The ZL4AI-N4GG array.

 

12 Oct 2019 Version 4, Jan 2018. Version 3.   July 2013 Version 2.  Version 1. Sep 2007.

 

 

 

 

Best kept secret in amateur radio. I cannot not understand why almost every other ham is not using a ZL4AI-N4GG

Read below how to build one, and why you will want to.

 

 

This is a temporary web page until time avails to write this up more formally.

That is provide a fuller description with more systematic information so you can understand size / lengths / details / current patterns etc.

 

 

If you are reading this it is because you have heard me on the air, and you now want to know what is producing that signal.

 

 

First read how the N4GG array below works.

You need to read N4GG's article to understand how the theory behind the ZL4AI-N4GG,

Link below downloads the entire superbly written ARRL QST article by N4GG

http://jking.000webhostapp.com/n4gg_array.pdf

 

 

 

 

The basic layout of ZL4AI-N4GG:

 

 

 

 

 

 

 

It is a dual band N4GG, with a 20 metre and 40 metre elements.

Dimensions can be calculated directly from N4GG article, except the top wire length.

 

Top wire length is (1.28 wavelengths), the extended double zepp on 40. (This is 0.14 meters longer per side).

 

The model shows the centre at about 12 metres, which is where has been since February 2007. My setup in the diagram has slight inverted V layout with ends at 11.5 metres.

 

 

 

 

Diagram below is 20 metres: as you can see ZL4AI-N4GG produces power at 10.2dbi. a big signal.

 

the model shows it i 4 phased verticals.

 

 

 

Below you can see as indicated by the red arrow how at low angles the blue signal of the ZL4AI-N4GG is much stronger than the black dipole. It is the low angle signal that produce the DX.

 

 

 

 

 

BELOW SIDE ELEVATION ON 20 METERS:

 

 

 

 

BELOW SIDE ELEVATION on 20 METERS:

ZL4AI-N4GG in blue Compared to 20-meter dipole, shown in red (below).

6 degrees off horizontal line in pink. Look how much more signal is generated at 6 degrees line by the ZL4AI-N4GG

 

 

 

 

 

 

 

BELOW PLAN VIEW ON 20 METERS:

ZL4AI-N4GG in blue Compared to 20 meter dipole which is shown in red (below)

 

The lobe in the upper right (pink) is pointed directly to Europe.

 

Notice ZL4AI-N4GG, has 4 lobes and beams in 4 directions at once. No need for rotating.

 

 

 

 

 

Below SIDE ELEVATION ON 20 METERS:

Dipole in red,

N4GG in green

ZL4AI-N4GG in blue

6 degrees off horizontal line in pink

The dBi numbers read off the plot show exactly how much more signal is generated at 6 degrees line by the ZL4AI-N4GG

 

 

 

 

CURRENTS on 20 METRES

 

 

 

 

 

PATTERN on 20 METRES SHOWING 11.3 DbI OUTPUT ON LOBES

 

 

 

 

 

 

 

 

 

 

Below ON 40 METRES:

On 40 meters, here below is the output

 

 

 

 

 

 

 

 

 

 

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Some results below:

http://www.dxsummit.fi/Search.aspx

 

 

http://www.dxsummit.fi/images/spotter_icon.e8a055c0.pngSpotter

http://www.dxsummit.fi/images/frequency_icon.b66cf740.pngFreq.

