Can we work any dx with a vertical ?

An experience.

by ik3umt

 

This article has been update on September 10th 2009, further links at the end of page.

Introduction

 

My ham activity has always been DX on HF bands.

In 2007 I had to move my shack on QTH were I actually live.

With awareness of urban/environmental trouble of my new QTH (naturalistic territory into protected green area)  also not of my exclusive property, I decided no more to install my old antenna system composed by an Optibeam OB17-4 and a Cushcraft A3WS plus some wire antennas, but  to inaugurate new area with a multiband vertical , aware of performance I would have obtained.

 

 

Which antenna ?

 

The choice of which vertical, was dictated by my own will to not have conventional traps. They work as RF switches , thus leaving that the portion of the antenna in use is physically from feedpoint to trap in use for the determined band.

Also,  as we reduce frequency, further inductance is added by higher frequency traps 

 

 

 

So, the choice  is fell on two candidates, the STEPPIR BigIR and BUTTERNUT HF-9V

First one is a  motorized vertical remotely extendible which allows to work on every band with the best length of radiator and then an almost perfect match.

The second one is a multiband vertical with a particular arrangement of low loss inductors and capacitors which allows the stylus to work on any band for the entirety of its size.

Given the relatively high cost of STEPPIR, and the inevitable presence of certain time waiting for the band changing due to motorized variation of its length, I opted for purchase of a new BUTTERNUT HF-9V having also quality evidence on the same brand antennas already used by me.

My experience here reported can be anyway applied to any model and brand of quarterwave vertical antenna , my intention is surely not to advertise either manufacturers.

 

Installation

 

The installation goal was been to obtain the best made possible antenna system to bring, match or even exceed the performance of my previous antenna system.
     
The first step was to work on a ground plane as efficient as conditions allow.
The efficiency of a vertical antenna is proportional to its ground plane efficiency.
There are countless articles and publications about this,  but truth coming out is always same.
A vertical with a poor ground plane (simple rod planted on  ground, a bunch of radials lying at less worse, 10 squared feet counterpoise) will probably allow you to work many DX in good conditions of propagation and band crowding, but there will be many more stations you will not able to work.
It depends as usual by assessment used: If you tried efficient antennas there'll soon realise, if it is first antenna you ever used , also a piece of wire thrown from the balcony will make you enthusiastic.
Anyway, this is not the matter to approach to a superficial installation.

 

When installing a ground plane antenna, one wonders : “ground mounted or elevated antenna ?”

Here too many theories and pages were consumed.

Often choice is forced (buildings, condominium etc.). In my case the limitation on the bare earth was the existence of a vineyard with a web of tie-rod steel for its guying, surely source of interaction with the radiating element.
The installation was then carried on top of a 10ft tower to bring the whole system beyond anything interfering.

 

 

After some documentation on the issue and some analysis to computer simulation software I decided to install 2 resonant radial for each band, arranged radially opposed (180 °) one another, calculating the length each with the well-known formula Length (ft) = 234 / Frequency (MHz).
The opposite provision of 2 radial for each band allows to obtain a sufficiently omnidirectional radiation lobe.

To achieve radials I used wire from monopolar electrical installations with 1.5 squared millimetres (15AWG) section at which end was installed a plastic tie-clip

 

 

To maintain constant tension of radial I used a counterweight of about 1Kg that using a nylon cord held, knotted to plastic clip and passing through special brackets I built, has taken steps to function.
A chain with appropriate galvanized staples warrant the counterweight clamp in case of nylon wire breaks.

 

 

Two 80mt radials, being rather lengthy, are maintained by a 5 kg counterweight.
This method provides a set of radial free from the pressures of strong wind and aesthetically always in order.

 

    

 

For 6 meters band, 4 self supporting 8mm diameter aluminium pipe radials were installed.
The radial were distributed in 360 ° with the following order to avoid band interactions
80m 15m 30m 12m 6m 40m 17m 20m 10m 6m 80m 15m 30m 12m 6m 40m 17m 20m 10m 6m
Contrary to a ground installation an elevated radials system should not be connected to earth or a metal plate (tower) in his ground common point ,whole system will be detuned otherwise.
Therefore, I have adopted a common ground plate, achieved by insulating polyethylene panel used to support a flat aluminium profile on which radials were locked.
Then,  this ground “ring” has been electrically kept further closer to the feedpoint  to reduce electrical path to radials and more evenly distribute currents.

