Best Matching Method

[WA2SI]

I asked this as part of a different post but it may have gotten "lost in the sauce."

What are your opinions re. the most efficient/low loss way to feed a non-resonant single band antenna? (I.e. Gamma, Beta, Tapped-coil, Transmatch in the shack, etc.)

As always, take care es...

Vy 73 de Bert
WA2SI

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[wavrider]

Matching network at the feedpoint.

NO coax loss due to high VSWR IE reflected power.

 

[Captain Kilowatt]

" non-resonant single band antenna" Please describe this antenna as the configuration may determine the best answer. One question, if it is a single band antenna why can it not be resonant?

 

[WA2SI]

" non-resonant single band antenna" Please describe this antenna as the configuration may determine the best answer. One question, if it is a single band antenna why can it not be resonant?

Hi CK,

Easy, if it were a resonant antenna, it'd be, say... a half-wave dipole. With all the talk of 5/8ths (0.625L) wave and 0.624L antennas, I'd like some opinions on feeding a non-resonant "gain" antenna. My personal choice being an EDZ, of course, but the 20-meter EDZ I'm using now also doubles as a multiband antenna and is fed w/600 Ohm open-wire ladder-line with a transmatch. Thus it's only and EDZ on 20!

I think a lot of folks who have sufficient space between the trees on their property may be overlooking a very simple and cheap DX antenna in favor of some possibly inferior yet more expensive commercial offerings.

A full-wave loop is another example of a "gain" antenna that can be matched in a variety of fashions. There's a 2:1 BalUn, a 1/4L matching stub, or even just changing the shape of the loop itself. (Square vs. Delta vs. Rectangular, etc.)

73, Bert

 

[wavrider]

Let's narrow this down to a specific type of antenna you want to impedance match.

Specific question would receive answers instead of a general question requiring more information for a reply.

With that said what type of antenna are you wanting to experiment with the matching network?

 

[WA2SI]

Let's narrow this down to a specific type of antenna you want to impedance match.

Specific question would receive answers instead of a general question requiring more information for a reply.

With that said what type of antenna are you wanting to experiment with the matching network?

Ok, I kinda wanted it to be a discussion of various favorite matching methods rather than a question re. a specific antenna. I thought it would be a nice learning thread for all as well a good discussion topic illustrating a nice cheap alternative for those seeking a "gain" antenna. (i.e. a $100+ commercial 5/8L vertical vs. An better performing EDZ one could build for about $20.

How about that for a specific antenna... A 5/8L vertical. (Really just and end-fed Zepp?) There's our starting point then, a 5/8L (or 0.64L) vertical. Really the type of non-resonant antenna was unimportant. The favored method of impedance matching was the target subject, no specifics necessary.

73, Bert
WA2SI

P.S. I favor the ladder-line/transmatch method too but am intrigued by the 1/ matching stub.



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[wavrider]

Thanks for the reply.

5/8 wl end fed?

Tapped inductor, lowers the impedance down to 50 ohm's more or less.

Now a gain antenna that requires no input matching network 3/2 dipole.

3/4 wl on each leg presents a nice 50 ohm impedance and gives gain over a simple dipole.

Prime example is the 40 meter dipole being used on 15 meters, great DX antenna if installed at height.

 

[Kamikaze]

An EDZ is 10/8ths wave long. Longer lengths may match easier but the broadside pattern goes away.

Best matching depends on if it will be used on other bands.

#1 would be a remote adjustable network at the feedpoint with junk cordless screwdriver drives to the variable cap(s) and or inductors.

A close second would be ladder line not window line and a good balanced coupler near or in the shack.

A 40 meter EDZ will work OK on 160 meters if conductor sizes and matching components are large enough.

 

[WA2SI]

An EDZ is 10/8ths wave long. Longer lengths may match easier but the broadside pattern goes away.

Best matching depends on if it will be used on other bands.

#1 would be a remote adjustable network at the feedpoint with junk cordless screwdriver drives to the variable cap(s) and or inductors.

A close second would be ladder line not window line and a good balanced coupler near or in the shack.

A 40 meter EDZ will work OK on 160 meters if conductor sizes and matching components are large enough.

Hi Kamikaze,

Thanks for the reply. I like your ideas. I currently use an 88' doublet (20m EDZ) fed with ladder line and a tuner for 10 through 80. As expected, it plays like a gangbuster on 20.

My thought for newly licensed Techs who'd like to jump on the phone portion of 10m, a 44' EDZ would be a great inexpensive DX antenna. Rather than spend $100+ for a commercial 1/2L or 5/8L vertical, a 10m EDZ with a 1/4L matching section can be constructed for abt $20 to $30.

Vy 73 de Bert
WA2SI

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[Kamikaze]

Hi Bert,

Getting on the air cheaply seems to be much less important than it was years ago. The new guys I hear appear to be having the most fun buying and trading up. Of course there are always exceptions. Thrift is a time honored ham tradition!

It will take a few more components than a 1/4 wave matching section to match a simple 10 meter EDZ. The 1/4 wave sections are great for impedance matching when the load is resonant but not 50 ohms. The EDZ is of course not resonant.

Antenna resonance is waaay over rated. Having a requirement that a wire antenna be resonant excludes a lot of very good designs.

I know you already are aware of the above. Just some editorial.

73,
The Devine Wind. Also known as KAMIKAZE since 1975.

 

[WA2SI]

Hi agn, Kamikaze:

Very well summarized! When I was abt 13 or so, my parents bought me a pair of GE 100 mW Part 15 h/t's that were crystallized for CB channels, 14 and 20. (27.2050 MHz or Ch. 20 was the local ragchew freq back then,.circa 1975.) I gave one to my best friend down the block and we enjoyed relatively QRM-free comms most night. When I started to hear stations farther away, I wanted to increase my range.

After a little research, I ended up constructing a 1/2L dipole made from some spare 16 gauge speaker wire and some store bought RF-58AU "type" coax with center/end insulators. I think the entire "project" cost me about $12 +/- along with some quick and dirty soldering lessons from Dad. Well, I replaced the h/t's telescopic whip with the coax fed dipole hung in a tree and the band literally came alive! There is an inherent sense of achievement in making something that performs better than its commercial counterpart cheaply. I suppose that is where I was heading with this thread - hihi. Don't get me wrong, feel free to leave a top-of-the-line M2 under my Christmas tree. ;-)

As always, take care es...

Vy73 de Bert
WA2SI

P.S. That old h/t also transmitted MCW. Legal on 27 MHz using a Part 15 device. So that's when the "bug" first hit me - hihi.

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[wavrider]

I agree on the feeling of accomplishment that comes from constructing and building one's own antenna or equipment.

Marconi ( the real Marconi ) would probably roll over if he had any idea of how many ham's are buying wire antennas instead of rolling their own.

The best part of the hobby ( to me anyway) is experimenting and testing home brew equipment, whether it is antenna's or other associated equipment.

With computer modeling and the WWW information is so readily available it is easy to find plans, dimensions for any type of antenna that one would want to build or experiment with.

 

[BOOTY MONSTER]

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