ANTENNAS

Page updated 6th May 2022

40 Meter 4 SQUARE ANTENNA PROJECT. April/May 2022

All antennas up.	Flat across the band.
Base connections complete.	Coax connected up.
All conduit containing coax from antennas to the Box now finished.	Coax and control cables put in conduit first.
Junction box installed to join to shack cabling.	New underground CAT5e control cables pulled through.
5 posts in and removed Hytower antenna.	75 Ohm Coax cut to match 7.140MHz to go from controller to antennas
Radial plates made.	SO239 mounts bent to requirements.
SO239 mounting plates made.	40 Meter 4 Square Antenna Specifications Between posts: 10.5 meters Antenna height: 10.240 meters Radial length: 12 meters Number of radials per antenna: 32 Single antenna ressonance: 7.080 MHz, 1.26:1, 51 Ohm. RG-11 75 Ohm feed cables: Cut for 7.140 MHz -- VSWR readings in shack on 7.100 MHz: NE 1.31, 50 Ohm NW 1.15, 50 Ohm SE 1.24, 56 Ohm SW 1.36, 52 Ohm OMNI 1.76, 31 Ohm

28 MHz 5 element Beam and Tower erection. 14/11/2020

Tower up. 1.5 S points better than my TH6DXX.

Home made antenna - driven element insulators made from plastic.
Design is similar to the Hy-gain 28MHz antenna.

21 MHz Tower erection with the help of Ken VK4QH and Mark VK4FDAD - 28/9/2014

Tower locked in at base with chain from tower then through pulley at the jig point then to bull bar. Guys are attached to the tower and ground. A metal welded 'X' lets the tower sit nicely without rolling. A smooth reverse and the tower is up. Thanks for your help Ken and Mark.

4 Element and 3 Element 21MHz stacked. Jan 2018.

4 Element 6 Meter beam erected - 15/12/2018

EU Beverage antenna installed 17/5/2015

Many thanks to Ken VK4QH and Mark VK4FDAD for their valuable assistance.

Initial results are looking very good. I can now hear stations on 80/40m that were not heard in the noise previously.

Beverage wire held up with star pickets and 50mm water pipe as an insulator. Side fence is 312 degrees which suits nicely.

USA Beverage antenna installed 27/6/2014 facing USA Short path

My new Hy-Gain Hy-Tower installation is now finished

Relay, 80/160 coil fitted, and anti-static coil fitted.

Large coil added for 160m. Note 160m high and low taps at base

Turning my Hytower into a 3 element Vertical Beam. With one relay wired normally closed and the other normally open, flicking the power on will swap directivity. The coils are used to give the element extra length and the relays short the coil out to make a shorter element. Extra elements are placed 1/4 or 1/8th wave from the tower.

HYTOWER HYGAIN VERTICAL INFORMATION
	A	B	C	D	E	F
Number of radials	16	24	36	60	90	120
Length in wavelengths	0.1	0.125	0.15	0.2	0.25	0.4
1.840 MHz	16.30 Mtrs	20.38 Mtrs	24.46 Mtrs	32.61 Mtrs	40.76 Mtrs	65.22 Mtrs
3.600 MHz	8.33 Mtrs	10.42 Mtrs	12.50 Mtrs	16.67 Mtrs	20.83 Mtrs	33.33 Mtrs
7.100 MHz	4.23 Mtrs	5.28 Mtrs	6.34 Mtrs	8.45 Mtrs	10.56 Mtrs	16.90 Mtrs
14.200 MHz	2.11 Mtrs	2.64 Mtrs	3.17 Mtrs	4.23 Mtrs	5.28 Mtrs	8.45 Mtrs
21.150 MHz	1.42 Mtrs	1.77 Mtrs	2.13 Mtrs	2.84 Mtrs	3.55 Mtrs	5.67 Mtrs
28.300 MHz	1.06 Mtrs	1.33 Mtrs	1.59 Mtrs	2.12 Mtrs	2.65 Mtrs	4.24 Mtrs
Spacing in Degrees	22.5	15	10	6	4	3
Total length of wire in Wavelengths	1.6	3	5.4	12	22.5	48
Power gain Db due to increased efficiency	3	3.6	4	4.7	5.2	6
Take-off Angle	30	30	30	30	28	24
Feed-point impedance with 1/4 wave radials	52	46	43	40	37	35
Radial end buried.	YES	YES	YES	NO	NO	NO

6 Pack with coax filters installed. Just add antennas ;-)

My 80/40mtr 1/4 Wave Vertical

Added a 7MHz trap to add the 80mtr band - 21/4/2012

I wound a 7Mhz Trap and attached it to the top of the 1st section (7MHz part). I then added an insulator into the 2" section and used very thin walled aluminium for the top section for resonance on the 80mtr band. The exercise was to allow use of the 80mtr DX window, which my Loop didn't.

1:1 Ugly Balun wound on 4" plastic pipe using RG213.

Ground Mounted Vertical Antenna Notes for 7MHz and below

Correctly configured ground mounted vertical antennas for 7MHz and below will out perform horizontal antennas for DX work.
A horizontally polarized antenna is better for local contacts up to approximately 1000km.
A good ground plane is essential for a vertical to perform well.
A vertical antenna has a lower radiation angle than a horizontal antenna.
A good ground system has a critical angle of about 10 degrees, where a bad ground will give a higher angle of about 30 degrees.
Good ground systems have a low angle of radiation and greater field strength.
Bad ground systems have a higher angle of radiation and up to 4dB poorer field strength than an antenna with an excellent ground system.
Tuned radials (i.e. ¼ wave for example) are the best choice and ½ wave length radials will be an advantage over the ¼ wave.
The more radials the better, although 120 radials seems to be the maximum needed. At least try for 24 to 48 radials if possible.
If you haven’t got the room to lay the radials straight, then bending them around objects or trees is ok.
A horizontally polarized antenna at frequencies above 7MHz maybe equivalent to, but is normally a better performer than a vertical antenna.
A tin roof with about 20-30 degrees sloop makes an excellent ground plane when the vertical antenna is mounted on its peak.

Nissan Navara D22 Diesel - Stopping engine noise on HF

Engine noise on HF is mainly caused by the 70 Volts used to inject diesel in to the motor. Some noise is evident from the under dash fan and also the fuel pump. The Engine noise was so bad I had to wrap the wires in Aluminium foil and earth them to take away 80 % of the noise. I cable tied a piece of bare wire connecting all the foil together and then earthed the cable to the body of the car.