 

           

 

Ground plane height

 

A particular note about height of ground plane:
I prepared system to facilitate laborious tuning acting on the radials length; contrary to what I originally thought, the exact radial cutting to get resonance is effective only for a system whose height from ground is more than ¼ wave at considered frequency  (the lowest in case of a multiband).
Therefore, on 80mt elevated resonant radials system, is “elevated” only for heights of 65ft or more above ground level .

 

What happens then if radials are not "really" elevated ?
In my case (10ft), ground plane is 1 / 26 wave from ground in 80mt, 1 / 13 wave in 40, 1 / 7 wave in 20mt and so on.
The "surprise" I found during calibration was to not have any variation of resonance frequency  when I went to vary the length of radials, either lengthening or shortening
This is dued to capacitive interaction that occurs between radial and the ground below (which in my case is rather conductive) as well as between radials themselves, this phenomenon detunes further the ground system.

It anyway continues effectively its native function.
The antenna in fact did not submit large calibration deviations from manual specifications.

Once implemented ground plane, I then proceeded assembling as textbook.

 

Some hints

 

Some electrical / mechanical hints :

All joints between pipes and conductive elements generally were treated with zinc oxide paste Penetrox A-13 to maintain the effectiveness conductivity and repellence to oxidation.
As for the HF-2V and HF-6V, the capacitors connection strip can present discharge arc danger, between the extremities of each of two 1-1/8” pipes and the strip itself in presence of moisture and high power.
I then proceeded to isolate the point of attachment with thick thermoretracting sheath.

 

  

 

Locking stubs straps tend, as with other brands and models of American antennas (must be a bad habit design), to slide on pipes even if bolts are tightened to maximum.
I have solved the problem by aluminium rivets, applied of course only on fixed straps (the ones not subject to adjustment for calibration)

 

  

 

Guying

 

Butternut, considering stylus flexibility, does not consider it necessary antenna guying, but I strongly advice it ,having personally seen the amount of force exerted by a strong wind on guyed antenna.
Surely it would be broken at its base unless it had been.

I’ve created for the purpose a polyethylene ring with a 7/8” inner diameter, sliding it on the same diameter pipe so that hang from edge of 1 inch pipe below
The ring has been drilled to allow anchorage of 3 Kevlar guy wires.

.

 

         

 

Tuning :

Tuning is rather laborious because of its 9 bands and many action points, but help of a tool like MFJ259B has made it quite amusing.
Settings of lower bands influence slightly some higher bands.
Tuning was then done,  as textbook, in the following band order:
80m 40m 20m 15m 10m 30m 17m 12m 6m
and retuned again in the same order with fine adjustments for the best result.

The final results of SWR, reported with MFJ 259B connected to antenna feedpoint (including RJ11 75ohm stub) , are as follows:

 

BANDA

 

F LOW

R

X

SWR

 

F MID

R

X

SWR

 

F HIGH

R

X

SWR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

80

 

3,500

120

0

2,2

 

3,522

43

0

1,1

 

3,548

28

17

2

40

 

7,000

35

23

1,9

 

7.093

37

0

1,1

 

7,200

76

20

2,1

30

 

10.100

36

0

1,2

 

10,113

40

0

1,2

 

10,150

58

14

1,3

20

 

14,000

26

0

1,7

 

14,178

29

0

1,5

 

14,350

30

8

1,7

17

 

18,060

112

10

2,5

 

18,120

44

38

2,4

 

18,168

23

25

2,5

15

 

21,000

75

0

1,5

 

21,190

38

0

1,1

 

21,450

27

0

1,7

12

 

24,890

31

0

1,5

 

24,930

31

0

1,5

 

24,990

21

0

1,9

10

 

28,000

87

16

1,8

 

28,715

46

0

1

 

29,500

67

19

2

6

 

50,000

60

2

1,2

 

50,415

43

0

1,1

 

51,00

37

7

1,3

 

 

Where F LOW means the lowest band edge frequency in MHz ,  F MID the minimum SWR point and F HIGH the highest band edge frequency or where SWR is equal to 2.00

The only band suffering more was 17m where hasn’t been possible to obtain an SWR better than 2.4
Anyway I remember you SWR value is NOT index of radiation effectiveness but only of transmission line match.
First contact made on 17m has shown truth, connecting 5N8NDP in Nigeria using 20W for limiting mismatch danger.