http://www.dxsummit.fi/images/source_icon.3b9707f6.pngDX

http://www.dxsummit.fi/images/time_icon.bf8a03ba.pngTime

http://www.dxsummit.fi/images/info_icon.9a35fbc1.pngInfo

http://www.dxsummit.fi/images/country_icon.6da97538.pngCountry

DH1RK

14185

ZL4AI

22:50 09 Jun 17

New Zealand

SP2XF

14225

ZL4AI

06:55 18 Mar 17

New Zealand

PB5X

14232

ZL4AI

10:18 03 Dec 16

Jeff your dropped off

New Zealand

PB5X

14228

ZL4AI

10:12 03 Dec 16

Tu Jeff for the 5/9+

New Zealand

DK3EE-@

14228

ZL4AI

10:03 03 Dec 16

lp 59+

New Zealand

K0SR

1822.5

ZL4AI

12:05 13 Oct 16

CQ

New Zealand

DK8MZ-@

24945

ZL4AIX

07:17 13 Oct 16

Warren CQing

New Zealand

M3CPY

14190

ZL4AI

09:44 06 Feb 16

59 stroung signal jeff

New Zealand

PD1RK-@

14190

ZL4AI

09:28 06 Feb 16

59 lp tu

New Zealand

PD9Z

14190

ZL4AI

09:16 06 Feb 16

40db cq cq cq

New Zealand

ZL1SLO-@

14250

ZL4AI

07:46 09 Jan 16

tnx hny

New Zealand

CA7CAQ-@

28480

ZL4AI

21:32 25 Apr 15

tnx QSO

New Zealand

PD1RK

14206.900390625

ZL4AI

08:27 18 Apr 15

jeff 59 tu

New Zealand

PB5X

14227

ZL4AI

07:40 18 Apr 15

He is working with 20W tu Jeff

New Zealand

M0HDX-@

14227

ZL4AI

07:27 18 Apr 15

cq dx..no takers

New Zealand

G0LVX-@

14225

ZL4AI

08:56 01 Apr 15

Jeff 5/5 tnx best 73.

New Zealand

OK2MI

14225

ZL4AI

07:19 28 Jan 15

tnx QSO

New Zealand

YU2MBX

14224.7998046875

ZL4AI

07:02 28 Jan 15

cq cq

New Zealand

YU1FE

14225

ZL4AI

07:00 28 Jan 15

tnx Jeff, 73!

