Tag Archives: Antenna

Science Alive! 2013 Flyer

Science_Alive__2013_flyer_front

Download the flyer and print it off and pass around to friends, family, etc and hope to see you there.

Organisation involved
University of Adelaide
Dept for Manufacturing, Innovation, Trade, Resources & Energy
Flinders University
University of South Australia
Forensic Science SA
BAE Systems Australia
Australasian Radiation Protection Society
The Curiosity Show
Australian Institute of Food Science and Technology (SA)
Coastal Concepts
Engineers Australia
Goyder Institute for Water Research
SA Water
SARDI
The Australian Society for Medical Research
South Australian Neuroscience Institute (SANI)
Australian Science and Mathematics School
Novatech
Royal Australian Chemical Institute
Reef Watch
bugs n slugs
Nature Education Centre
Arid Recovery
Animals Anonymous
Elizabeth Amateur Radio Club
Hackerspace
Giant Games
Vital Veggies
VACANT
Astronomical Society of SA
Voxiebox
Nutrition Society of Aust
Growing More Than Trees Project
Malacological Society of SA
Microscopes and More
The Young Scientists of Australia, Adelaide Chapter
CSIRO Education (Friday)/Double Helix (Sat & Sun)
Science Alive! Showbags (Saturday & Sunday only)
Institute of Backyard Studies
The Fly
Dan Burt the Pianola Man
SciWorld
Australian Dalek Builders Union
Imagine If
Physical Prints (3D printing)
Adelaide Electric Vehicle Association
Plaster Fun House
Adelaide Magic
ZigZag Circus
ANSTO
The Beer Show (Friday Night)
Jesse Deane-Freeman (Friday night)
Deane Hutton’s Magic Show (Friday night)
Rob Morrison’s Jazz Septet (Friday night)
SciWorld Stardomes
Robotics Workshops (Uni Adelaide & Flinders Uni)
YSA Buskers
Solar Panel Tours

Science Alive! 2013

About:
Australia’s largest science expo event with spectacular science, animal and magic shows and a huge range of hands-on fun for all ages. Archaeology and antiquity, Human body and movement, Energy and transport, Environment and nature, Health and medical, Space and astronomy, Innovation and technology

Where:
Goyder Pavilion Adelaide Showground, Goodwood Road, Wayville, SA, 5034

When:
Friday 9th August – 9am-3pm Careers Day for high school students and their teachers
Friday 9th August – 5pm-7pm National Science Week Launch, Goyder Pavilion
Friday 9th August – 7pm-11pm Science Alive! Cabaret, Goyder Pavilion
Saturday 10th & Sunday 11th August – 10am-4pm Science Alive! public event

for more info refer to:
http://www.scienceweek.net.au/science-alive/

As part of a booth organiser for the Amateur Radio & Electronics booth this year we are planning to be more hands on and are going to have a remote station that we’ll have access to in country Victoria we can us to access and transmit on the 40m band via the internet, which we’ll allow the public to make contact with other stations to get a first hand fell to what one aspect of amateur radio is about.

Also hoping to have some IRLP action going to via the VK5RAD 70cm repeater.

Putting up a Dipole Antenna

Putting up a HF dipole is not very hard; all it takes is a little planning, and knowing the length of your dipole. For this I am going to use the OCFD I built as an example, it is 42m long and covers the 80-10m bands.

Firstly you need to find a suitable place to put up your dipole, such as a park or similar. Preferably you’d want to have a heavy-duty squid pole or the like to hold the balun/feed point and coax up in the air; as it is the heaviest point and there’s no point using the ends of the dipole to pull up dead weight, as this will over time cause stretching of the copper wire and you’ll end up with bad SWR. The reason for using squid pole or similar is you can get a rod holder from any fishing store, which you can push into the ground to support the squid pole if its not too windy. Additionally, if there are power lines around you do not want to run your dipole parallel to them, as you’ll pic up more noise off of then.