 

80mt problem

 

How manual says, 80m band is very narrow (about 50 KHz) and allows the use of first CW portion of 80mt , (my tuning choice in this case)

 

 

What then to do in order to exploit more 80mt portions ?
Idea is rather intuitively: short-circuit some 80m inductor turns bringing in resonance the working frequency, raising it, by mean of relays.

Using 2 relays is possible to add two 50 KHz portions to HF9V, above the resonance frequency chosen as initial.
The same system can work in any similar antenna as well as for any frequency.

Schematic to use is the following one:

 

 

The lack of power leaves original circuit intact, powering to 12Vcc with a certain polarity will active a relay, feeding a reverse polarity will de-active this relay and active the other one causing required turns to be shortened in order to increase resonance frequency.
So, cable used is just a 2-conductor type.
In my particular case I used the RLY2 relay for the CW portion with a 1:2 SWR within 3,550 to 3,6 MHz,  and RLY1 relay for the SSB portion with a 1:2 SWR within the 3,750 to 3,800 MHz.

The circuit has been carried out within a sealed plastic minibox for electronic assembly, directly locked by mean of a polyethylene arm to radiant element near 80m inductor base.

 

 

Inductor tuning straps was made by aluminium and tightened with stainless steel bolts.

 

 

  

 

After appropriate straps tuning, the best SWR results obtained through the operation of each relay were as follows:

 

BANDA

 

F LOW

R

X

SWR

 

F MID

R

X

SWR

 

F HIGH

R

X

SWR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

80 CW2

 

3,533

20

0

2

 

3,562

45

1

1

 

3,590

108

0

2

80 SSB

 

3,720

20

0

2

 

3,768

41

0

1

 

3,813

47

27

2

 

Does it work ???

 

About antenna radiation efficiency, instrumental testing would be very complicated, anyway  first QSOs give a good perspective of functionality.
This is an extract of the first hundred or so QSO from my log, all made with this antenna (with aid in some cases of maximum power here allowed of 500W):

 

 

EK8PL

ARMENIA

31/03/2008

20:56

80m

SSB

59

59

LY1GN

LITHUANIA

31/03/2008

21:38

80m

SSB

59

59

EA6/EA5KA

BALEARIC IS.

31/03/2008

21:24

80m

SSB

59

59

9K2HS

KUWAIT

31/03/2008

23:48

40m

SSB

59

59

5B/LZ2HM

CYPRUS

31/03/2008

23:26

80m

SSB

59

59

OZ/DL1TM

DENMARK

03/04/2008

21:12

80m

SSB

59

59

SP75T

POLAND

03/04/2008

21:20

80m

SSB

59

59

EC7AKV

SPAIN

07/04/2008

20:10

40m

SSB

59

59

W1GUS

U.S.A.

07/04/2008

20:42

20m

SSB

59

59

YK9G

SYRIA

10/04/2008

22:14

80m

CW

599

599

3Z10UM

POLAND

10/04/2008

22:18

80m

CW

599

599

OZ8CTH

DENMARK

10/04/2008

12:46

20m

SSB

59

59

VR10XMT

HONG KONG

10/04/2008

13:44

20m

RTTY

599

599

YK9G

SYRIA

10/04/2008

20:57

30m

CW

599

599

A71BX

QATAR

11/04/2008

11:44

17m

CW

599

599

YK9G

SYRIA

11/04/2008

11:59

15m

CW

599

599

YK9G

SYRIA

11/04/2008

12:50

17m

CW

599

599

3B8MM

MAURITIUS I.

11/04/2008

20:30

40m

CW

599

599

OX3KQ

GREENLAND

11/04/2008

20:51

40m

SSB

59

59

A45XR

OMAN

11/04/2008

20:52

30m

CW

599

599

V63JQ

MICRONESIA

11/04/2008

21:31

30m

CW

599

599

JX9JKA

JAN MAYEN

11/04/2008

21:45

40m

SSB

59

59

HG25STT

HUNGARY

11/04/2008

21:48

80m

CW

599

599

UN12B

KAZAKHISTAN

11/04/2008

21:54

40m

CW

599

599

TI8/DL4MO

COSTA RICA

11/04/2008

22:05

30m

CW

599

599

YK9G

SYRIA

11/04/2008

22:32

40m

CW

599

599

3B8/SP2JMB

MAURITIUS I.

