Tag Archives: Amateur Radio

[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. :-)

Adelaide Science Alive 2011

Science Alive! is Australia’s largest community science expo with over 50 interactive science booths, spectacular chemistry science shows, native animal shows, magic shows, robots, circus workshops, sports science activities, giant Star domes, electric vehicles, bugs n slugs, gene technology and dozens of different hands-on activities to engage all ages.

What: Science Alive – 2011
Where: Goyder Pavillion, Wayville Showgrounds
When: Friday 5th – Sunday 7th August

‘Radio and Electronics’ booth at the Science Alive 2011
For more information please refer to the Amateur Radio at Science Alive 2011 wiki page by Paul.

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

Amateur Radio VK callsign lookup

With a friends (thx darkrose) help last night you’ll have noticed that there is a ‘VK callsign lookup‘ search bar widget to the right. All it does is to make looking up callsigns from the ACMA websign little faster and lot less confusing. Anyways here is a copy of the code if you like to add it to your site.

HTML version:
With the HTML version you can type in the url bar for example search.html?callsign

<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
<!--
function popupform(myform, windowname)
{
if (! window.focus)return true;
window.open('', windowname, 'height=480,width=800,toolbar=no,statusbar=no,scrollbars=yes');
myform.target=windowname;
return true;
}
//-->
</script>
</head>
<body>
<form action="http://web.acma.gov.au/pls/radcom/register_search.search_dispatcher" onSubmit="popupform(this, 'join')" method="POST">
	<input type="hidden" name="pSEARCH_TYPE" value="Licences" />
	<input type="text" name="pQRY" id="pQRY" />
	<input type="submit" value="Search" />
</form>
<script type="application/x-javascript">
window.onload = function() {
	var l = window.location.toString();
	var v = l.indexOf('?');
	if (v < 0)
		return;
	l = l.substr(v+1);
	if (l && l.length) {
		var v = document.getElementById('pQRY');
		v.value = l;
		v.parentNode.submit();
	}
}
</script>
</form>
</body>
</html>

WordPress version:

<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
<!--
function popupform(myform, windowname)
{
if (! window.focus)return true;
window.open('', windowname, 'height=480,width=800,toolbar=no,statusbar=no,scrollbars=yes');
myform.target=windowname;
return true;
}
//-->
</script>
</head>
<body>
<form action="http://web.acma.gov.au/pls/radcom/register_search.search_dispatcher" onSubmit="popupform(this, 'join')" method="get">
        <input type="hidden" name="pSEARCH_TYPE" value="Licences" />
        <input type="text" name="pQRY" id="pQRY" />
	<input type="submit" value="Search" />
</form>
</body>
</html>