Original OTA Build-It-Yourself Antennas & Gear (Now Closed)

[dsspredator]

I might try this just for fun:



http://uhfhdtvantenna.blogspot.com/

[stampeder]

I find that photo of the home-grown 4-Bay in the attic quite troubling because of all the multipath interference that will happen from the huge amounts of foil duct wrap, let alone any other metal up there!

[rickleg]

I tried the one recommended by dsspredator in post #76.

I have the same results as my 130$ Radio-Shack. I can get CBC, SRC and the 2 PBS. Nothing more, nothing less. The only difference is that this one cost me 0$.

[roger1818]

rickleg,

I am not sure which antenna you have from Radio Shack, but it is probably a combo VHF/UHF/FM antenna. Bowtie antennas are UHF antennas and typically won't receive VHF (or FM) very well (the CM4228 is the exception to this rule). Once the analog shutdown is complete, some stations will be moving their digital broadcast to VHF and you will want something to pull them in.

[rickleg]

Roger1818,
you are right. I just wanted to see if that handcraft antenna would work and the surprise for me is that it is working as good as my Radio-Shack (which is a fm/VHF/UHF).
My goal is to go with a Channel Master 4228 if I can find a way (or the courage) to mount it on the roof.

[HasanMurtaza]

I built a helical antenna using a 6" sonotube from Home Depot, and#18 guage wire wrapped in a helix with turns spaced 4" apart. A reflector plate was made from bristol board (from a placard used in some protest long ago) covered in aluminum foil.

The whole thing was 7 feet long, and gave excellent reception, picking up CBC, CTV, 25.1, and Buffalos CW (23.1). Analog reception was perfect on all channels.

[Dante1]

HasanMurtaza: Do you have pictures?

[green6866]

dsspredator thanks.

I built one of these doityerselfers in about 30 minutes from scrap around my shop while my wife was putting the baby to bed. She had a good laugh when she saw it. She's still smiling; but now because she watched American Idol in HD.

I have an LG LCD with a built in ATSC tuner. With the amplified NexXtech antenna from "The S" I was pulling in 23-1 (which comes in when the antenna power is off) and 43-1, 43-2 and 43-3 sometimes.

When I hooked up the homemade bowtie I got 9 digital stations on my first scan. Yesterday I took it apart and sanded the finish off the hangers, which I had forgotten to do, and scanned 12 when I reconnected.

I am in Oakville at Bronte and Dundas and I get: 5, 6, 7, 9, and 11 on the NexXtech and 17, 19, 23, 25, 29, 36, 41, 47, 49, 52, 57 and a weak 69 analog.
Digitally I get those listed below with the antenna sitting in the mainfloor family room. I can't wait to stick it in the attic and see what I'll be getting; Hopefully more Toronto stations.
2-1
4-1
5-1
7-1
23-1
29-1
29-2
43-1
43-2
43-3
49-1 poor
49-2 poor

Questions: The scrap I used for the reflector part was 30" x 14". Would a wider reflector make a difference? Could I make another one and aim one at TO and the other at Buffalo on one cable instead of using a rotor?
Cost $0
Thanks again.

[roger1818]

Originally Posted by green6866

Could I make another one and aim one at TO and the other at Buffalo on one cable instead of using a rotor?

Yes you can, but you may not be happy with the results.

Using a splitter or signal combiner will reduce the signal strength from each antenna by more than half. You also might run into multipath problems if one antenna is picking up signals intended to be received by the other antenna. You might want to give it a try though as it doesn't cost very much and it might work for you.

Another option is to use an A/B switch to select the antenna you want, but this isn't much different than using a rotor.

(see Merging feedlines for a technical explenation)

[stampeder]

I'm not sure if I've mentioned this on DHC ever before, but there was a guy who rigged up a rope and pulley system at his cottage that moved his antenna back and forth as he sat in front of the TV. Pulling one rope about 2 feet swung it to one city, and pulling the other rope all the way outwards swung it to the other city. It worked perfectly!

Somebody might be able to rig up something mechanically similar, or an electrical method - if so please post it here!

