Half Wave Dipole Calculator

Here is the link to Dipole Calculator

HF Antennas impedance matching.

HF Antennas impedance matching.

Antenna BALUNs and UNIONs

Generally a balun consists of two wires (primary and secondary) and a toroid core: it converts the electrical energy of the primary wire into a magnetic field. Depending on how the secondary wire is done, the magnetic field is converted back to an electric field..

Balun

A Balun is a device that joins a balanced line (one that has two conductors, with equal currents in opposite directions, such as a twisted pair cable) to an unbalanced line (one that has just one conductor and a ground, such as a coaxial cable). A balun is a type of transformer: it's used to convert an unbalanced signal to a balanced one or vice versa. Baluns isolate a transmission line and provide a balanced output.

In a Balun, one pair of terminals is balanced, that is, the currents are equal in magnitude and opposite in phase. The other pair of terminals is unbalanced; one side is connected to electrical ground and the other carries the signal.

The Baluns (transformer tipe) also translate impediment  differences. (450Ohm to 50m )

Some impedance matching guide lined.

1. A (1 to 1) BALUN is mostly used with center taped Dipoles. (50 Ohm Antenna to 50 Ohm Coaxial cable)
2. A (2 to 1) BALUN is mostly used with HF quads and loop Antennas (100 Ohm Antenna to 50 Ohm Coaxial cable)
3. A (4 to 1) BALUN is mostly used with Off center dipoles, Windom and Sky wire loops 80m and 160m band  (200 Ohm Antenna to 50 Ohm Coaxial cable)
4. A (6 to 1) BALUN is mostly used with Off center dipoles that is installed higher than about 25m. (300 Ohm Antenna to 50 Ohm Coaxial cable) you could also use 300 ohm robin cable and the mach it to 50 ohm.
5. A (9  to 1) BALUN is mostly used with end fed long wire antennas.  (450 Ohm Antenna to 50 Ohm Coaxial cable) you could also use 450 ohm ladder line and the mach it to 50 ohm.

50 Ohm coaxial cable vs 450 Ohm or 600 Ohm ladder or window line?

Coaxial cable 50,75 or 92Ohm

Ladder feed line

The primary advantages of coax with respect to ladder line are

1. Most transceivers are equipped with 50 ohm coax connectors, whereas using ladder line requires a Balun or balanced tuner
2. Coax cable is not affected by nearby metal objects, unlike ladder line
3. The impedance of coax doesn't change when it rains or snows, unlike ladder line

The primary advantages of ladder line with respect to coax are

1. Lower loss at frequencies of 28 MHz and up words
2. Easier to make connections
3. Can drive a balanced antenna (e.g. a dipole) without a Balun

Why not put your own Satellite in space ?

 for as little as $19.00

1. Transmitter power is 10mW DSSS transmitted through a dipole. The maximum solar panel power available on the standard device is 100mW. 
2. Hardware Development Scouts can potentially have as much as 500mW solar power.
3. The orientation of the device in orbit around the earth should be able to be determined most accurately by use of the magnetometer.
4.  It might also be possible to work out orientation by using the single pixel sensor as a moon/earth/sun sensor.
5. They will be doing there best to make the landing site the earth side of the moon.
6. If you are, or would like to be, a radio amateur, they will show you how to communicate directly with your spacecraft in space when it is nearby using inexpensive UHF and S-band equipment. Communication at (cis-)lunar distances is more expensive (typically requiring 5-24m+ steerable dishes), but available to some clubs and enthusiasts.

More info is available at http://www.kickstarter.com/projects/1677943140/send-your-own-pocket-spacecraft-on-a-mission-to-th

My WebSDR on 2M Satellite and ISS frequency

I have disabled the 2M SDR until I can fix the adjacent channel interference.
I am only running the 40m SDR for now.

