Author Topic: Commercial Rabbit Ears, am I missing something here?  (Read 1436 times)

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Offline rwgast_lowlevellogicdesinTopic starter

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Commercial Rabbit Ears, am I missing something here?
« on: December 31, 2016, 10:42:07 pm »
So I was at a dollar store yesterday and they had rabbit ears with a UHF loop for a buck! I bought 4 for a Doppler project. I opened up the bottom and the loop is just wired in parallel. OK a loop and a dipole are obviously different designs so isn't there a big chance of the signals cancelling each other and that kind of mess? I would think there should be at least a diplexer between the dipole and loop, in general do most passive rabbit ears with loop just wire the elements in parallel and call it a day or are these just extremely cheap?

Offline retrolefty

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Re: Commercial Rabbit Ears, am I missing something here?
« Reply #1 on: December 31, 2016, 10:57:36 pm »
Just the cheapest minimalist approach that may or may not work depending on the signal strength of the frequency/channel of interest. Next step up would use a variable C or switched C to 'tune' the antenna to the frequency/channel of interest.
 

Offline SeanB

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Re: Commercial Rabbit Ears, am I missing something here?
« Reply #2 on: January 01, 2017, 09:52:11 am »
They are designed for use in a high signal strength area, and in many cases you will get better reception in the TV set by simply cutting the cable off right at the base of the unit, and taping the cheap and nasty coax cable they use to the wall, where it will pick up enough signal. the loop is basically an inductor across the dipole ( well, sort of) and does provide some lower loss at some band, and at some it is a magnetic loop, but the biggest pick up is the flylead.

There are quite a few cases where i had to replace all the RF interconnects between the antenna and the TV set with better quality ccable and decent connectors, as there was visible ghosting, caused by the signal from the external antenna being delayed by the downlead, and the cheap connector wires picking up enough signal in the house to be the stronger signal in some cases, though with bad multipath reflections.

TLDR, rabbit ears work if you can look out the window and see the transmitter unaided.
 


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