[99gecko]

good work green6866!!

in addtion to roger's points, be aware that placing your masterpiece in the attic might change your results in ways you don't expect (even with the increase in elevation).
In the family room you might be getting good results through a window/patio
door?
In the attic you will have to deal with:
1) a potentialy longer RG6 run - increased signal loss
2) attentuation from roofing materials - shingles, wood etc.
3) IF your house is older and has mature trees, the leaf canopy will be higher - more of an issue in the summer.

edit: re: stampeder's post - and post pictures!!!!

[green6866]

I was wondering if there would be a huge difference with a different reflector. I used a similar mesh that was pictured earlier in this thread.
The results are pretty much the same. My LG LCD doesn't show percentages, but rather a bar with 'bad normal good'.
I actually built a second one with aluminum wire instead of coat hangers.
I hooked the two together to try for an 8-bay and the results stayed the same. Am I overlooking something? I wired right to right and left to left.

In answer to 99gecko--the house is 2 years old (small tree-twig really) , the family room is on the opposite side of the house from the signal...so no window.

I'll try to post a picture....

[green6866]

I checked out the link in Stampeder's post #75 and realized that you need 2 baluns and a splitter turned around as a combiner (a wye?). I got good results last night. 27 channels--13 of those digital here in Oakville.

I hope the Canadian stations plan to step up their power a little in the future.
I'll go look for a thread on future plans or public input or something.

[mnx]

Originally Posted by Yaamon

mnx, elevation(height) of where the antenna is positioned is one of the most important requirements in getting good reception.

The key into receiving strong and stable signals you need elevation and a pretty clear view of where the antenna is pointing towards.

Generally you will not get good results on the ground floor onless you live on right along a lake.

Good luck.

I finally borrowed a ladder so I could get up on the roof. Here are the results.

5-1 CBLT 10/10
9-1 CFTO 6/10
15-1 CKXT 5/10
25-1 CBLFT 7/10
57-1 CITY 3/10

can detect 23-1 and 43-1 but the signal is too week 99% of the time to get a picture.

I got the antenna as high as possible (probably about 5ft above the peak of the roof). My cable length was 62 feet (a 50ft cable joined with a 12ft cable indoors).

Wouldn't mind hearing your thoughts. I snapped a few pictures while I was up there.

http://mnx.ca/1.jpg -----> view of antenna
http://mnx.ca/2.jpg ------> view of buffalo/grand island
http://mnx.ca/3.jpg ------> my 4 bay homebuilt antenna


Couple quick questions...

1) I'm only interested in buying a channel master if it's going to blow my current results out of the water. (eg. get everything from buffalo). Looking at others results I'm a little puzzled that my buffalo reception is so poor while my Toronto reception is so good... Are those apartment buildings getting in the way? Do you think a 4228 would be necessary to get Mytv 49-1 and NBC 2-1? If I have a 4228 will I need to attenuate the signal (since CBC is already 10/10)?

2) Will I still be able to get the Toronto stations while being aimed at Buffalo, or am I going to need a rotor? (or will this depend on whether I end of with a CM 4221 or 4228)?

Thanks!

mnx

[Yaamon]

mnx a few answers and suggestions.

First your antenna is not built properly, The bows are not evenly spaced like a 4 bay(4221).

Just looking between the top two bows they looks like one is almost touching each other.

Then between two sets of bows looks like there is two much space too. Not sure if it has a effect but the bow looks like it bent upwards. On the channel master they are all flat.

If you are making a home made 4 bay you have to do it right. If not the results you get will be poor. Now seeing your antenna Iam not at all suprised at your results.

The picture with the antenna facing Buffalo/Grand Island, because you took the picture from a lower angle Iam sure if it was from right behind it would show that the apartment is in the path of the antenna.

Also just because cbc is at 10 using a 4228 should not cause any overload. Every tuner has a agc gain control and if you are not using a preamp or amp your tuner should handle the additional signal fine.

From where you are a 4221 or 4228 will be tight to get all the stations properly. Because you dont have a clear view a rotor might be better to fine tune some of the stations as you might be also dealing with some reflected signals.

Good luck.