11/04/2008

22:58

80m

CW

599

599

3B8MM

MAURITIUS I.

11/04/2008

23:11

80m

CW

599

599

XU7KOH

KAMPUCHEA (CAMBODIA)

11/04/2008

23:17

40m

CW

599

599

3B8MM

MAURITIUS I.

12/04/2008

12:57

12m

CW

599

599

YK9G

SYRIA

12/04/2008

13:13

15m

CW

599

599

PJ5NA

SINT MAARTEN

12/04/2008

21:15

30m

CW

599

599

CO8LY

CUBA

12/04/2008

21:21

30m

PSK

59

59

VE1DX

CANADA

12/04/2008

22:21

30m

CW

599

599

WP3C

PUERTO RICO

13/04/2008

21:15

30m

RTTY

599

599

ZF1DX

CAYMAN IS.

13/04/2008

22:09

20m

CW

599

599

HK4CZE

COLOMBIA

13/04/2008

22:23

30m

CW

599

599

FJ5DX

SAINT BARTHELEMY

13/04/2008

22:26

20m

RTTY

599

599

ZV5R

BRAZIL

14/04/2008

21:39

40m

CW

599

599

K2SEW

U.S.A.

14/04/2008

21:54

30m

CW

599

599

OX3XR

GREENLAND

14/04/2008

21:58

30m

CW

599

599

WP4O

PUERTO RICO

14/04/2008

22:04

20m

CW

599

599

VC2CQ

CANADA

14/04/2008

22:20

40m

CW

599

599

HZ1IK

SAUDI ARABIA

16/04/2008

21:41

40m

SSB

59

59

JY4NE

JORDAN

16/04/2008

21:43

80m

CW

599

599

9Q1EK

DEMOCRATIC REPUBLIC OF CONGO

16/04/2008

21:58

20m

CW

599

599

VE1AI

CANADA

16/04/2008

22:22

40m

CW

599

599

FM/I2GPT

MARTINIQUE

16/04/2008

22:23

30m

CW

599

599

SV5/SM8C

DODECANESE IS.

16/04/2008

22:37

40m

CW

599

599

YN4SU

NICARAGUA

16/04/2008

22:39

40m

CW

599

599

VP8CMH/MM

FALKLAND IS.

16/04/2008

22:55

40m

CW

599

599

WP3B

PUERTO RICO

16/04/2008

22:59

40m

CW

599

599

RA2FF

KALININGRAD

18/04/2008

20:20

30m

CW

599

599

4S7DXG

SRI LANKA

18/04/2008

20:27

40m

CW

599

599

E74OW

BOSNIA-HERCEGOVINA

18/04/2008

20:28

80m

CW

599

599

SU9NC

EGYPT

18/04/2008

21:38

40m

CW

599

599

9K2HN

KUWAIT

18/04/2008

21:40

80m

CW

599

599

UA2FR

KALININGRAD

18/04/2008

22:07

80m

CW

599

599

ET3JA

ETHIOPIA

18/04/2008

22:21

40m

CW

599

599

EK6LP

ARMENIA

18/04/2008

22:55

40m

CW

599

599

ZP8VAO

PARAGUAY

19/04/2008

20:29

20m

SSB

59

59

4Z60BS

ISRAEL

19/04/2008

20:49

80m

CW

599

599

4X0X

ISRAEL

19/04/2008

20:50

80m

CW

599

599

FJ/DJ2VO

SAINT BARTHELEMY

19/04/2008

21:37

20m

CW

599

599

CO8LY

CUBA

19/04/2008

22:21

30m

CW

599

599

FJ/DJ2VO

SAINT BARTHELEMY

19/04/2008

22:24

30m

CW

599

599

CN8ZG

MOROCCO

20/04/2008

17:30

20m

SSB

59

59

4S7DXG

SRI LANKA

20/04/2008

20:28

80m

CW

599

599

TF3ARI

ICELAND

20/04/2008

21:34

40m

SSB

59

59

5U5U

NIGER

20/04/2008

21:58

40m

SSB

59

59

GB0U

GUERNSEY & DEPENDENCIES

22/04/2008

12:18

30m

RTTY

599

599

MU0FAL

GUERNSEY & DEPENDENCIES

22/04/2008

12:31

20m

CW

599

599

9K2YM/P

KUWAIT

22/04/2008

13:12

20m

RTTY

599

599

VQ9LA

CHAGOS ARCHIPELAGO

22/04/2008

13:16

17m

CW

599

599

KP2YL

AMERICAN VIRGIN IS.

