OTA: The Big Trees Factor

21039 Views 55 Replies 20 Participants Last post by stampeder, May 23, 2011

stampeder

Discussion Starter · Jun 25, 2005 (Edited)

tigerbangs said:
Stampeder: get that 4228 and the 1111 up on the roof and quit your stalling!

Oh the irony! Here I am cheering on OTA converts, yet I can't enjoy it myself the way I'd like to! I am chomping at the bit to get those up and running but actually I've now done 2 test placements on the roof and the results were really awful due to the tall trees. I can't seem to find a sweet spot anywhere in the yard after dragging around my CM4228 on its mast, with my LG tuner with a 13" TV in tow. Also 4DTV_HD offered to come by with his spectrum analyzer to see if we can find one but I doubt that we would so I don't want to waste his time. I had to put my ugly little satellite dishes up on a 10' pole in my vegetable garden just to see the BEV sats.

My only choices are

1) put up a 60' tower
2) chainsaw massacre (illegal - the trees are protected, and we love them too)
3) move
4) climb that big tall fir tree and put all the gear up there (not!)

We'll see, but I tell ya its frustating, like having a Jacuzzi with no water connection.

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robcreaser

· #2 · Jun 27, 2005

stampeder said:
We'll see, but I tell ya its frustating, like having a Jacuzzi with no water connection.

One more choice would be to install a low noise amp. You didn't say in your test thread if you received low signal strength or no signal. The centre point of my 4228 is only five feet above the ground and looks directly horizontal into a row of tall hardwood trees about 20 feet away. With the amp I have no problem digital signal locking on stations about 80 miles out. Without the amp I get nothing. Leaves/trees cause scatter (and signal reduction) as opposed to multpath. If you can get raise the remaining signal quietly above the background noise floor digital reception should be possible. Analogue stationa will still look like crap.

stampeder

Discussion Starter · #3 · Jun 28, 2005

robcreaser said:
One more choice would be to install a low noise amp. You didn't say in your test thread if you received low signal strength or no signal.

Thanks - my CM4228 runs through a Winegard AP8275 preamp so it has about the highest gain setup a person could get. Were you referring to that, or to a further amp in the chain? With the present setup most expected signals are too low for a lock.

Tom.F.1

· #4 · Jun 28, 2005

4228 antenna mount

I just read my family Stampeders post about nowhere to mount the antenna.
They voted for chopping down trees, but i like the 60ft tower idea.
And they were laughing at me for building a mini cn tower on my roof. OK, i might have overdid it a bit on the mast. It's only 12 ft and sits on the peak of the roof. I guess i could have put it at the back of the house rather than the front, but it was the shortest cable run, so it made perfect sense to me. The neighbours were all gathered accross the street, wondering what i was up to and how was i going to get that big thing up all by myself. It's amazing what you can rig up with a couple ropes.

stampeder

Discussion Starter · #5 · Jun 28, 2005

Tom.F.1 said:
I just read my family Stampeders post about nowhere to mount the antenna. They voted for chopping down trees, but i like the 60ft tower idea.

Ooooooo.... them's fighting words around the Vancouver area!

The relentless sprawl of suburban development is costing us more and more beautiful old firs and red cedars around here, and people have started to get really irate about tree chopping. We love our trees, so I just would not have the heart to cut them even if protecting them wasn't in a property covenant. I think we might even be leaning towards moving, but not because of my dear antennas!

Nevertheless I've marked out other areas on maps out here that would get good reception.

Here are some photos of my tree predicament:

http://www.digitalhomecanada.com/forum/showpost.php?p=207003&postcount=22

026163

· #6 · Aug 2, 2006

Mounting Antenna In a Tree?

i have a brand new CM4228 antenna, and I plan to use it specifically to recieve Toronto channels. (my yagi gets all Buffalos at 100%)

how would it work out if I wedged my CM4228 among the branches of a very tall tree in my yard.

this would get it up higher than if I mounted on top of my roof.

anyone tried this? is it a good....or bad idea?

thanks

stampeder

Discussion Starter · #7 · Aug 2, 2006

Trees as Antenna Masts

026163 said:
how would it work out if I wedged my CM4228 among the branches of a very tall tree in my yard

I investigated that sort of thing once before because I have a massive ~150 foot Douglas Fir on my property that stands above everything else for miles. My neighbourhood is also on a hill. Wow, the reception up there would be spectacular! Here's the problem:

No matter what the size of the tree, the ATSC digital TV standard is meant only for stationary reception and was never meant for moving antennas. A tree is a dynamic structure, even if it is completely dead, so by mounting even the best of antennas in one you are guaranteeing that with even a small amount of branch or trunk sway you will get minor pixelation and/or audio dropouts at the least, and complete dropouts in high winds at the worst.

Sorry to be the bearer of bad news.

Save

300ohm

· #8 · Mar 22, 2009

I believe because of the trees.

Trees like fir and pine are like a steel curtain at uhf frequencies.