New Zealand

JA1PLL-@

14248

ZL4AI

21:00 01 Aug 14

Tnx call see you again 73

New Zealand

JA1BAA

14225

ZL4AI

09:01 26 Apr 14

cq

New Zealand

US7UX

18116

ZL4AI

04:30 05 Apr 14

New Zealand

IZ1UKG

14260

ZL4AIR

21:31 26 Mar 14

TNX QSO

New Zealand

PD1RK

14207

ZL4AI

09:42 31 Jan 14

not qrt new QRG

New Zealand

PD1ATH

14180

ZL4AI

09:37 31 Jan 14

tnx 73 QRT Now

New Zealand

PD1RK

14180

ZL4AI

09:08 31 Jan 14

FB LP

New Zealand

ON3CRD

14203

ZL4AI

07:50 25 Jan 14

booming here 5/9+20

New Zealand

ON7AB

14203

ZL4AI

07:42 25 Jan 14

Tnx friend 73

New Zealand

RU3FN

14203

ZL4AI

07:35 25 Jan 14

tnx QSO Jeff

New Zealand

PY2SBY

14203

ZL4AI

07:28 25 Jan 14

New Zealand

2E0UDX

14210

ZL4AI

10:26 25 Dec 13

Jeff cqn loud

New Zealand

PD5MVH

14205

ZL4AI

10:11 25 Dec 13

Jef 59 Echo M-X-mas LP

New Zealand

PD1RK

14205

ZL4AI

09:58 25 Dec 13

New Zealand

HB9EVJ

14208

ZL4AI

08:34 21 Dec 13

cd dx

New Zealand

ON3CRD

14205

ZL4AI

07:50 21 Dec 13

5/9 HERE JEFF 73

New Zealand

PD1RK

14205

ZL4AI

07:33 21 Dec 13

New Zealand

PD1RK

14198

ZL4AI

10:15 30 Nov 13

New Zealand

RA3YDA-@

14200

ZL4AI

06:39 30 Nov 13

TNX QSO

New Zealand

AG6X-@

14199.7998046875

ZL4AI

05:43 30 Nov 13

New Zealand

A71EM

14199.7998046875

ZL4AI

05:43 30 Nov 13

CQn

New Zealand

F4HDR

14204

ZL4AI

08:50 25 Aug 13

Thank you for QSO

New Zealand

IK4EWM

14204

ZL4AI

08:41 25 Aug 13

New Zealand

KH6BB

14204

ZL4AI

08:28 25 Aug 13

New Zealand

IZ3YGA

14223

ZL4AI

06:05 08 Aug 13

New Zealand

DG1BP

14213

ZL4AI

07:07 06 Aug 13

working G good signal in EU

New Zealand

IK5ZVE

14210

ZL4AI

06:37 13 Jul 13

cq

New Zealand

DJ7ZZ

14206

ZL4AI

05:55 13 Jul 13

nice signal via LP up to 59

New Zealand

ON7AB

14225

ZL4AI

05:58 25 May 13

Tnx Jeff 73

New Zealand

PD1RK

14222.7998046875

ZL4AI

07:13 19 May 13

tu 59 lp

New Zealand

ON7AB

14223

ZL4AI

06:12 19 May 13

Tnx Jeff 73

New Zealand

N0UN

14205

ZL4AI

03:54 18 May 13

CQ

New Zealand

G4BUW-@

14205

ZL4AI

08:44 11 Mar 13

Thanks & 73 Jeff

New Zealand

IS0RXF

14223

ZL4AI

06:13 12 May 12

tnx QSO 5/9 in Sardinia

New Zealand

ON7AB

14223

ZL4AI

05:58 12 May 12

Tnx Jeff 73

New Zealand

M0BSV

14220

ZL4AI

07:26 10 Mar 12

jeff

New Zealand

N3RR

14228.2998046875

ZL4AI

07:57 03 Mar 12

New Zealand

OR4U

14228.2998046875

ZL4AI

07:52 03 Mar 12

CQ CQ

New Zealand

HB9RDE-@

14220

ZL4AI

10:24 02 Mar 12

Jeff 59

New Zealand

PD1RK

14220

ZL4AI

10:10 02 Mar 12

tu very much !!!

New Zealand

G8OFQ

14220

ZL4AI

09:54 02 Mar 12

59 in Hamburg.Tnx Jeff-73s

New Zealand

EA1GGJ

14220

ZL4AI

09:46 02 Mar 12

Jeff cq,cq..tnx

New Zealand

RA0CGY

14215

ZL4AI

07:54 02 Mar 12

tnx QSO

New Zealand

HB9RDE-@

14220

ZL4AI

06:59 01 Mar 12

Jeff 59+05

New Zealand

OE3PRU-@

14220

ZL4AI

06:50 01 Mar 12

Jeff New zealand

New Zealand

S56WYB

14220

ZL4AI

06:34 01 Mar 12

tnx jeef

New Zealand

UR6IST-@

14220

ZL4AI

06:15 01 Mar 12

tnx

New Zealand

RN3BP

14220

ZL4AI

06:13 01 Mar 12

New Zealand

RV6FT

14220

ZL4AI

05:53 01 Mar 12

New Zealand

PP5JN-@

14220

ZL4AI

10:47 29 Feb 12

59+10 IN BRASIL

New Zealand

HB9EVJ

14220

ZL4AI

07:37 19 Feb 12

Tnx Jeff nice QSO

New Zealand

DL3OX

14220

ZL4AI

07:29 19 Feb 12

...tks Jeff,73...

New Zealand

F4FGC-@

14220

ZL4AI

07:17 19 Feb 12

Tnx Jeff for qso 59 by LP

New Zealand

PD1RK

14220

ZL4AI

06:59 19 Feb 12

New Zealand

DL4NAC

14224.900390625

ZL4AI

06:24 17 Dec 11

New Zealand

I5FLN

7148

ZL4AIX

16:48 02 Dec 11

New Zealand

N6OPR

14215

ZL4AI

03:43 16 Jul 11

New Zealand

LU8MB

3795

ZL4AIX

10:40 25 Mar 11

59. direct.

New Zealand

W5SV

7133

ZL4AI

10:32 10 Apr 10

New Zealand

UA0IT-@

14243

ZL4AI

07:34 18 Mar 10

TNX

New Zealand

DK8DX

14205

ZL4AI

07:45 24 Feb 10

Tnx Jeff good DX to EU

New Zealand

PD1RK

14205

ZL4AI

07:38 24 Feb 10

CQ

New Zealand

VK2WAR

7095

ZL4AI

11:07 04 Jan 10

5 x 8

New Zealand

SM3JLA

14182.5

ZL4AI

09:59 28 Oct 09

59 100w/vertical!

