kmi8dy
Member
can you use or would a antenna tuner, on a long wire antenna work for better reception on a receiver only. i have a icom R75.
antenna tuner
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ka3jjz
Wiki Admin Emeritus
Let's start to answer this question with a little theory (just a little, promise). Insofar as receiving goes, a transmatch (antenna tuner is a very inaccurate term) can create a resonant path between the antenna, feedline and the receiver. You'll notice I included the feedline; in some cases, the feedline is actually part of the antenna itself (a common antenna where this is true is the classic Inverted L). Put simply, it can allow as much of the signal to get to the receiver as is possible (there are some losses involved but let's not get too deep into that right now)
There is some controversy as to using a transmatch with a receiver. Most say that modern receivers don't need any matching; if the wire is long enough, you're good to go without any tuning. However, there are cases where a transmatch might be helpful; for example, if the antenna is too short to be naturally resonant on a particular band, a transmatch might bring the signal up. Using a transmatch on something that is not normally an antenna - say, aluminum gutters as an example - would also be a good idea.
Now a little more theory. The term 'long wire' is one of the most misused terms that describes an antenna. A long wire can be just that - a wire that is very long. There is a very specialized kind of antenna that is called a longwire (note there is no space between the 2 words). Basically this is an antenna that is usually fairly close to the ground and is 1 wavelength long (or more) at a given frequency. The classic Beveridge and the V beam are types of longwires. You wouldn't use a transmatch with such antennas.
Generally speaking a length of 80-100 foot is sufficient for most applications. In this case, a transmatch isn't going to get you anything. However if you're stuck with, say 45 or 50 foot, yes a transmatch might help if you tune below 6 Mhz or so. Certainly a transmatch can help if you are trying to tune with gutters, or some other metallic structure that is not necessarily useful as an antenna in other circumstances
Getting a transmatch that can handle 1kw is a waste of money, unless of course you are using it for ham use running that kind of power. Even QRP (low power) transmatches would work just fine with receivers like the R75.
Mike
There is some controversy as to using a transmatch with a receiver. Most say that modern receivers don't need any matching; if the wire is long enough, you're good to go without any tuning. However, there are cases where a transmatch might be helpful; for example, if the antenna is too short to be naturally resonant on a particular band, a transmatch might bring the signal up. Using a transmatch on something that is not normally an antenna - say, aluminum gutters as an example - would also be a good idea.
Now a little more theory. The term 'long wire' is one of the most misused terms that describes an antenna. A long wire can be just that - a wire that is very long. There is a very specialized kind of antenna that is called a longwire (note there is no space between the 2 words). Basically this is an antenna that is usually fairly close to the ground and is 1 wavelength long (or more) at a given frequency. The classic Beveridge and the V beam are types of longwires. You wouldn't use a transmatch with such antennas.
Generally speaking a length of 80-100 foot is sufficient for most applications. In this case, a transmatch isn't going to get you anything. However if you're stuck with, say 45 or 50 foot, yes a transmatch might help if you tune below 6 Mhz or so. Certainly a transmatch can help if you are trying to tune with gutters, or some other metallic structure that is not necessarily useful as an antenna in other circumstances
Getting a transmatch that can handle 1kw is a waste of money, unless of course you are using it for ham use running that kind of power. Even QRP (low power) transmatches would work just fine with receivers like the R75.
Mike
The basic answer is "yes". If you already have one, go ahead and give it a try. However, don't go out and buy a tuner with, say, an SWR meter and rated for a kw unless you have a ham radio use for it. Something like a MFJ 956 would be a less expensive alternative.
Even more simple and inexpensive would be the use of just a broadband matching device like a 9:1 unun.
ka3jjz
Wiki Admin Emeritus
What is your situation, kmi? Be as complete as you can with your description...Mike
I have had success (improved reception) using passive or active tuners with antennas and random wires not specifically tuned/cut for the band I am trying to monitor. I have also had improved RX by turning a tuner off.
Experiment and enjoy!
Experiment and enjoy!
unclejed613
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i use an antenna tuner, and have a dipole that's nearly the right length for 20 meters. i say "nearly" because it's more like two random lengths of wire. one side goes around the top corners of my living room indoors, and the other side goes outside and is draped over a tree. it's an "apartment expedient" antenna. an interesting thing happens on the 40 meter band, the tuner has very little effect on incoming signals. i seem to get a couple db more when the tuner is at resonance than without the tuner. however on other bands, the tuner has a very big effect. most antenna tuners are a "T" match where the two arms are the capacitors, and the vertical is the inductor. it's a pair of series LC circuits sharing the inductor. when you tune the antenna arm you are matching the antenna impedance at a given frequency. on the other side you are matching the receiver input at the same frequency.
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