel electric fence wire,
Ideal conductive grease.


so here is the current plan:


Dig a hole about 4' deep, about 6" in diameter, pound in the ground rod in the same hole leaving it a few inches above grade, temp secure the 3/4" galvinized pipe and pour the concrete leaving a bit over 2' of pipe and a few inches of ground rod above the concrete.

then set the three ground anchors 120 degree apart at the same distance from the mast as the height of the mast. put thimbles on.

slide the sections fence top together drill two 1/4" holes 90 degrees apart at each joint, and secure with bolts, add another bolt for the flange to rest on about a foot below antenna,

open up center hole in flange to get a close but sliding fit on mast, drill 3 holes in the flange at 120 degrees install thimbles for clean radius for guy wires, and slide on mast until it stops on the bolt.

attach antenna above flange, attach #10 copper ground to top of mast, run ground lead and RG6 down mast,

for guy wire going to use the electric fence wire quadrupled, should give me well over 100# load per side.

lift the mast and slide over galvanized pipe, secure guy wires, its just me, I am reasonably strong and all the components together don't weigh that much, maybe 50 pounds? but something tells me at 30' of leverage its going to be difficult. i am hoping once I can get it near vertical then it is just a dead lift straight up to get it over the gal pipe,

my only helper is an elderly woman on chemo, best I can hope from her is she can dial 911 if I really mess up. I may have to drop back to 20' if the 30' is too unwieldy

grounding, going to ground the #10 from the top of the mast to the mast ground rod, going to run a #4 from the home ground rod to the mast ground rod, will have coax ground blocks at both rods.

I am putting the upper 4' or so of the ground rod in the concrete for a few reasons, one it gets the rod very close to the mast, it also should provide a bit of a Ufer ground, the 6" diameter of concrete having a lot more surface area than the rod 5/8" rod,

but I am not certain of the long term performance of copper clad steel in concrete, does concrete and copper get along?



I am hoping to get away without an amp. only load is a about 60' total run of RG6 through the two ground blocks to a coax surge protector and then through to a single HDTV, no splitters.




any recommended changes?
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