New Zealand

I2SVA

7178.5

ZL4AI

05:56 04 Oct 09

test

New Zealand

KB8NTY

14177.2001953125

ZL4AI

04:25 05 Apr 08

jeff

New Zealand

PA0O

7060

ZL4AI

07:19 26 Nov 07

57

New Zealand

LU7YZ-@

14205

ZL4AI

00:44 14 Oct 07

Jeff

New Zealand

W1TO

1812.5

ZL4AI

11:32 04 Jan 07

cq

New Zealand

IK7BPV

7072.5

ZL4AI

05:31 06 Oct 06

CQ

New Zealand

IK7BPV

7072.5

ZL4AI

05:31 06 Oct 06

CQ

New Zealand

F6ARC

7073

ZL4AI

06:36 05 Oct 06

booming

New Zealand

F6ARC

7073

ZL4AI

06:36 05 Oct 06

booming

New Zealand

G0REK

7153

ZL4AI

06:09 24 Sep 06

New Zealand

HB9CVB-@

7100

ZL4AI

06:44 23 Sep 06

Jeff, Dunedin

New Zealand

KB7OUZ-@

14300

ZL4AI

05:09 23 Jun 05

4/5

New Zealand

LX1AX

14284

ZL4AI

23:59 28 May 05

New Zealand

F8DGY

7075

ZL4AIR

05:30 23 Apr 05

ED OC031 TNX FIRST CALL

New Zealand

IZ8DPL

14205

ZL4AI

06:49 12 Feb 05

Jeff

New Zealand

GM0GMN

14187

ZL4AI

09:52 29 Jan 05

New Zealand

2E0SOT-@

14195

ZL4AI

10:24 30 Dec 04

south island zl 5/5 in uk

New Zealand

 

 

 

In Oct 2006, F5VBY paid me the compliment of telling me I had signal of same order as ZL4IR

On 40 metres here are the currents. F5VBY, advised because the currents are high up is the likely reason this works well.

It produces so much gain because currents are high in the air: Like an up side down top feed series of 4 verticals

 

 

 

 

Much more detailed information on a similar arrangement of top fed antenna is provided by W4RNL at the following links

 

http://www.jking.netau.net/bc40ab.html

 

 

http://www.jking.netau.net/bct.html

 

 

 

 

 

 

 

FEEDLINE:

I use 450 ohm ladder line, which results in almost no loss along the feed line, with all the power into the line transmitted.

 

ARRL below shows losses are:

over range 1.8 to 15 MHZ zero dB per 100 feet and

15 MHz to 30 MHz less than 0.14 db per 100 feet.

 

 

What the ladder line and a tuner give is the ability to operate the ZL4AI-N4GG on all bands, without any complexity.

 

 

 

 

Best Feed line Length

I found the best length of feed line was 19.5 meters. Loss for example on 14 MHz is zero dB.

This length gives matches around 50 to 80 ohms for 14 MHz and 7 MHz. It also allows working of 21 MHz and 18 MHz. It will also allows working on higher bands but I do not yet operate there.� To operate on 80 meters you need to use a 4:1 balun at the feed-point.

 

Verification of feed point values:

To do this:

I verified the calculated impedance calculated by the antenna modelling program

4nec2. NEC based antenna modeler and optimizer by Arie Voors

 

http://www.qsl.net/4nec2/

 

Then by using a program similar to Transmission line for Windows to estimate the impedance at the end of the feed line feed point.

I then took measurements of impedance at my feed point using an Autek antenna analyzer and verified that values were these I calculated wire actually measured. Agreement was very good.

 

 

Tuner & Losses

I use a Heathkit SA-2060 tuner to get a match to the transceiver.

 

The tuner typically looses about 7% power. See link below for more detail.

http://www.arrl.org/files/file/Technology/tis/info/pdf/9501046.pdf

 

 

 

 

Compare with Coax loses when there is no Standing Wave Ratio

On 14 MHz with 100 foot of coaxial cable RG213 losses are 0.85 db.

Do the math

dB = 10 log ([Power in] / [Power out])

and you will find for 100 watts in you get 18.0 watts loss and 82 watts out.

 

For comparison, 19.5m length of RG213 the loses are 11.4 watts, namely 100 watts in and you get 88.6 watts out.

 

While the N4GG design achieves about 50 ohm matched line to the coax and eliminates the tuner loss, the losses along the coax are still very high as shown by the following table result in more loss that a tuner and ladder line:

 

 

A typical installation will have 100 to 200 feet of coax,

 

 

Losses

Power in

Total Losses

power out

power out

Length of feed line

 

 

 

100 feet

(30.5 m)

200 feet

(71 m)

No tuner & RG213 coax loss 14 MHz power out

0.85 dB / 100 feet

100 watts

18 watts

82 watts

66 watts

No tuner & RG213 coax loss 28 MHz power out

1.3 dB / 100 feet

100 watts

25.9 watts

74.1 watts

48.1 watts

 

