MY HUMBLE ANTENNA EXPERIMENTS:

* LAST UPDATE:

October 2015

For this winter I am starting to experimenting with a 5 elements wire * BRUCE ARRAY * for the 40m Band (with a similar configuration of the previous May 2014 bruce array for 15m band, but with, clearly, quite larger dimensions ;-).
It is a big antenna (110,4 meters of wire) and I use it also for the 80m band, here the diagram with the elements details:

May 2014 :

For the Spring season I made a first test and experiment building a very good 5 elements wire * BRUCE ARRAY * for the 15m band (just a test, to try it, while planning to cut one for the 40 or 80m band in winter). This kind of "Curtain antenna" is interesting because it does not need high elevation (only 0.15wl) from the ground and it is vertical polarization. The horyzontal wires are used to "phase" the 5 verticals elements. I did cut the wires in order to follow Mr. Cebik's suggestions (W4RNL) and the Bruce Array presents some very good resonances also on 20m band ( swr 1:1 on 14m and 1:2 on 15m ). As I do use the antenna mainly on 20m , I elevated it from the ground at about 5m (0.25wl on 20m) so the gain should be at least 5dB with an elevation angle of about 16 degrees on 20m and about the same on 15m band. With the antenna in place, the Antenna Analyzer measures at feedpoint (using the 1/2 wl coax trick) is: Z=245 O / X=5O / L=50nH @ 21.3 MHz.
I provisionally use an homemade 4:1 balun to get an unbalanced feed, then I placed a small 1/4wl 75O coax and finally 6wl of rg213 to the station.
I got good results for Dx on 15 & 20m.

March 2014 (80m - 1/4 wl. "VERTICALS" wire antennas ARRAY) :

I tested a stack of two 1/4 Wave monoband Vertical wire antennas for the 80 meter band (19.8m, about 65ft long) with elevated counterpoise in a similar phase configuration as for the previous phased delta loops (pls see previous antenna's configuration below) .

Each antennas has Fifteen (19.8m long 1/4 wl) Elevated Radials: 1m to 2m from the ground. Some of the elevated radials are now 1/2wl long.

My property is at an altitude of 830m slm in the mountains; I live in a 30° slope terrain: uphill is north, downhill is south.

The two wire verticals are 1/4 wl (90° distant): one vertical antenna is north (uphill) of my property and the other is south (downhill). The antenna are in-line from south to north.

I use the same relay's box I used with the previous Delta loop experiment (see following pdf).

The feed lines are both identical: 270° (3/4 wl, an odd multiple of 1/4wl) of 75 Ohm coax in order to use the "current forcing" method.

I am experimenting only "empirically" with the phasing / delay line's lenght in order to get the best (hopefully 15 or 20 dB) front to back ratio that at the present is only 5 to 10 dB.

I transmit mainly "broadside" (max gain) and I listen Dx with the antenna's system facing south or north depending on the QRM direction I want to cut....

View from North (uphill):

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View from South (downhill):

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Please refer to -Previous- 2010 phasing delta configuration for my phasing relay box information :

February 2010 : "PHASED DELTA LOOPS"

please click here: www.iz5ljb.eu/_sgg/phased-inverted-delta.pdf

Previous experiment, December 2009:

 - Experimental HALF SQUARE ANTENNA for the 80m :

This antenna is composed by:  2 Verticals elements of 20,5m = 67,2' (λ/4) fed in phase by a 36.2 m = 119' (lambda/2) Horizontal top wire.  A kind of inverted U.

My Half square antenna is current fed at one of the top corners (low impedance, current feeding) this method gives 50 Ohms at 3.750 MHz (swr: 1,2 : 1)

The Horizontal top wire is at an “average” height of only about 50' = 15m (sloping ground at my QTH).

The vertical sections are elevated from the ground at a height of about 2,5m = 8’

I decided to add a radial system: actually an “elevated counterpoise” radials system, composed of 5  (λ/4) radials at the verticals’ bases and one long (λ/2) radial uniting all the 2 verticals’ radials, parallel to the top horizontal wire. All the radials are elevated and insulated from the ground at an height of about 1,7m = 5.6’

This cheap and experimental wire antenna outperform the 2el. wire yagi especially in Dx !

November 2009:

2 Phased Halfsquares antennas:

I replaced a dipole with a second half square antenna distant 1/4 lambda from the first half square.

The western antenna coaxial cable has an electrical lenght of 1/2 lambda on 80m, the second (east) antenna's coax is 1/4 lambda.