22/04/2008

20:06

17m

SSB

59

59

ET3JA

ETHIOPIA

22/04/2008

20:12

30m

CW

599

599

CE3/VE7SV

CHILE

22/04/2008

21:26

20m

CW

599

599

HK4CZE

COLOMBIA

22/04/2008

21:52

20m

CW

599

579

A45WD

OMAN

22/04/2008

22:39

30m

CW

599

599

VK6HD

AUSTRALIA

22/04/2008

22:51

80m

CW

599

599

A71AN

QATAR

23/04/2008

11:59

15m

CW

599

599

GM3POI

SCOTLAND

23/04/2008

12:34

20m

RTTY

599

599

V51AS

NAMIBIA

23/04/2008

12:42

10m

SSB

57

55

G6PZ

ENGLAND

23/04/2008

20:24

40m

CW

599

599

ZD7X

ST.HELENA I.

23/04/2008

20:28

17m

CW

599

599

9M6/LA6VM

SPRATLY ARCHIPELAGO

23/04/2008

20:30

40m

CW

599

599

YU8AU

REPUBLIC OF SERBIA

24/04/2008

21:10

30m

CW

599

599

EK6TA

ARMENIA

24/04/2008

21:46

40m

SSB

59

59

HC2SL

ECUADOR

25/04/2008

20:12

20m

CW

599

599

ZP6CW

PARAGUAY

25/04/2008

20:56

20m

CW

599

599

ZD7X

ST.HELENA I.

25/04/2008

21:33

30m

CW

599

599

Z29KM

ZIMBABWE

25/04/2008

21:36

40m

CW

599

599

YK1BA

SYRIA

25/04/2008

21:49

40m

SSB

59

59

FJ/DJ2VO

SAINT BARTHELEMY

25/04/2008

21:53

40m

CW

599

599

FS/K9EL

FRENCH SAINT MARTIN

25/04/2008

22:22

20m

CW

599

599

V51AS

NAMIBIA

26/04/2008

13:42

15m

SSB

59

59

KP2/W5IF

AMERICAN VIRGIN IS.

27/04/2008

20:29

20m

RTTY

599

599

JY4NE

JORDAN

27/04/2008

20:30

20m

CW

599

599

OE2008GBK

AUSTRIA

27/04/2008

22:02

80m

CW

599

599

5B/DL2SWW

CYPRUS

03/05/2008

13:24

20m

CW

599

599

EK6LP

ARMENIA

03/05/2008

13:43

20m

CW

599

599

A45WD

OMAN

03/05/2008

21:48

30m

CW

599

599

OL1908D

CZECHO

04/05/2008

20:29

80m

CW

599

599

CO4LS

CUBA

04/05/2008

20:50

20m

RTTY

599

599

HS0ZEE

THAILAND

04/05/2008

21:31

80m

CW

599

599

EA8/DL5MWR

CANARY IS.

04/05/2008

21:44

30m

CW

599

599

FM5CD

MARTINIQUE

04/05/2008

21:50

30m

CW

599

599

N1BAA

U.S.A.

04/05/2008

21:54

40m

CW

599

599

XE3ARV

MEXICO

04/05/2008

21:56

30m

CW

599

599

A45WD

OMAN

04/05/2008

21:59

30m

RTTY

599

599

 

Later, having the chance, number of radial was increased to 4 per band spreaded to 90 degrees each other, with the exception of 80 meters where lack of space did not allow further increase.

 

  

 

Total number of radials is now 34.

