Re: 43' Vertical

Posted by Julius Fazekas n2wn on Mar 16, 2009; 1:48pm
URL: http://elecraft.85.s1.nabble.com/43-Vertical-and-the-K2-tuner-tp2481408p2486119.html

Hi Roy,

There's no reason to cut resonant radials if they will be on the ground or buried. You gain nothing and waste time and money. If they were raised then you should do what you suggest.

The radials should be dense near the base of the antenna, that is where the current is highest and the ground lose is most profound.

You're in an area that typically has better soil conditions than some of us have. I suspect you could have a great signal with 30 to 36 radials, versus 64 where you might only pick up a half dB.

There have been a number of great studies published in QEX and NCJ in the past couple of years. Well worth reading before hand.

Rudy, N6LF, has posted his studies online at http://www.antennasbyn6lf.com/design_of_radial_ground_systems/

Well worth reading to save time and effort.

You should be able to do what you suggest with the ladder line. You may have to trim the 30M element a few times, or better yet, tune it with a cap at the base to bring it to resonance.
If you're an ARRL member search for: "An Efficient Multiband Vertical for 160 through 20 Meters" which uses a similar approach.

I use stranded 18 AWG for my radials and they work well. I know folks using smaller gauge with higher power too. It just depends on how many and how much traffic you have near them (from a mechanical perspective).

Any vertical that is base loaded is the least efficient, stay away from those if possible. I've been through this and the difference is like night and day.

Good luck with the build!

73,
Julius

Roy Davis wrote

I am in the process of building a 40 meter  1/4 wave vertical.  My hopes for
this antenna is that when the conditions favor vertical antennas as opposed
to a dipole, that it will help me to work in to the far East as my dipole
does not.  I understand that a dense radial field is necessary for good
results and that the far field which I have no control is a factor.  My plan
is to use 64 insulated radials as close to resonant as possible, buried a
few inches below soil.  I thought of using ladder line as the radiator,
cutting one side for 40 and the other for 30 meters supported by a catenary
line.  If that does not prove out, I have aluminum tubing which to make a
1/4 wave for 40.  Anyone have any comments pro or con for my project?  So
far, I have the pipe in the ground, and the radials cut ready to attach to
the DX Engineering radial plate.

I have K3 #1366 and really like this radio.  A lot to offer in such a small
package.

73.

Roy Davis - WK4Y
Richmond VA


----- Original Message -----
From: "WILLIS COOKE" <[e-mail]>
To: "James Apple" <[e-mail]>; <[e-mail]>; "Darwin,
Keith" <[e-mail]>
Sent: Sunday, March 15, 2009 6:12 PM
Subject: Re: [Elecraft] 43' Vertical and the K2 tuner


>
> Keith, in theory the 5/8 vertical should be 3 db stronger than the 1/4
> vertical installed in the same position.  A ground plane on top of a house
> could easily be as good or better than a 5/8 wave ground mounted and
> radiating into the side of the house and some trees.  3 db is about 1/2 S
> unit anyway, so it will not be a large difference.  You are correct about
> the far field conductivity being very important in how a vertical antenna
> will play, whether it is mounted on top of a tower or house or ground
> mounted.  The radials are most important to bring up the radiation
> efficiency, the far field is most important for the take off angle.
>
> The 43 foot vertical will have a higher radiation resistance than a
> shorter vertical for all bands, making it easier to get the efficiency up.
> It will still be lower than 50 ohms for 160, 80 and 60 meters, about 50
> ohms for 40 and higher for the upper frequencies.  I don't have one
> because I have a 3 element SteppIR with the 30/40 dipole trombone at 21
> meters.  I don't think the 43 foot vertical will play as well, but they do
> play well.  I have worked several of the Zero-Five offering and they all
> play well.  I would expect the DXE, Hygain and MFJ to play well also, but
> they are newer and I don't know anyone who has one.  All still need a good
> ground plane and will play much better with conductive soil.
>
> Willis 'Cookie' Cooke
> K5EWJ
>
>
> --- On Sun, 3/15/09, Darwin, Keith <[e-mail]> wrote:
>
>> From: Darwin, Keith <[e-mail]>
>> Subject: Re: [Elecraft] 43' Vertical and the K2 tuner
>> To: "James Apple" <[e-mail]>, [e-mail]
>> Date: Sunday, March 15, 2009, 2:39 PM
>> A few years ago, I was really on the 5/8 vertical bandwagon.
>>  I thought it was the cat's meow.  The problem was that
>> real world A/B testing did NOT show it to be any better than
>> a 1/4 wave vert.
>>
>> I had a 5/8 wave vert for 15 meters.  Ground mounted over
>> 16 radials.  An ATU at the base took care of the small
>> impedance mismatch and RG-213 carried the signal to the rig.
>>  Hot stuff - or so I thought.
>>
>> I also had a 1/4 wave ground plane (4 radials) on the roof
>> of my single story house.  It was fed with RG-58.  I spent a
>> lot of time with an A/B switch listening to both antennas.
>> You'd think the 5/8 with it's mondo low-angle
>> radiation pattern would walk all over the 1/4 wave but it
>> DID NOT.  DX signals as the band was just opening or closing
>> were sometimes stronger on the 5/8, other times on the 1/4.
>> There was no clear winner.
>>
>> It was years before I found the answer.
>>
>> Apparently, that wonderful low angle radiation that we want
>> out of the 5/8 wave antenna depends HEAVILY on the ground
>> conductivity many, many wavelengths away from the antenna.
>> Far out of the reach of any ground radial system, poor soil
>> conductivity is sucking the low angle radiation down to near
>> zero.  Sure, over salt water it is fabulous, but for the
>> vast majority, it just doesn't pan out that way.
>>
>> So, for "normal" soil, it seems the best height
>> is something less than 1/2 wave.
>>
>> I run a 33' vertical with a Hustler 80M resonator on
>> top.  It resonates on 80 and 40 and does pretty well on
>> those two bands.  It also delivers the goods on 30 meters
>> due to the remote tuner.  On 20 meters and higher it
>> isn't really all that impressive.
>>
>> - Keith N1AS -
>> - K3 711 -
>>
>>
>> -----Original Message-----
>> From: [e-mail] on behalf of James
>> Apple
>> Sent: Sun 3/15/2009 9:26 AM
>> To: [e-mail]
>> Subject: [Elecraft] 43' Vertical and the K2 tuner
>>
>> After the ice storm of 2009, I'm looking for an new
>> antenna.  I've
>> been considering the 43' verticals by DXE,HyGain and
>> MFJ.  But I'm not
>> sure if my K2 tuner will have the range needed.  The DXE
>> site has a
>> warning about internal tuners.  Anyone using a K2 and a
>> 43' vertical ?
>> how's it play ?
>>
>> Thanks in Advance
>>
>> - Jim (WB1DOG)
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