Will a transformer improve reception or compensate for antenna height? Is a transformer for a wire antenna only?
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Antenna receiver transformers
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jim202
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Before going any further with the thread here, I would suggest that you do some homework on antennas, their construction and use for what frequency range.
ka3jjz
Wiki Admin Emeritus
Not a particularly great answer, let's try something else;
Short the answer to your questions really has to do with what transformers are used for in an antenna system. Some kinds of transformers change an unbalanced feed (those that use coax cable, for example) to a balanced feed (think of ladder line). Others are used to isolate the antenna from the feedline (very useful in transmitting applications), change one impedance to another or even isolate noise producing currents off a feedline.
This is a very broad description, and whole books of theory have been written on this subject. These are not just for wire antennas - there are various kinds of amateur verticals, and even some beams, that use transformers (of one kind or another - there are MANY types).
When talking about transformers, don't mix 'antenna' and 'receiver' - there are specific types for each, and each has a very different function. A 'receiver' transformer is most likely to be thought of as being part of the power supply, and has nothing to do with the RF characteristics of an antenna.
Mike
Short the answer to your questions really has to do with what transformers are used for in an antenna system. Some kinds of transformers change an unbalanced feed (those that use coax cable, for example) to a balanced feed (think of ladder line). Others are used to isolate the antenna from the feedline (very useful in transmitting applications), change one impedance to another or even isolate noise producing currents off a feedline.
This is a very broad description, and whole books of theory have been written on this subject. These are not just for wire antennas - there are various kinds of amateur verticals, and even some beams, that use transformers (of one kind or another - there are MANY types).
When talking about transformers, don't mix 'antenna' and 'receiver' - there are specific types for each, and each has a very different function. A 'receiver' transformer is most likely to be thought of as being part of the power supply, and has nothing to do with the RF characteristics of an antenna.
Mike
I guess my question was too general. I was mainly wondering if there was any type of transformer that would improve the reception for my R7100 from my D3000N antenna that will be about 35' from the ground.
ka3jjz
Wiki Admin Emeritus
Nope - at these frequencies, the antenna type, height above ground, frequency and many other factors influence how well you receive a particular signal.
Frequencies above 30 Mhz are basically line of sight (there are conditions that break this rule) so there's a certain amount of physics involved here. A general rule you can use is the higher the frequency, the shorter the distance it will travel, within certain limits (as mentioned above).
Mike
Frequencies above 30 Mhz are basically line of sight (there are conditions that break this rule) so there's a certain amount of physics involved here. A general rule you can use is the higher the frequency, the shorter the distance it will travel, within certain limits (as mentioned above).
Mike
majoco
Stirrer
A D3000N is a wideband discone non-directional antenna. The designer would have made the antenna a match for 50ohms which is what your R7100 is designed to accept. No transformer or balun will improve anything.
Mike has said everything else that I would add.
Mike has said everything else that I would add.
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