Both coax are together in a PL259 T-splitter. In this way I made a very simple and cheap Phasing sistem.

As the antenna's distance is half lambda, the westner antenna gets the signal from the Americas 90 degree before the eastern halfsquare. If you place a feeding line that is 1/4 lambda longer on the westner antenna you should get the 2 antenna working in phase... isn'it ? :-) ....

7th of September 2009 :

NEW BEVERAGE ANTENNA

I recently built my first Classical single direction BEVERAGE ANTENNA.

It is 4 lambda on 80m (total length = 308m = 1008' only). Beaming South.

It is supported by local trees using insulators. Classical 9:1 transformer and 456 Ohm terminal resistor and two 1.5meters ground rods.

The Beverage average height from the ground is about 4m. I also made the sloping section of about 1/4 lambda at the resistor end to get a lower angle for Dx.

The feeding lenght is 80meters of RG6/64 - 75 Ohm coax cable, not buried, it is only laid on the ground at the moment.

The coax is tuned: without antenna it resonates with SWR 1:1 at 3.730 MHz...even if the velocity factor was 0.82.

I calculated and cut the coax, (considering the velocity factor) at an electrical length of 1λ + λ/4  =5/4 λ

(NOT IN USE ANYMORE):

July - 2009:

I took out all the others antennas and I am experimenting with an homemade Full size Horizzontal 3 elements (director of 37m, driven element of 37,4m and reflector of 39m) WIRE YAGI for the 80m band (used also for 20m and 40m band) - (only 16 to 20 meters from the ground) with 1:1 balun home made on ferrite rods, tuned by Mfj 962C manual tuner to also 20m and 40m !

The SWR (clearly without the tuner, straight from the antenna) is less than 2:1 from 3.620 to 3.800 Mhz

The elements spacing is 11.8m (in practice 12 meters "average" :-)

The antenna wire section is 1,5mm plus coating.

My full size 80m - 3 elements wire Yagi for the 80m voice band:

The antenna is working very well for National and European QSOs where I get a standard 5/9+10 dB but I am not able to test it properly on DX because of the very bad propagation during summer in 80m. Anyway I noticed that the antenna is quite noisy: in 80m the noise level is always 9 +20 dB average ! Probably this antenna picks up everything... ?

I am considering taking out the homemade balun and also the coax KSR240 (chinese replacement of LMR240) and replacing the complete feedline with a ladder line to check if the noise will diminish.

In 40m the noise is lower: intensity 6 or 7dB average

The previous experiment, a 2 elements wire yagi full size for the 80m was less noisy and it was working pretty well also in DX. I will have to test the new 3 elements yagi in autumn and winter... I will let you know ! :-)

I have to thanks Vlad RW1AC (Vladimir Askenov ) from the RU1A cheif club station for his advice about the measures of the wires, he checked them with the software and gave me wise advices.

I also took some inspiration :-) from Stephen VE6WZ website http://www.qsl.net/ve6wz/intro.htm
and from the ARRL antenna handbook..but my level is just a "game" level. Look at their web site for serious information.

3 elements wire Yagi for the 80m measures :

My aim was to make the antenna resonating mainly on the 80m Dx window (3.795 to 3.8MHz), anyway it has a low SWR on all the 80m voice operation band. The lower SWR point is 1,3:1 @ 3.8 MHz.:

The antenna works without tuner in all the 80m band for voice operation but it is quite noisy (?) compared to my old experiment, the yagi with 2 elements. The SWR responce is also quite strange (2 peaks?).

So I am replacing the ferrite rod 1:1 balun with the famous "Ugly Balun", at the moment I am now trying to find out why the Choke Balun SWR responce is a lot worst than before: (bad SWR 3:1 in all 80m band!!)

New Choke Balun (Ugly Balun) - the choke is 6 meters (19feet) of coax LMR240 (about 13 turns on an open plastic drum)

- 80m Monoband Horizzontal Full size 2 elements (37 and 39m = 121' and 127' ) wire YAGI

The Yagi is only 18 meters = 59' from the ground. It is tuned with SWR 1:1 @ 3.750 MHz. The 2 Elements distance is 12m = 39' (0.15 lambda).

The active (dipole) element is fed by a 1:1 balun home made, the Beam can be tuned by Mfj 962C tuner also to 20m and 40m bands

YAGI, end of August 2009:

The choke balun was not working at all to improve SWR response! Is it a legend ?