With reference to the above concept of capacitive coupling to real ground and the likely between-radials interaction, SWR curves have slightly depart from their initial values.
It has been necessary to enhance it with a light retuning.
With the usual MFJ 259B on hand, the best results were as follows:

 

BANDA

 

F LOW

R

X

SWR

 

F MID

R

X

SWR

 

F HIGH

R

X

SWR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

80

 

3,500

26

0

1,6

 

3,515

40

1

1,2

 

3,540

123

0

2

40

 

7,000

81

0

1,4

 

7,070

45

6

1,1

 

7,200

22

0

2

30

 

10.100

30

0

1,3

 

10,133

32

0

1,3

 

10,150

34

0

1,3

20

 

14,000

47

13

1,3

 

14,166

42

0

1,1

 

14,350

40

0

1,2

17

 

18,060

82

15

1,8

 

18,120

46

21

1,8

 

18,168

34

13

1,8

15

 

21,000

67

0

1,3

 

21,280

39

0

1,1

 

21,450

36

0

1,2

12

 

24,89

34

0

1,2

 

24,990

45

0

1

 

24,990

45

0

1

10

 

28,000

47

3

1

 

28,630

39

5

1,3

 

29,500

121

0

2

6

 

50,000

60

2

1,2

 

50,415

43

0

1,1

 

51,000

37

7

1,3

 

SWR  on 17mt has moved to acceptable values.

 

Lightning in the sky !

As mentioned previously an antenna weakness, as also indicated by the installation manual in troubleshooting section, is the danger of arc discharges between pipes and locking strap supporting 40/80m coils.  
After few weeks, testing an amplifier on 30mt, applying the power of 1.5 kW CW key down this phenomena was presented.
The discharge produced a large burning with carbon residue which provided a further path for RF
Here, therefore, any further high power transmission produced an eye-type effect like arc welder.
This is insulator shoot inspected the following day:

 

      

 

Solution provided by manual is simple cleaning routine and maintenance (!?!?) but to avoid the problem reappears I've radically eliminated the cause.
A polyethylene insulating support has been built to replace the incriminated aluminum strap.

 

  

 

Inner diameter is 1”, and a 5mm diameter stainless steel bolt is inserted, on which capacitors strip and inductors will be locked.
This way, distance between high RF potential points has been greatly spreaded.

 

      

 

Conclusions

 

The final conclusions I have drawn from this experience can be summarizes by these points:

A vertical antenna allows surely to work anywhere on the planet, remembering that propagation will always be the dominant element on a radio contact.

The vertical has as advantages the relative installation simplicity  due to single radiating element, weight and size are usually reduced, also has a low angle of radiation, making it an excellent device for DX, does not need rotor.

As contrast, the vertical antenna have not the peculiarity like yagis to "amplify" the transmitted and received signal toward a particular direction, nor can't attenuate signals from unwanted directions, which could interfere with the signal required or cause, if very strong, receiver intermodulation.
I remember on other hand, that in mathematical terms 6dB gain correspond to doubling voltage that means to quadruple the transmitted (or received) power  then, being the normal S-Meter calibrated to 1 S point increasing every 6dB, feeding a certain power to a vertical (with 0dB gain unit), will produce in the receiver S-Meter a deflection of 1 S point less than the same power fed to a Yagi with 6dB gain.
The difference between the two types of antenna therefore is not so striking as one might think.
The vertical is noisy on reception, especially in low bands, where DX signals are often covered by electrical noise coming from artificial sources of classical human settlements (engines, lamps, controllers, electronic devices -RF and not-, etc.) which have a predominantly vertical polarization.
Then, realization of dedicated antennas for reception on these bands (magnetic loops, flag, pennant, dipoles, etc.) is highly recommended.

Verticals can also lead to a considerable work if installed very elevated with resonant radial, especially if in uncomfortable and very high positions, because of the difficulty to implementing the artificial ground plane.

However I conclude with the statement that, of course, having the chance, the installation of large directional antennas on large towers would be surely preferred but with awareness of the available resources, the vertical antenna together with its installation accuracy is a great tool to be able to compete against more "important" antennas, and break the most avid pile-ups, giving you with pride a lot of satisfaction.

 

 

Upated August, 10 2011 :

 

ST0R DXpedition just finished, these are qsos made with this antenna:

 

 

This country is easy to work from my locator, but pile-ups were huge,

Not bad for a 10ft height antenna in urban environment...!!!

 

 Please , feel free to contact me for any question : ik3umt@ir3ip.net

 

 

UPDATED SEPTEMBER 10th 2009 :

 

Upgrading the ground plane

 

Rebuilding stubs

 

73 de Federico

IK3UMT