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Discussion Starter · #1 ·
I'm in a relatively deep 'fringe' area by the station locating sites in TV Fool and AntennaWeb and I'm losing good signal with a roof 4-bay model that claims reception at as much as 60 miles. It works fairly well in the summer but becomes nearly unwatchable if it snows, which it does.


Most of the network station transmitters are within four degrees of each other - the Portland, OR towers and are 24.5 miles from here as the crow flies. However, there are tall trees and terrain between me and them.


So I'm looking to raise a better antenna on my roof and know that a big directional yagi design will be the best possible solution.


BUT, the CM3671, the big guy from Channel Master is approx. 14' x 10' huge.

That would be cumbersome to erect in my old condition and be subject to occasional 30+ mph wind loads with snow, ice, and squirrels adding to the fun. (OK, I could shoot the squirrels).


I see relatively small and highly technical-looking antennae at various sites with claims that seem impossible considering their sizes and the old rules of "big is best" and "higher the better".


So does anyone know that these sorts of claims are bunk, and the kind of newfangled and spacey-looking antenna designs don't usually work as claimed?


ARE there any of these developments in antenna design that reduce the sizes of the tried and true big boys and actually work anywhere near as well as a nice big well designed Yagi beam?


And if there are any that anyone KNOWS perform anywhere near as well as that big Channel Master, which are they? Because I'll buy one and cost doesn't matter.
 

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"technology" can't do anything about the laws of physics.
 

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+1

Another thought, have you considered a 8 bay bow tie? Double the gain of your 4 bay(physics again
) and not nearly so long as a yagi.

The 8 bay bowtie is my favorite antenna for weak signal areas. That yagi would probably be best where you were trying to get rid of multipath since I believe it has a narrower beam.
 

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Quote:
Originally Posted by Scooper /forum/post/19537154


"technology" can't do anything about the laws of physics.

Nor can deceptive marketing nor fancy design and packaging..
 

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An 8 bay bowtie isn't going to cut it for poor reception in a market with 3 major networks on high VHF. I believe the CM3671 is designed for low VHF as well as high VHF and UHF, and those big elements for low VHF add a lot of wind and ice load for no benefit. I'd look at a Winegard HD7698P. It's not small at 168.25x53.5, but it still comes in well under the CM's 173x110, and probably outperforms the CM.
 

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What coyote said.


The 3671 is a poor choice because the long lowband VHF elements:

1. Make it more awkward to install than the 7698P that coyote suggested.

2. Increase wind loading and susceptibility to ice/snow damage.

3. Are not needed for the channels in the area,

4. Pick up FM radio, which may cause interference with highband VHF.
 

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Is it just the VHF-hi stations you are having problems with or is it all the stations? The reason why I ask is the 4 bay bowtie antenna you have is a poor performer on VHF-hi as already stated, there are some simple mods that can make it 4-6 db better in the forward direction on VHF-hi but that may or may not still be enough.

I did a test on a CM4221 4 bay (the chart is at the bottom of that page) by simply adding some threaded rod (any metal would work) to the back of the reflector screen I got a pretty good gain boost. It's still not great nor anywhere near a 7698P but may be enough and would only cost you some metal rods 30+" long and some time.


I see you mention trees in your path to the transmitters location of the antenna is very critical when looking through the trees. Sometimes higher isn't better it may put you right into the thickest part of the trees. Try to find a path of less resistance through the trees even if it's only 5ft above ground, I've seen instances where that was the best (below the trees)


These are just some suggestion to maybe save you from going out and spending $$$ I'm sure the 7698P will get the job done.

Just like everything in life it either takes time or money sometimes both.
 

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Discussion Starter · #9 ·

Quote:
Originally Posted by Scooper /forum/post/19537154


"technology" can't do anything about the laws of physics.

Yeah, that's what I thought.

Quote:
Originally Posted by coyoteaz /forum/post/0


An 8 bay bowtie isn't going to cut it for poor reception in a market with 3 major networks on high VHF. I believe the CM3671 is designed for low VHF as well as high VHF and UHF, and those big elements for low VHF add a lot of wind and ice load for no benefit. I'd look at a Winegard HD7698P. It's not small at 168.25x53.5, but it still comes in well under the CM's 173x110, and probably outperforms the CM.

and arxaw,


Good info - Thanks. I'll look at HD7698P.


I hope it was clear enough that I'm sceptical of the assorted claims. My father was a ham and I grew up under a beam antenna on a tower that would cast a shadow over my present house. Although I now regret not wanting to get more involved with him and that, it did give me a grounding in some of the principles and of what works and what doesn't work.

Even so there has been growth in so may areas that I had to ask about TV antennas.


The best part is Coyoteaz's info on the high/low vhf because I didn't know it and don't see that either of the antenna finder sites differentiate. I'm just seening "vhf" and "uhf" on their charted info.
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by mclapp /forum/post/19539004


Is it just the VHF-hi stations you are having problems with or is it all the stations? The reason why I ask is the 4 bay bowtie antenna you have is a poor performer on VHF-hi as already stated, there are some simple mods that can make it 4-6 db better in the forward direction on VHF-hi but that may or may not still be enough.

