mlord,


did you post any pics of your home-built tilter, thanks

mlord, did you post any pics of your home-built tilter, thanks
Mmm.. I think the only possibly okay photo I have of it is this one:

[deleted -- better image below now]

The mast from the rotor extends straight up to the mid point of the antenna. The antenna is on a separate mast, hinged at the midpoint where it attaches to the mast from the rotor.

The tilt gets manually adjusted by removing a bolt from the bottom adjustment rail, repositioning it, and reinserting the bolt again.

I have parts and plans to motorize it, but that hasn't happened yet.

The blob behind the antenna is a scrap of eavestrough downspout, acting as a weatherproof housing for the preamp and 2:1 combiner.

Cheers

thanks, thats sharp! so now I see the bottom adjustable brace is very supportive...

what can we use as a hinge, can a simple bolt system be used thru the two pipes, or is that an oversimplification!

http://www.digitalhome.ca/forum/picture.php?albumid=45&pictureid=1119

The "hinge" is just a couple of T-brackets: bolted to the antenna mast (left), and attached to the tower/rotor mast (right) via a single bolt/nut, so it can pivot freely (yet securely).

And to answer the obvious unasked question: Yes, it is absolutely rigid, with zero flex even when subjected to very high winds.

Cheers

mlord,


Thanks, I just saw your updated pic, an antenna hobbyist and photographer, great picture. I like that simplicity and functionality. I look forward to your motorized version.

I am near a very large expanse of water, and may use this idea also.

What masting, and piping material did you use with this set-up?

thanks

Both the antenna mast, and the tower/rotor mast, are from a chopped up section of chainlink fence toprail from H.D.

I could have used aluminium for the antenna mast portion (less weight), but didn't. :)

Cheers

This isnt a tilt as you are descibing, but Ive found that rotating the antenna from the straight up and down position may have benefits as well.

Particularly using the Radio Shack 1880 indoor antenna. (Others have noticed this too).

Here is a shot of the tilt which Ive found to be of greatest benefit at least at this location.

http://i302.photobucket.com/albums/nn88/EscapeVelo/IMG_0808.jpg

Ive also seen the focus mounted double bow on the Channel Master 4251 Parabolic that was rotated at a similar angle.

A situation came up in which a person up near the top of a high rise wants stations from behind the building (through it) yet the building does not seem to allow good signal penetration from that direction.

A solution is to aim forward (out the front window away from the centre of the building) to hopefully pick up the rearward stations using reflections from nearby buildings.

This might require tilting to go along with standard azimuth aiming. My advice was that the person mount their ZSS-clone on a camera tripod so that left-right sweeps could be done along with easy adjustments to the tilt since neaby buildings come in all sorts of heights and angles. I hope it works out.

Just another example of tilting for the books. :)

I have noticed that I am able to pick up the weakest stations on the CN tower (CITY, 2.2kW I think, and OMNI2, can't find the exact info) with a little bit of tilt from my Kitchener, ON, home. This is with a ******** ANT-2109 with a cheap-ass no-name balun and a CM-7777 preamp. Tilt *definitely* impacts reception.

stampeder,
I've just read your post #47 and the one above by EscapeVelocity describing rotating the antenna (aka skew). Something just occurred to me after reading them together.

Since OTA transmissions are polarized rf signals, I recall from my physics courses that the characterization of polarized electromagnetic waves reflecting off (especially) non-perpendicular planar surfaces can change significantly and measurably.

Consequently it would seem reasonable to suggest that playing with the skew (rotation), as well as the tilt, could be in order when attempting to capture reflected signals.

Do you (or anyone members for that matter) have any real world testing or empirical experiences to support/reject this hypothesis?

cheers.

I think you might want to post the topic into the Antenna Research & Development forum but in my own experience the very horizontal nature of TV reception means that in almost all situations skewing an outdoor antenna reduces signal.

With rabbit ears being used indoors the situation is quite different, so the odds of reflected signals not in the original plane are high and thus the eventual rabbit ears configuration might not be horizontal at all.

I have my antenna indoors as I was not able to properly run a ground for it outside condo life.
My receptions from a bounce off of three new towers just put up over the last couple of years in New Westminster.

http://www.earthcam.net/users2/interface.php?i=0&id=1952&projectid=1252&clientid=913&tab=default

A little aiming in a left or right from the buildings changes all signal levels as the three stations here for me are actually being broadcast from behind me.
I found a place where all three come in with good locks a loss of signal for BCTV and CBC how ever CTV is the best gain, luckly all three lock fine in this placement. As I only get half the hieght of the new buildings to aim at I did try tilting and lost all signal ( tilting did not effect the reception of KVOS or KBCB from the usa as I aiming basicly South ), so with all the different rotations and tiltings I have tried it remains for me to be best having the antenna upright parralell to the towers.

99gecko,

Indeed, especially indoors, polarization can be skewed, thus the adjustability of the ole Rabbit Ears in altitude and azimuth. Analog signals this could be seen better on screen....but you had to know what you were doing and were about. Otherwise it could just seem like voodoo.

Ive also seen a similar skew on a huge old parabolic Channel Master 4251...over at the Tribute Page.

Look for the picture titled....

Robert Eder's 4251/3617B "Dream" outfit (http://www.rocketroberts.com/cm4251/cm4251.htm)

New member drh9 mounted his DIY Channel 41 Yagi onto a satellite dish tilt mount on a J-pole:

http://www.digitalhome.ca/forum/album.php?albumid=375&pictureid=1673

I'm in a deep fringe area (north of oshawa) with no LOS (and no pre-amp). I spaced out the bottom of my cm 4228hd about 1 1/2 inches. It gave me about 5% increase on the few channels I pick up.

That's great to get a free signal boost like that, chunkyal. :) Did you have to loosen the upper clamp to push the lower one out like that, or was it possible without doing that?

Continued from the Mississauga reception thread:I noticed my antenna is now tilted horizontally about 10 degrees. Could this be it? I don't understand. How can my tower be tilting this way? If this keeps up, my tower will be like the leaning tower of pisa within a month. Does horizontal tilt affect reception that much? I mean the antenna is still pointed in the right darn direction.i meant it was tilting sideways, not forward/up. is that bad?Having your antenna tilted off of horizontal but at the same target (like an airplane in a roll but still going forward) is not good! A very slight tilt of less than 5° will usually not show much difference but the problem is that the bad effects go way up rapidly as the tilt increases beyond that. You need to get it back to horizontal when it is safe to do that.

If you need more info on this you could read some of the Gray Hoverman threads in which members like 300ohm have computer-modeled the bad effects of non-horizontal antenna elements and reflectors.

I can agree with this. I'd look up at the antenna and it looked crooked. So I went up with a level and found the antenna out 3/8" between the top and bottom mounts. They are only about 12" apart, so it wasn't an optical illusion. This put the antenna slightly rotated when aimed at Buffalo. I shimmed plum and found 29.1 (14.1) improved by 10%. Also weak off axis channels 57.1 and 41.1 had annoying drop outs every couple of minutes. This is all but gone with a plum mast.

Thanks for that great example! The farther away the antenna is from the desired station(s) the more critical the proper antenna geometry and aim becomes.