Grand Audio

· #9 · Mar 22, 2009

I'm surrounded by 80' pine trees. With a lot of hickory and oak scattered amongst them. When the leaves and pine needles come back, I'll really be in trouble.

mclapp

· #10 · Mar 23, 2009

Evergreen trees will really knock down a TV signal, I've seen many times when an antenna near the ground pointeing below the tree branches will work much better than one higher pointing into the bulk of the trees.

If you are receiving stations in a different direction of where you should it could be a reflection. I have a station I can receive some times that's located NW of me but only get it when I'm pointing my antenna SSW and getting a bounce off of a near by hill.

I can't explain your odd reception conditions, but I will explain how things should effect the antenna and maybe that will help.

If you are using swept forward elements the signal should be stronger in the swept forward direction (about 1-2db). If the elements are flat you should get a reception pattern nearly the same either direction, broadside to the elements.
Make sure that the reflector is oriented so that the 2" spacing is running horizontally and the 4" spacing is running vertically.

This style antenna has a narrow vertical beam width, depending on ground conditions, they will work quite well at near ground level compared to some.

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stampeder

Discussion Starter · #11 · Mar 23, 2009

Grand Audio said:
I'm surrounded by 80' pine trees. With a lot of hickory and oak scattered amongst them. When the leaves and pine needles come back, I'll really be in trouble.

My world and welcome to it...

Douglas fir, red cedar for year round attenuation, maple and birch for summer/autumn signal killing. Its an OTA nightmare here so I've had to take extreme measures short of getting out my old chainsaw and then getting fined/sued!

mclapp said:
Evergreen trees will really knock down a TV signal, I've seen many times when an antenna near the ground pointeing below the tree branches will work much better than one higher pointing into the bulk of the trees.

I can confirm that 100% - CM4228 at ground level below trees:

http://www.digitalhome.ca/forum/showpost.php?p=207003&postcount=18

Massive trees on my property:

http://www.digitalhome.ca/forum/showpost.php?p=221345&postcount=44

300ohm

· #12 · Mar 23, 2009

My world and welcome to it... Douglas fir, red cedar for year round attenuation, maple and birch for summer/autumn signal killing. Its an OTA nightmare here.

Red cedar as in sequoia ? Use the trees to your advantage by making them towers, heh.

stampeder

Discussion Starter · #13 · Mar 23, 2009

Thought about it.

4 years ago i thought about putting them up on top of the Douglas Fir but the posts I gave mention why I didn't. Also a tree is a dynamic being, so ATSC digital locking would be constantly ruined by the motion in even a slight wind.

The red cedars are similar to sequoias in that the tops are very slender and not very solid. A guy in a nearby neighbourhood put his ham radio antenna up on one, but after a few wind storms it lay to rest so deeply entwined in the upper small branches that he had to leave it there. He has a metal tower and new antenna now.

300ohm

· #14 · Mar 23, 2009

that the tops are very slender and not very solid

Yeah, but you have the option of topping the tree (it will still grow) and mounting down further where its thicker and less prone to sway.

I have about a 100 ft sequoia in my yard about 40 feet away from the coax in to the house. Its a good 25 ft higher than any other tree in the immediate area, heh. Ive been seriously considering mounting an antenna up there. I picked up 200 ft of RG6 Quad cheap. Just need a preamp and some decent weather, heh.

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stampeder

Discussion Starter · #15 · Mar 23, 2009

True, but in moderate winds the flex of the tree goes down about 2 thirds its height, so the ATSC locking problem still exists. On analogue you get the visual equivalent of "wow and flutter" when the trees are moving.

300ohm

· #16 · Mar 23, 2009

Hmm. Ill have to ponder on that, heh.

stampeder

Discussion Starter · #17 · Mar 23, 2009

Two or three times a year we get gale-force winds off the Pacific and the deadfall from out of those trees is awful. Occasionally we get a real whopper like the one that knocked down over a thousand such big trees all around Vancouver a couple of years ago.

You get some really nasty ones off the Atlantic, don't you?

Grand Audio

· #18 · Mar 23, 2009

Here is a picture that will give some idea about the trees I am dealing with. This photo is taken looking just a little east of north. Photo was taken in January 2003.

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300ohm

· #19 · Mar 24, 2009

You get some really nasty ones off the Atlantic, don't you?

Yep, pretty much 70 mph winds at least twice a year. We have been very, very lucky. No huricanes have hit since 1954 ? (so I been told, dont remember, heh). But looking over the history, we are way way overdue. Of course, the cause will be man made global warning, even though a surprise huricane in March of 1898 completely wiped out over 100 tall ships at Lewes on the Delaware coast tip, killing many hundreds. The wreckage was still there when I was a kid in the 50's. Since then its finally been removed, heh.

Hmm. Ill have to ponder on that, heh.

Hmm, a gimbal mount mast may be the solution. I built many a gimbal mount drink holders for my boats. Cant spill that precious beer, no matter how high the wave, heh.

Also, you have to admit, the sequoia is a very good climbing tree, heh.

300ohm

· #20 · Mar 24, 2009

Here is a picture that will give some idea about the trees I am dealing with.

Look on the bright side. Pines are better than firs for UHF reception, even though both are pretty bad, heh.

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