Once you have selected a place that is adequate for your needs of mounting the ends of the dipole – trees are ideal for this. It is time to put it all up in the air; starting with the squid pole (or similar). Once the balun/feed point coax is up in the air you can deal with the ends of the dipole.

The easiest way I found to deal with the dipole ends is to use a tennis ball and some strong string – such as is used for sewing leather – you drill a hole through the tennis ball, then poke the string through on a bit of wire, and tie the string off around the tennis ball. 10 metres of string should be enough, as you only need it to pull your 4mm diameter rope up into the tree. The reason for using the string and the tennis ball is it minimises the chances of snags and getting it all stuck in the tree – 9 times out 10 if you do get snagged the string will snap hopefully close to the tennis ball and you’ll get both back.

Remember:
Make sure you setup away from power and telephone lines.
It doesn’t matter if there is a little bit of droop in your dipole legs, just as long as where it droops it is 6 metres or more above the ground.

Coax bulkhead

For the last week or so in my spare time I have been working on a coax bulkhead for my window for my coax runs to go too and throw form the window without letting the bad weather and bugs outside.

Hardware used:
* IP65 ABS sealed boxes
* SO259 panel mounts
* RG213 coax (mil spec)
* various nuts and bolts
* length of timber

Cost:
About 30AUD and spare time and cans of drink ;-)

head over to my gallery and check out the images

Homemade Coax Switcher

This is a coax switcher unit I made out of some parts lying around in the junk box. What I have done is modified an old ‘100 Watt CB antenna matcher’ unit and added an extra SO238 and a double pole switch to be some functional I can now use with my 2m/70cm setup.

Parts break down:
Metal box 51x51x32mm from JayCars be ideal, or bigger for more sockets
3 x SO238 panel mount connectors
2mm silver plated copper wire
double pole switch

[PART 4] 3 element 2 meter band Yagi conclusion

Well this is the conclusion after having bit of a play and a fiddle with this 3 element Yagi that I built based on VK5JST build notes. For a 3 element Yagi it is rather directional of about 45 degrees, and very deaf at the back which is a good thing for some setups. Overall it is a rather unusual design with characteristics of much larger Yagi’s for the same band. I have been able to get 1.2/1.3-1 SWR on my Yagi for 146Mhz which I am rather chuffed with and had a good QSO into the VK5RHO repeater from my place. I could probably get better SWR if had a network analyzer to see exactly what the Yagi is doing over 144-148Mhz 2M amateur band.

This Yagi was well worth the time it took to build.

[PART 3] 3 element 2 meter band Yagi construction finished

Well today I made the gamma section for my Yagi and mounted it and also added rubber bits for the ends of the elements and end caps for the boom. I have done a quick test of the Yagi with a 10pF capacitor and the SWR is ~1.5-1. I got a couple air variable capacitors I going to put on the Yagi to better tune it. As it was a lovely day most my work was done outside on the deck. :-)

3 element 2 meter band Yagi construction

This is a 3 element 2 meter band Yagi design by VK5JST that I am giving ago to make. The only difference is I am using 12mm OD round and 19mm OD square aluminum (as it what had around from another project) and I have used 3.2mm dia x 4.5mm long aluminum rivets to hold the elements to the the boom. All I have left to make is the bracket to hold the gamma rod and the bracket for the connector and drilling the holes for the v/u bolt assembly.

The pictures below are where have got thus far.


and yes that is the kitchen table I am working on, ssh don’t tell anyone. hehe

Dual Band (2 Meter & 70 cm) Solid Aluminium J-Pole

This is what I have been up to for the last week or so, building this dual band antenna out of solid aluminum, I have used 10mm solid aluminum rod, and 40mm x 40mm x 3mm angle strut for the base and the driven element connected via SO239 3/8″ stud mount.

I am very happy with the performance of the antenna and the SWR of it. and it was a hell of a lot cheaper than buying one, and more fun :-P

And if you are interested in me making one for you, head on over to my contact page and send me a message