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Analog UHF TV signal reception improvement idea

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HSter

New Member
Hi

Will the signal reception of analog TV improve by connecting several 'rabbit ear' TV antennas to form an array, (in parallel)? instead of using just one.

Thanks
 

blueroomelectronics

Well-Known Member
Analog TV broadcasts will be gone in a couple of months in the US and in 2011 in Canada.

Rabbit ears are pretty lousy, a high up Bowtie or Yagi will help.
 
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GonzoEngineer

New Member
Hi

Will the signal reception of analog TV improve by connecting several 'rabbit ear' TV antennas to form an array, (in parallel)? instead of using just one.

Thanks
Antenna design is a form of "Black Magic".....so the answer would be, yes, maybe, it depends......

What continent do you live on?
 

Sceadwian

Banned
Rabbit ears are horrible antennas. If you're having trouble with TV reception try something directional like a biquid or a yagi. A good biquad will give you 400% gain over bunny ears at the cost of it being a directional antenna, and if tuned for the center of your channel space should cover it all fairly well.
 

HSter

New Member
Analog TV broadcasts will be gone in a couple of months in the US and in 2011 in Canada.
What continent do you live on?
I live in Nigeria, West Africa. Analog TV is still widely used down here.

1. What should be the spacing between the 'elements'/individual rabbit ears? or how do i calculate this?

2. The rabbit ears have to be mounted outdoors, and i've got coax cable to wire the ant. to TV. so will this DIY balun work: File:Di...fwavebalun.png - Wikipedia, the free encyclopedia
For UHF channel 32 (f=581MHz), the coax balun is 12.9cm (approx. 5 in.). Should I make it in form of a coil?

I am receiving some signal (video and audio) but is not clear. Also at present, I am using the rabbit ear & coax transmission line without a balun.:eek:

Thanks
 
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Sceadwian

Banned
I don't know why blueroom brought up the analog vs digital, they use the same antennas =) The broadcast frequency bands aren't changing.

Give some serious thought to a directional antenna, you'd have to put it on the outside of the house due to size and you get better reception then anyways, but you'll get channels significantly stronger and from further away than with a pair of bunny ears.
 

HSter

New Member
Thanks Sceadwian. Which is the easiest to build, since I already receive some signals.
I can go out & buy one but, I prefer to learn and DIY it myself.
 

Sceadwian

Banned
I've never tried to make one for UHF before but I've been a fan of the biquad antenna design in theory over the yagi because they're easier to make.

I've attached a PDF which contains the schematics for a 2.4ghz biquad (wifi) but it has the equation for calculating the size of the elements for any frequency. It's not in English but the graphics are self explanatory.

You don't need all four elements to get a decent antenna and it'd probably take up too much space at 500mhz so just only do one element. It's supposed to have a wide bandwidth but I don't know how wide so chose the center frequency carefully.
 

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stevez

Active Member
HSter - take a look at amateur radio publications. While not the only source of information, the publications are often aimed at a broad audience (many with little experience or theoretical knowledge) and people who like to build their own stuff.

Best of luck to you.
 

bigkim100

Banned
Guys!...guys!...come on...we have a excellent opportunity to see something absolutely rediculous here....now follow my lead...

Yes, absolutely!...great idea!...now run out, and buy 1000 rabbbit ear antennas, connect them all together, and you will get 1000 times better receiption than with 1 lousy antenna....OBVIOUSLY!
BE CERTAIN TO TAKE A PICTURE OF THIS, and post it here!.


oooh ...taking advantage of 3rd world countries is soooo fun!
 
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HSter

New Member
Guys!...guys!...come on...we have a excellent opportunity to see something absolutely rediculous here....now follow my lead...

Yes, absolutely!...great idea!...now run out, and buy 1000 rabbbit ear antennas, connect them all together, and you will get 1000 times better receiption than with 1 lousy antenna....OBVIOUSLY!
BE CERTAIN TO TAKE A PICTURE OF THIS, and post it here!.


oooh ...taking advantage of 3rd world countries is soooo fun!
bigkim100 = sarcastic smart aleck, noted.
 
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HSter

New Member
My questions are:
1. Does anyone know what is the effect of thecoax balun wound in form of a coil cut to the right frequency?

2. Does anyone here know what is the way to determine separation of the elements in the design of the multi 'rabbit ear' array, in order to prevent parasitic interference?

Thanq ...
 
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HSter

New Member
Won't the effective impedance drop when similar elements are connected in parallel to form an array. Much like resistors connected in parallel?:) ...
 
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blueroomelectronics

Well-Known Member
Like I said rabbit ears won't pick up those far away stations. A bowtie can be built with little more than scrap coat hangers, tinfoil & wood (plus a balun)
 

HSter

New Member
Thanks blueroomelectronics for your response.

what do you think about the assumption above regarding effective impedance?
 
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HSter

New Member
If the above is correct, using 4 elements implies that there is no need for a balun since 300/4 = 75 ohms, the characteristic impedance of the coax transmission line. Right? :)
 
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