Actually SWR is too high with the ugly and useless choke. The simple Balun 1:1 is a better solution.

Anyway, the 3 elements are too difficult to handle and to tune for a wire antenna simply hanged between trees.

I decided finally REMOVED ! the DIRECTOR and the Yagi gain improved and the SWR got : 1:1 @ 3.7 MHz !

* * *

80M - 3 ELEMENTS WIRE YAGI EXPERIMENT RESULTS AND PERSONAL EXPERIENCE :

I believe that using 3 elements, even at a low height, is a VERY tricky business, the gain and the swr are worst than in the simple 2el. yagi if the 3 elements distance cannot be regulated properly.

An imperfect parallelism of the wire elements and the impossibility to find a precise length can result in improper SWR values and low gain, even if modelling software was used: in reality thing are trickier than virtually...

A 2 elements wire yagi is the best solution, the gain is far better that a single dipole.

So I am now using again a 2 elements wire yagi for the 80m band, but the take off angle is clearly too low for DX with just 15m elements height..

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FULL SIZE 2 ELEMENTS WIRE YAGI FOR THE 80M :

(director 37.60m. / reflector38m / distance of the elements 7m to 8m)

I recently converted my home made Half Wave Wire DIPOLE for 80m band (20 meters from the ground) with homebrew 1:1 balun,

to a Full size 2 elements wire yagi for the 80m. I used the ARRL hand book formulas and many internet sources.

The director dipole arms are 18.8 meters each (61.67 feet each),

the wire section is 1.5mm (0.06 inches section, about AWG15) + plastic shield.

The director dipole was perfectly tuned on 3.780 MHz, SWR 1:1, for voice operations.

The Director is only 20m (about 65 feet) from the ground, hanged to 2 trees.

It is horizontal, parallel to the sloping ground and, naturally, the dipole is also sloping but mainly parallel to the "terrace" sloping ground.

The ground is mostly wet, I am in a mountain area (Apennines mountains Range 850m slm).

The dipole direction is east / west.

I decided to add a Reflector element to the dipole to build a Full size 2 elements wire yagi for the 80m ;-).

The reflector is 38 meters long (124,7 feet) and the reflector wire section is 1.5mm (0.06 inches section = AWG15) + plastic shield.

The ARRL radioamateur handbook gives the formula: 0.15 x lambda to calculate the reflector distance form the director, just to give a 'fair' compromise.

The reflector wire is "about" 8 meters from the director ( +/- 1m :-). Both the Yagi wire elements are hanged to trees.

I am not able to make full analysis of this antenna but I will be really happy if some experienced OMs will give me any advice or make some test with me.

Anyway, adding the reflector, the antenna have a lower radiation angle and "some" more gain compared to the previous dipole.

I am receiving good reports and I am now able to receive more Dx stations. The front to back ratio could be bad mainly due to the antenna low elevation (only 20m).

I will be happy to write some more about the home made 2 el. Yagi performance when I will have tested it some more.

I will also try to take some pictures of it.

I probably will try soon to add an additional element to build a 3 elements full size yagi for the 80m band....

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Half Wave Wire DIPOLE for 160m band (20 meters from the ground)

(77.2m. x 2 arms)

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* Home made “Hentenna” for VHF and another small Hentenna for UHF:

* I also modified 2 TVI antennas for UHF & VHF for my small multiband receiver Icom Ic-R5:

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·  DISCONE antenna (I use it for VHF) on the roof.

·  9 elements YAGI for UHF, home made, placed on the roof.

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* LONG WIRE for 160m / 80m / 40m etc. - 54meters long (only 20 meters from the ground):

* DOUBLE DIPOLE home made for 40m and 80m bands (20 meters from the ground) with 1:1 balun home made, tuned by Mfj manual tuner:

* WIRE DIPOLE home made FOR THE 20M BAND (20 meters from the ground) with home made 4:1 balun.

·  Full lambda "DELTA LOOP" - 160m long (useful on 160,80,40 & 20 meters), home made with 155 meters of Ø1.5mm² coated electrical wire, hanging to some trees, only 10m from the ground, apex feed with small homemade balun, only 30° slope. It works well on 20 meters, omnidirectional.

·  5 Elements wire monoband YAGI for 20m band, home-made, hanging to some trees, beaming to East/South-East; (10 meters from the ground):

·  Coax Dipole for the 20m band (10 meters from the ground).

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