 

 

 

 

 

 

 

 

 

 

 

Tuner loss 7%

7.0 watts

 

 

 

 

Ladder line loss

1.8 MHz to 14 MHz

0.0 over 100 feet

 

 

 

 

Ladder line loss 28 MHz

0.14 dB / 100 feet

= 3.2 watts over 100 feet

 

 

 

 

Tuner & 450 ohm ladder line at

1.8 to 14 MHz

 

100 watts

7 watts

100 -  7.0

= 93 watts

100 - 7.0

= 93 watts

Tuner & 450 ohm ladder line 28 MHz

 

100 watts

-7.0 -(3.2 or 6.4 )

100 -  7.0  - 3.2

= 89.8 watts

100 - 7.0 - 6.4

= 86.6 watts

 

 

 

The ability to get 93% of the power to the antenna is one of the reason for its success.

For 100 watts in you get 93 watts out.

 

 

Below transmission line and tuner losses on 20 METRES:

 

 

 

 

 

 

Below transmission line and tuner losses on 40 METRES:

 

 

 

 

 

 

 

 

 

 

POWER AND SIGNAL RECEIVED

With good band conditions 130 watts PEP has consistently given be 5/9 into Europe over more than 5 years.

If I turn on the Amp at 900 watts, this rises to 5/9 + 20dB. Usually do not need the amp.

 

 

 

 

OPERATES IN 4 DIRECTIONS AT ONCE:  BLUE LOBES IN PLAN VIEW BELOW

I do not have yet rotatable antenna so I cannot compare. But I have had a number of QSOs where the other operator was able to read both long paths and short path, and they could hear me in the UK equally well in either direction. Fantastic advantage is you do not need to turn this around. Just set it up with 1 lobe on Europe / Japan, the opposing lobe ends up on the USA, the other two are in reverse direction around the world to the same receiving directions and all you have to do is operate

 

 

 

 

 

IS A VERY QUIET RECEIVING ANTENNA

Because ZL4AI-N4GG receives only low angle radiation on its main lobes which are on low down angles: It does not receive much high angle radiation, which totally eliminates the high angle incoming signals which are mostly atmospheric noise. As such it only hears the DX on the low angles and hears almost nothing from the high angles. Elimination of high angles incoming radiation eliminates much of the incoming signals with no DX but with much atmospheric noise. In other words it eliminates the noisy high angle signal which have no DX.

[How do I know for sure. Well one of my verticals fell off early on, and then noise level shot up by 2 S points.]

 

 

 

 

 

OPTIMUM HEIGHT ABOVE GROUND

Actually gain is not height sensitive. I ran the 20m computer model with the 5 m verticals at ground level so the top horizontal was 5 m off the ground.

Then I lifted the whole antenna to 10 m height at the top and 5 m high at the bottom. There was very little change in antenna wave shape of the 6 degrees low angle, and hence power out or receiving at 6 degrees remained teh same regardless of height.

As long as you can get a clear line of sight from your antenna at 6 degrees at ground level [i.e no buildings] you could actually mount at ground level. Of course you will need to install a safety fence around the antenna so humans or animals can reach the antenna> best to keep the bottoms of the verticals at least 3 m above ground to install safety separation.�

 

 

 

DISADVANTAGE

I do not hear close in signals. For example over 6 years I have never heard ZL4PW who is 100 kms north of me, but I am told is always on the air.

I hear New Zealand signals from the about 800 to 1,200 kilometres away to the North , but do not hear closer in signals. I hear VK and further afield very well.

 

 

 

 

FUTURE IMPROVEMENTS to yet Undertake

 

 

The ability to receive / transmit omni-directionally:

 

As the ZL4-N4GG works only 4 directions there are 4 gaps of non signal.

 

I haven�t run my models yet but W4RNL work on the similar Bobtail Curtain suggests above 14 MHz the antenna already achieve coverage Omni-directionally.

 

 

 

I need to erect another ZL4AI-N4GG� antenna at 90 degrees or possibly in Triangulated arrangement

See W4RNL advice below:

http://jking.000webhostapp.com/wt.html

 

http://jking.000webhostapp.com/bct.html

 

 

 

 

Hear the power on the air from Italy listening to ZL4AI-N4GG Array fed with 20 watts then 100 watts

http://www.youtube.com/watch?v=3W-yaxabUKM

 

If you would like an NEC file please email me.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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