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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 4:08 am 
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Location: 08033 Cherry Hill Jersey
Quote:
This is being made far too complicated. String up a wire dipole for which ever band you want to operate, feed it with 50 ohm coax and get on the air.


From a newbie standpoint, this was my first antenna. 1/2 wave 20m dipole due to space restrictions. It was sort of sloping, with ladder line to a balun, then coax. It looked horrible, like a sad, wilting Charlie brown Christmas Tree.

I was stunned at the performance by something that cost only a few bucks.

Bill is right, keep it simple and just
Get on the air.

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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 1:21 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Beaver Falls, PA. USA
Would an older transceiver like the HW-101 properly tune a G5RV without an antenna tuner? I am going to put one up, as soon as the weather improves.

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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 1:42 pm 
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Tim Tress wrote:
Would an older transceiver like the HW-101 properly tune a G5RV without an antenna tuner? I am going to put one up, as soon as the weather improves.
Quote:
A transmatch (antenna tuner) is not required to use this antenna near its nominal design frequency of 14 MHz, and judicious length adjustments can sometimes include one other frequency band. All other frequencies require a transmatch.[7][12]. There are many variants of the G5RV antenna. Two variations of the G5RV design, called ZS6BKW and W0BTU, can match several more amateur bands between 3.5–28 MHz without a transmatch.
Wikipedia.

http://www.w0btu.com/g5rv_antenna.html

Curtis Eickerman

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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 2:08 pm 
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Joined: Aug Mon 09, 2010 2:57 am
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Location: York PA.
majoco wrote:
Do away with coax cable! Open wire feeder fed from the balanced output of your shack tuner and all is good - just what was done in the 50's - the tuner then tunes the antenna and the feeder - you can't make 50ohm coax into anything else with a tuner - you may end up getting a very large voltage node somewhere down the coax and - poof.

+1 Martin! A Center Fed Zepp with 450 ohm feedline and a nice transmatch will give you multi-band capability with one antenna.

There are two drawbacks though (which I think are minor)

First, the lobes can get a bit weird the further you get from your lowest frequency. My CFZ is cut for 40M. It works well on 40, 30, 20, and 17M. Not so well on 12M. A friend of mine who has had a pair of CFZs at his QTH for years has observed this also. I've found my coax fed 160M INV-L used with an UNUN hears better on 12M than my CFZ.

Second, if you elect to buy a modern no-tune radio, then by using an external transmatch you will loose the push button tuning capability -- you can't use the on-board auto-tuner with an external transmatch.

I use a Heathkit SA-2060 tuner with my CFZ. They are not cheap, but they are good.

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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 2:15 pm 
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Joined: Aug Mon 09, 2010 2:57 am
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Location: York PA.
Tim Tress wrote:
Would an older transceiver like the HW-101 properly tune a G5RV without an antenna tuner? I am going to put one up, as soon as the weather improves.


Go to the W0BTU web site that Curtis referenced. Note the last paragraph:

"A much better alternative to any of these three antenna designs is running the open-wire line from the center of a dipole all the way to a balanced antenna tuner, which was recommended by Louis Varney, G5RV himself. That antenna will work on ANY band from 80 through 10 meters. (And that's what I eventually did with this improved antenna design here at my QTH.)"

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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 2:27 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 316
Location: Michigan, 49712 - SC, 29577
Also see the ZS6BKW variant of the G5RV. I've had good success with one at my vacation cabin.

http://www.w5dxp.com/ZS6BKW80/ZS6BKW80.HTM


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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 3:48 pm 
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Posts: 8743
Location: Beaver Falls, PA. USA
I have the WA2NAN True Talk antenna, which comes with its own coax feedline. If I do need to use a tuner, it is no problem, as I have a couple of nice ones.

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 Post subject: Re: Transmatch?
PostPosted: Feb Wed 14, 2018 4:17 pm 
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Joined: Aug Thu 20, 2015 3:09 pm
Posts: 1123
Location: Albion, CA, USA, 95410
majoco wrote:
Do away with coax cable! Open wire feeder fed from the balanced output of your shack tuner and all is good - just what was done in the 50's - the tuner then tunes the antenna and the feeder - you can't make 50ohm coax into anything else with a tuner - you may end up getting a very large voltage node somewhere down the coax and - poof.


+1

Multi-band antennas are best fed with balanced line. Coax is lossy with high SWR, balanced feed line is not. I have fooled with a number of antennas and find that my horizontal loop fed with 450 ohm ladder line tunes up sweet and outperforms all the others I have tried.

In the beginning I was (like most new hams) obsessed with being able to work all bands. Since then I have discovered that I mostly work three bands, 80, 40 and 20 meters. With the solar cycle where it is (and will be for a while) openings on the higher bands are rare anyway.


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