My WebSDR on 2M Satellite and ISS frequency seems to be stable with some adjacent channel interference.
I will try and make some change with a different antenna to reduce the interference.(Eggbeater antenna)
Here is the link http://zr6aic.giga.co.za:8901/
Here is also a very nice link to find out what is herd from a satellite point of view (live Sat DX spot)
 http://www.dxsummit.fi/CustomFilter.aspx?customCount=50&customRange=507

Beacons http://users.iafrica.com/z/zs/zs5s/bulls/BCNQRT.TXT

Botswana DX expedition

I am planning to go to Botswana from 25 April to 2 Mei and planning to do some DX from there.
I will try and operate on the following frequencies and times.(FT857D) (call sign A25-ZR6AIC)

1. During the day I will be mobile with vertical on 20m.(On my Hilux)
   
2. At night at 20:00 (SA time GMT + 2) I will be operating on PSK and PSKmail 10.148Mhz (Dipole). I will try and send APRS details via PSKmail so you could see my position.
3. At about 20:30 I will be listening on 40m 7.07Mhz (Dipole)
4. If PSKmail works you will be able to mail me in Botswana on zr6aic[AT]gmail.com

If I have Internet I will update this post.
http://www.blogger.com/blogger.g?blogID=682099895127146822#editor/target=post;postID=1489050289151511270
(Just waiting for final Approval from Botswana)
Got Approval from Botswana and everything is good, tested my 20M dipole last night and made some small adjustments. 
All went well and I did some contacts in the evening on 20M but had a problem with my audio cable and could not do any digital modes (psk, PSKmail).

MiniVNA Pro Antenna Analyzer

Just got my MiniVNA Pro Antenna analyse and started analyzing my HF multi trap inverted V antenna and it did not look good. I will have to re-tune almost all the bands.

1) What's nice about the analyzer you can see all the band details in one sweep and the re-tune and compere  the graphs.
2) Took me a wile to find out that resonant point is not necessary the lowest return los measurement but rather 0 phase difference between Tx and Rx signal when analyzer is connected directly on antenna.  Its very easy to do with the blue tooth connection to MiniVNA hanging off antenna.
    HI...

How to install the software on Linux

The VNA/J software will work on Windows, Linux and MAC as well. The compatibility was possible using the JRE 6 + (Java runtime from SUN microsystem) http://www.java.com

1) Check the java version installed on your linux

java -version

java version "1.7.0_05"

Java(TM) SE Runtime Environment (build 1.7.0_05-b05)

Java HotSpot(TM) Client VM (build 23.1-b03, mixed mode)

Apparently the link is broken here is a link to the jar http://download.dl2sba.com/vnaj/3.1.7/vnaJ.3.1.7.J1_6.jar

2) If you don't have java install it. The SUN/ ORACLE version is better.

3) Download the miniVNApro software from http://miniradiosolutions.com/swfw-updates

4) Change the permission on the file that you downloaded to have execution writes (vnaJ.2.8.3c.jar)

5) Run the command  java - jar vnaJ.2.8.3c.jar  in the file directory of the vnaJ.2.8.3c.jar

You could also create a short-cut with full path to java as well as to vnaJ.2.8.3c.jar file and execute it that way.

6)There is two ways to connect to the VNA  device (via USB cable or via Bluetooth)

6.1) I will first explain how to connect the VNA to USB port.

On UBUNTU possibly the same on all Linux versions you need to find out what is the USB serial port of  the VNA device. This can be done by disconnecting you VNA fro usb and the running the following command in Terminal tail -f /var/log/messages and the connect your VNA to USB on PC.

You should see something like this.

Jul 14 14:05:41 chackpc kernel: [917066.397530] usb 2-2.3: new full speed USB device using uhci_hcd and address 15
Jul 14 14:05:41 chackpc kernel: [917066.552690] ftdi_sio 2-2.3:1.0: FTDI USB Serial Device converter detected
Jul 14 14:05:41 chackpc kernel: [917066.552817] usb 2-2.3: Detected FT232RL
Jul 14 14:05:41 chackpc kernel: [917066.552826] usb 2-2.3: Number of endpoints 2
Jul 14 14:05:41 chackpc kernel: [917066.552834] usb 2-2.3: Endpoint 1 MaxPacketSize 64
Jul 14 14:05:41 chackpc kernel: [917066.552840] usb 2-2.3: Endpoint 2 MaxPacketSize 64
Jul 14 14:05:41 chackpc kernel: [917066.552847] usb 2-2.3: Setting MaxPacketSize 64
Jul 14 14:05:41 chackpc kernel: [917066.554902] usb 2-2.3: FTDI USB Serial Device converter now attached to ttyUSB1

The serial port as in RED above will be the port to configure in your VNA/J apllication under the analyzer setting menu see details in Picture.

Select the test button after you have selected the Analyser model and port.

Should see something changing to green at the bottom indicating the driver and port works.

Select update. (Mite get warning that there is now calibration data the first time you us the program)

Follow the operting instruction to calibrate and normal use of VNA device.

