[Elecraft] 43' Vertical
Julius Fazekas n2wn
phriendly1 at yahoo.com
Mon Mar 16 11:13:35 EDT 2009
I'll back off on my comment based on Geoff's EZNEC study, you may have issues
with 30/40 dual elements.
I have used a single 40M element and remote switched in/out tuned network
for matching. This did work well, but it's not as simple as a parallel feed.
73,
Julius
Julius Fazekas n2wn wrote:
>
> 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" <wrcooke at flash.net>
>> To: "James Apple" <wb1dog at gmail.com>; <Elecraft at mailman.qth.net>;
>> "Darwin,
>> Keith" <Keith.Darwin at goodrich.com>
>> 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 <Keith.Darwin at goodrich.com> wrote:
>>>
>>>> From: Darwin, Keith <Keith.Darwin at goodrich.com>
>>>> Subject: Re: [Elecraft] 43' Vertical and the K2 tuner
>>>> To: "James Apple" <wb1dog at gmail.com>, Elecraft at mailman.qth.net
>>>> 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: elecraft-bounces at mailman.qth.net on behalf of James
>>>> Apple
>>>> Sent: Sun 3/15/2009 9:26 AM
>>>> To: Elecraft at mailman.qth.net
>>>> 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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>
>
-----
Julius Fazekas
N2WN
Tennessee Contest Group
http://www.k4ro.net/tcg/index.html
Tennessee QSO Party
http://www.tnqp.org/
Elecraft K2/100 #4455
Elecraft K3/100 #366
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