Homemade HDTV Antenna

[klaven66]

hi, i realize this is a cruiser/sailer forum but i'm just trying to get some help from anyone..

i made an hd antenna, if you search homemade ota i believe, antennas you will know the type i'm talking about..with the coat hangers..

i have been trying it out and never had any success with hd channels, let alone the local channels. the antenna barely made an improvement with local channels..

the other day i was playing out with auto program..the thing was scanning..it takes so long i stopped the scan at around 30%...once it stopped i pressed channel up and i was shocked to have landed on a HD channel..HD wheel of fortune on cbc..the reception was still kind of choppy so i was trying to fix it..anyway for some reason i decided to auto program scan again and since then i have not had any success finding any hd channels..anyone here know what i can do increase my chances of locating hd channels..thanks so much

[S/V_Surya]

You might try a signal booster. I have a mast antenna with signal booster as wellas rabbit ears with a built in booster. When I turn off gain nothing when I crank it up they come in. Cheap old rabbit ears seems to work better than mast antenna.

[klaven66]

thanks for respoding...that is definately a good idea i might try that

the thing that bugs me is from youtube videos or anywhere else where i found info on these homemade antenna, they simply plug the ugly thing into the back of their tv, they just lay the antenna down on the floor and boom HD channels..i live in toronto i didn't think that location was a problem for me..

i don't understand how i landed on a hd channel..when i watch tv choices are either air or cable..somehow it landed on DTV 5-1..and unless i try something different i doubt i'll land on it again

[senormechanico]

Whereas the picture quality of an HD transmission is wonderful when you can get it, there is no difference in antenna design for analog vs HD reception. The frequencies involved are the same. Your inability to grab the signal is due to insufficient signal strength and/or multipath distortion. When we used analog signals, insufficient signal strength resulted in "snow", and multipath distortion resulted in "ghosts". Digital reception with the above conditions will result in screen freeze or complete loss of the station.

Try reorienting your antenna a bit at a time and re scan the tuner.
Good luck with your project.

Steve B.
30 year retired TV/VCR technician

[Beausoleil]

klaven66,

As Steve B. said, there's no difference between a digital HD antennna and an analog antenna but the marketing hype. Can you give us any info on the antenna you built? Perhaps we can help tweak it.

FWIW - what area are you in? In most markets, the digital stations are all in the UHF band, so you can get better performance with a UHF-only antenna. The frequencies are higher, so the wavelengths are shorter and the antenna elements smaller. In other markets, some digital stations are in the upper VHF band (channels 7-13), and the antenna needs to be somewhat larger. If you're in a market with a digital station or two in the VHF-low band, then it's a bear. An antenna needed for channels 2-6 is big - the wavelengths are 54-88MHz.

[danhaun]

In an old library book on marine electronics, I found the plans for a hoop TV antenna. The length of each pole of the loop was 41 inches. I tried a bunch of variations over the years and now use this aluminum/ rubber coated conduit (home center) , I also stack the loops and use a wood dowel to make the loop but also leave a gap to keep the poles from touching. I add a transformer to provide an attachment for the coax. It works for us. We sometimes place it flat on the bimini top and sometimes just use it inside the cabin. It likes to be horizontal. The picture of the current version tells the story. If this works for you, please post.

Picture

[Fishman_Tx]

Use a standard Channel Master yagi antenna on a piece EMT for a mast, drop it in a fishing rod holder and point it toward town, voila! all you can stand.
And if you like homemade yagi's, here's one for grins:
How to build a HDTV Antenna....CHEAP!

You could mount a piece of "refrigerator" shelving or any type of heavy mesh as a back reflector, then the spacer, and then the bowties.

[anythinggoes09]

Originally Posted by danhaun

In an old library book on marine electronics, I found the plans for a hoop TV antenna. The length of each pole of the loop was 41 inches. I tried a bunch of variations over the years and now use this aluminum/ rubber coated conduit (home center) , I also stack the loops and use a wood dowel to make the loop but also leave a gap to keep the poles from touching. I add a transformer to provide an attachment for the coax. It works for us. We sometimes place it flat on the bimini top and sometimes just use it inside the cabin. It likes to be horizontal. The picture of the current version tells the story. If this works for you, please post.

Picture

danhaun,

I am very interested in your antenna and would like to make one. However I cannot understand the connections to the 2 loops. Would you plse clarify - perhaps a simple diagram would help.

Thanks,

Peter at anythinggoes09

[senormechanico]

Peter,

Imagine a rabbit ears antenna with elements curved toward each other, connected physically at the ends, but not electrically connected. Like this:
( )
Basically, a circle with one pair of curved elements connected to the balun (matching transformer) to the coaxial cable to the TV. The other ends of each element are physically connected to each other by an insulator.

[anythinggoes09]

Stev/danhaun,

I understand this concept but danhaun's photo shows 2 such loops laid one on top of the other with one tail of the the balun connected to one side of each loop. There must be another connection between the 2 loops. The photo does not show this clearly - how is this connection made.

Thanks,

Peter at anythinggoes09

[bill good]

I have added a switch to my VHF radio antenna for TV reception. Yes I know it is not the right length/polarity but it works without adding extra aerials to my boat.
Bill

[senormechanico]

Without seeing the photo, it's only a guess, but I'll bet the upper and lower elements are connected to each other at the opposite ends, i.e. elements twice as long, but folded back on themselves.
Imagine two elements as the one below, bent in a semicircle with only one end of each element connected to the balun.

_________________________________________________
_________________________________________________|

.

[danhaun]

Originally Posted by senormechanico

Peter,

Imagine a rabbit ears antenna with elements curved toward each other, connected physically at the ends, but not electrically connected. Like this:
( )
Basically, a circle with one pair of curved elements connected to the balun (matching transformer) to the coaxial cable to the TV. The other ends of each element are physically connected to each other by an insulator.

Steve is correct here. I used a short piece of wood dowel to insulate and connect the two ends and make the loop. I hope that this works for you. The two loops are not electrically connected but just wire-tied.

Dan Haun

[anythinggoes09]

Thanks for the replies. The attachement shows how I understand the connection is made with one loop laid on top ofthe other and then this assembly cable tied together. Is this correct?

Thanks,

Peter at anythinggoes09

[senormechanico]

That's correct schematicwise. One loop is folded back on itself on one side of the circle, (6 o'clock clockwise to 12 o'clock) the other is folded back on itself to complete the other half of the circle (6 o'clock counterclockwise to 12 o'clock). The balun is connected to the (for example) bottom two ends of the assembly, one end of each folded loop.