I did a test on a CM4221 4 bay (the chart is at the bottom of that page) by simply adding some threaded rod (any metal would work) to the back of the reflector screen I got a pretty good gain boost. It's still not great nor anywhere near a 7698P but may be enough and would only cost you some metal rods 30+" long and some time.


I see you mention trees in your path to the transmitters location of the antenna is very critical when looking through the trees. Sometimes higher isn't better it may put you right into the thickest part of the trees. Try to find a path of less resistance through the trees even if it's only 5ft above ground, I've seen instances where that was the best (below the trees)


These are just some suggestion to maybe save you from going out and spending $$$ I'm sure the 7698P will get the job done.

Just like everything in life it either takes time or money sometimes both.

Looks like we're crossposting, mclapp.


Yes, the trees are a problem. When I bought this place the owner had an antenna mounted to the chimney at the southwest end of the house. He lived with two channels. To get to Portland needed to fire the antenna directly into a stand of 100'+ Douglas Fir that are just over 30' from his antenna. I put the four bay (it's a Winaguard but I don't recall the model) on a tripod at the other end of the house. Those trees load up with snow.


I like your idea of shooting under the tree branching but I'd need to have the trees scaled for it to work.


I was thinking to attach a pole to the northeast end of the house to gain some 40' distance from the thickest part of the trees and a careful aiming should get me between them. I'm at approx. 900' elevation and the house is sited on an excavated slope facing due south so I think that if I can walk an antenna location to a spot where I can aim at 202-204 degrees through the tree trunks it'll be as good as possible. This is what the DishNetwork guy had to do to get a south shot at their satellites, and I had to coax him to keep trying when his first impression was that it wasn't gonna' work.


The bottom line is that locals aren't necessary, but I'm fixating. I turned down Dish's local option because their $7.00 monthly fee didn't include Portland OPB, and I know that the OPB channel booms in here under most any condition (so far). I can get that one with rabbit ears when the sky is clear. Besides, $84. a year, year after year will buy me one heck of an antenna!
 

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Quote:
Originally Posted by krs /forum/post/19537136


I see relatively small and highly technical-looking antennae at various sites with claims that seem impossible considering their sizes and the old rules of "big is best" and "higher the better".


So does anyone know that these sorts of claims are bunk, and the kind of newfangled and spacey-looking antenna designs don't usually work as claimed?


ARE there any of these developments in antenna design that reduce the sizes of the tried and true big boys and actually work anywhere near as well as a nice big well designed Yagi beam?.

It seems that someone in China has recently discovered that adding a rotator to an antenna will always double the antenna's range. While they may not be lying, they surely aren't telling the truth.


Have you thought about a VHF (ch 7 -13) antenna and a separate UHF antenna. Usually this can be done for the same or slightly less money than a big, single antenna.
 

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Discussion Starter · #12 ·
mclapp, I'm looking at your site...and I've got a half roll of reflector material


I like that you've done the science.


I need to take a closer look at the actual situation here now that it's snowed a little, maybe 3" a day or so ago. Right now everything's pretty crunchy outside with 20.8 degrees freezing the residual snow.


Also I need to get up on the bank behind my house and see if I can take some shots in the right directions better from up there. The trees are all over 100' tall so even with my house elevated maybe to close to the height of the station towers I'll still need to get a look between them. The locator charts show all of the prime channels as line-of-sight and there are no structures nearby so it's all about trees and weather.


One thing I do know is that I only want to do whatever I do once.
 

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krs:


Just to add to the already excellent comments here, with many stations having abandoned VHF-low (channels 2-6) for digital broadcasting due to interference and other reception problems, many parts of the country no longer need VHF-low-capable antennas having the very long elements. With the exception of a low-powered digital VHF-low station on channel 4 and two low-powered analog VHF-low stations on channels 5 and 6 (that many people might not be interested in), Portland appears to be such a city (based on TVFool.com results). As a result of this, antenna manufacturers have introduced combination VHF-high/UHF antennas (like the Winegard 769x series) and dedicated VHF-high-only antennas (like the Winegard YA-1713), with maximum element width (for channel 7) only being about 35" at the rear of these antennas.


So, while the laws of physics haven't changed, the elimination of the need for long VHF-low elements provides opportunities for improved VHF-high and UHF reception by using somewhat larger antennas designed for those bands only, without the antennas looking so huge up on the roof. Also, many people on these and other message boards often find superior antenna performance by using separate VHF-high and UHF antennas, mounted 3 feet apart on the same mast (usually with the UHF antenna on top), joined at the antenna by a UVSJ, with a single coax fed from there to the tv. Portland does have three VHF-high stations (on channels 8, 10 and 12), so you'd definitely need that VHF-high capability.


Many people also feel that the length of an antenna boom is the primary factor for deciding whether an antenna looks huge up on the roof. Longer range combination VHF-high/UHF antennas (such as the Winegard 769x's) do tend to have a long boom length. But when you switch to separate antennas, that long length is reduced (even though you now have two antennas), which many feel makes for a less obtrusive appearance.