6.2) I will now explain how to connect the VNA via Bluetooth  (Very handy if you want to test the antenna without co-axle cable and connecting it directly to antenna)

Make shore the VNA is disconnected from USB and the on switch is switched on, there should be a blue led flashing at the bottom of device.

6.2.1) Then install Blueman applet ( synaptic package manager or commad line  sudo apt-get install blueman)

Then select in ubuntu menu System > preferences > Bluetooth Manager

Search for VNA device if not already in found device's.

Write click on found device and pair with device using password 1234

Then write click on PRO sn 01150 and click on setup...

Then select connect to serial port

you will the see a popup something like serial connected to /dev/rfcomm

Start the application vnaj as in section 5 above.

Select analyzer menu and the setup as in section 6.1 above.

The problem you have now is the /dev/rfcomm is not in the list of serial devices.

The reason for the problem is it seems that the VNAJ program only display devices with tty at the front

To resolve the problem run the following commands.

ls /dev

you should see something like this

agpgart          fd       loop4               psaux  ram6     sdc       tty11  tty25  tty39  tty52  tty9        vcs    vcsa7

autofs           full     loop5               ptmx   ram7     serial    tty12  tty26  tty4   tty53  ttyrfcomm0  vcs1   vga_arbiter

block            fuse     loop6               pts    ram8     sg0       tty13  tty27  tty40  tty54  ttyS0       vcs2   zero

bsg              hidraw0  loop7               ram0   ram9     sg1       tty14  tty28  tty41  tty55  ttyS1       vcs3

btrfs-control    hidraw1  mapper              ram1   random   sg2       tty15  tty29  tty42  tty56  ttyS2       vcs4

bus              hidraw2  mcelog              ram10  rfcomm1  shm       tty16  tty3   tty43  tty57  ttyS3       vcs5

char             hidraw3  mem                 ram11  rfkill   snapshot  tty17  tty30  tty44  tty58  ttyUSB0     vcs6

console          hpet     net                 ram12  root     snd       tty18  tty31  tty45  tty59  uinput      vcs7

core             input    network_latency     ram13  rtc      stderr    tty19  tty32  tty46  tty6   urandom     vcsa

cpu              kmsg     network_throughput  ram14  rtc0     stdin     tty2   tty33  tty47  tty60  usbmon0     vcsa1

cpu_dma_latency  log      null                ram15  sda      stdout    tty20  tty34  tty48  tty61  usbmon1     vcsa2

disk             loop0    oldmem              ram2   sda1     tty       tty21  tty35  tty49  tty62  usbmon2     vcsa3

dri              loop1    pktcdvd             ram3   sda2     tty0      tty22  tty36  tty5   tty63  usbmon3     vcsa4

ecryptfs         loop2    port                ram4   sda5     tty1      tty23  tty37  tty50  tty7   usbmon4     vcsa5

fb0              loop3    ppp                 ram5   sdb      tty10     tty24  tty38  tty51  tty8   usbmon5     vcsa6

you should see something like rfcomm0 or rfcomm1 ....

the run the following command

 ln -s rfcomm1 ttyrfcomm1 

Then restart your vnaj program and you now will see a serial device in you setup list ttyrfcomm1 

test and and update should work now.

Enjoy your VNA ....

My Antennas

Here is a scanned image on my Wideband antenna including coax cable done on Ubuntu.
(Antenna COMET DS-150S)

SWR and phase

My Multi trap Dipole
(CWA-1000 HF 5-BAND TRAP DIPOLE)

SWR and Phase

My (COMET CHV-5X 5 BAND DIPOLE)

Very narrow band's (The multi trap dipole is 10 times better than this CHV-5X)

SWR AND Phase

30m 1/2 wave Dipole

I now have add two active loops for the 20m and 80m SDR receivers.

here is the details

and here is the connection diagram

Here is some of my antennas.

2m Eggbeater, 2m,70cm jpole, 3element 2m/70cm yagi on rotater,
70cm Eggbeater, Discone, 2m,70cm 5/8vertical, Multiband HF  V Dipole.

Same Antennas seen from the Bottom

2.4 Ghz TX to Satellite

10Ghz RX and 2.4Ghz TX antennas

10Ghz LNB

Vertical Polymerization for Narrow Band 10Ghz

10Ghz RX

Setting Up My Dish 60 Elevation and 4 Deg Azim

Build inverted V for 10.184 Mhz

I have build a proper inverted V Dipole Antenna for PSKmail and it made a big difference compared to my multi trap dipole.