In your situation, it would also be easier to mount separate antennas individually, because they would weigh less and be smaller to handle generally. UHF possibilities recommended by many on these boards include relatively small 8-bay models (such as the Channel Master 4228HD, Winegard HD8800 or Antennas Direct DB-8) which would provide better gain than your present 4-bay. The Antennas Direct 91XG is also an excellent UHF antenna, although it is a larger design. Any of these UHF-dedicated antennas would provide better UHF gain than all but the very largest combination VHF-high/UHF antennas. VHF-high antenna possibilities include the Winegard YA-1713 or Antennacraft Y10-7-13, both of which would again provide better VHF-high gain than all but the very largest combination VHF-high/UHF antennas.


Gain figures of many of these antennas are provided so you can compare, and the Winegard models even separate gain figures by channel ranges (see "Specifications" tab for each), and dimensions are also provided for each antenna:

http://www.solidsignal.com/pview.asp?mc=03&p=4228-HD
http://www.solidsignal.com/pview.asp?mc=03&p=HD-8800
http://www.solidsignal.com/pview.asp?mc=03&p=DB8
http://www.solidsignal.com/pview.asp?mc=03&p=91XG
http://www.solidsignal.com/pview.asp?mc=03&p=YA1713
http://www.solidsignal.com/pview.asp?mc=03&p=Y10-7-13
http://www.solidsignal.com/pview.asp?mc=03&p=UVSJ


If it turned out that you were interested in receiving the low-powered VHF-low channels, a recommended solution is a Winegard HD5030 (a VHF-low/VHF-high only antenna) along with a separate UHF antenna. Of course, the HD5030 is much longer and wider because of its VHF-low capability, but still would perhaps not look as huge as a Channel Master 3671:

http://www.solidsignal.com/pview.asp?mc=03&p=HD-5030


Hope this is helpful - good luck with your installation...
 

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Quote:
Originally Posted by krs
...The best part is Coyoteaz's info on the high/low vhf because I didn't know it and don't see that either of the antenna finder sites differentiate. I'm just seening "vhf" and "uhf" on their charted info.
US digital TV bands:

LO-VHF = channels 2 thru 6

HI-VHF = channels 7 thru 13

UHF = channels 14-51


Few US stations are in the LO-VHF band because it is prone to interference problems. VHF is also harder to receive indoors.


Stations often still use their old analog numbers for ID-ing. On the station finder sites like TVFool, etc., look at the "Real" "Transmit" or "RF" channel column for the channels that are actually being used.
 

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krs,

Getting further from the trees will sometimes help, I have to deal with a similar although less severe condition at my home. Just like signals coming over a hill they will bend slightly downward as they come over the trees and getting the antenna further away will help catch them. My trees aren't that high, I was able to get my antenna on a pole to near tree top level. The combination of moving the antenna further away from the trees and near tree top level made a hige difference.


In your case I'm sure 70 - 100' up is pretty much out.



If you have some reflector material like wire fence you don't have to completely cover the exsisting reflector to inhance VHF-hi if you don't want to. Just use strips of it spaced evenly along the current reflector make sure the majority of the wires are running horizontal.
 

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Quote:
Originally Posted by walford /forum/post/19540850


AFAIK Portland has no lower VHF channels anbut does have several UHF channels in additon to UHF channels.

Zipcode and/or TVFool can easily verify about frequency allocations.

I am sure that there are "several UHF channels in additon to UHF channels."
 

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Discussion Starter · #18 ·
All great info....Thanks much to everyone!


mclapp, ya, I'm afraid going up enough to be over these treetops is out of the question although I used to know a guy when I lived in the hills northeast of Santa Cruz, CA who installed antennas in the treetops of 100 - 150' Redwoods. He was an ex-treeworker and would go up, top the tree, and install a pipe with spikes and plumber's tape for $25. I had him put a CB antenna up in one of mine and it's probably still up there today. The guy worked cheap because he liked swinging in the wind, and while he was up there was about a fifteen minute pause after the installation before he started down. I wondered what he was doing until I saw wisps of smoke...



Everything is iced today but I walked around the house trying to get a good line between the trees. Luckily all of the main Portland towers are between 202 and 204 degrees. It's too slick to climb the bank behind my house but it looks like it might turn out to be the best shot if I put a mast up there and carefully aim at 203 degrees. Amazing how the prospects change in just a few feet one way or another.


This is a doable thing. It's just like me to ignore the problem until the first snow and ice storm rolls in.
 

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krs,


A quick data point to help with your decision. I have a Winegard 7696P, which is shorter than the 7698 (about 110" long), but the same design. On Monday night, it survived 50 mph gusts off a pole that is braced 10' down from the antenna. So, that model antenna appears to handle a wind load pretty well. It also seems to be working out well otherwise. I have a pretty tough signal at my house, having two 100' firs across the street from me that I have to point through and then some hills beyond that.
 

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I would not rule out the VHF bands right now. The FCC is planning to (according to their own website) move TV back to VHF, to make more room for iPhones and such.


Check out their website tomorrow, after the announcements:
http://www.fcc.gov/
 
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