Antenna

A V/U Handheld Moxon Antenna for Satellites

by

The Completed MoxonAs per my last post, I have been getting pretty excited about working satellites. However relying on the little ‘rubber duck’ antenna that came with the IC-T90A hand held does limit the range in a way that I could only really work the satellites at high elevation angles. With costs of commercial V/U antennas for satellite work usually over $200 AUD, it was time to build my own.

I did have some constraints around the antenna design:

  • It had to cost under $50 to make.
  • No speciality materials required – I could either readily purchase from a shop, or I already had materials on hand.
  • It had to be made using tools I had on hand.

The last point ruled out making a crossed yagi antenna to my standards as it would require a drill press to successfully fabricate (I am bad at drilling square!)

In the end a quick google found me looking at making a Moxon designed by LY3LP and modified by M1GEO, but I really wanted to get some close ups of some of the more important parts of the build. What follows is an abbreviated build guide with photos. In all, it took less than 2 hours to construct.

Update 22/12/2018 2.15pm – Yep, this antenna is a winner – here is the audio from the AO-91 pass @ 2018-12-22 1342 AEDT. Big improvement – action starts at around 2mins in.

Read more

Experiments with an End Fed Half Wave Antenna

by
Portable Setup, Mount Direction
Portable on Mount Direction

I went away to the Tasmania’s West Coast in October 2016 and had hoped to work some stations. For radio, the trip was a bit of a disaster with the place we were staying having lots of solar inverter noise. The other thing was that it was very tedious to use a linked dipole in the location I was in. Since that day I had resolved that I would try and end-fed antenna and see how that goes.

The End Fed Half Wave (EFHW) antenna is popular with many QRP Portable stations, particularly for activities such as SOTA or WWFF. The big drawback of the end-fed is the high impedances they have, which means that you need to carry some sort of Antenna tuner to match the impedance with the radio. The thought of lugging around an antenna tuner and then having to retune every time I switched frequency was less than appealing though.

Read more

Building A linked Dipole

by

IMG_1989It’s been a little while since I have posted, and its not because I haven’t been doing anything. I’ve been getting my portable station even more portable that before. Ov er the past 3 weeks where I have had a spare evening I have been putting together a new portable station that is even more lightweight than the previous setup featured in my post on Peter Murrell Reserve. Key to this has been producing a linked dipole.

Linked dipoles provide the benefit of creating a single-wire antenna that is resonant on multiple bands without a tuner by “linking” together lengths of wire with clips. While there is no limit on how many links you make, it may not be practical to make the dipole suit everything between 1.8 and 450 Mhz.

I ended up going for a 5 band antenna – 6m, 10m, 15m, 20m, 40m.

Read more

Letting the Smoke Out I

by

Above is a rather fine example of letting the smoke out. My last post talked about replacing a dipole that had worked well for many years but suddenly not so much. With the options of breaking it all apart to check the inside pieces, or throwing out the antenna, I chose the former. What you are looking … Read more

New HF Antenna for Home – an OCF Windom!

by

OCFWindom

When I made up the 4:1 balun earlier this week, I didn’t realise that I would be putting it to use by the end of the week!

Ever since I got active again, the commercial multi band dipole that I had been using for many years was no longer working optimally. When I first purchased it, it had an SWR of < 1.8:1 across most bands, but recently the SWR had had risen to around 2.5:1 across most bands. After discussing and troubleshooting the issue with the antenna manufacturer, it was decided the cost to replace faulty parts exceeded the original purchase price of the antenna.

It was time to replace the antenna.

Read more

Building A Balun

by

Baluns have always been a bit of a homebrew boogeyman to me, mainly due do what appeared to be some sort of magical winding technique around a toroid. However, given the prices of baluns these days seems to range from $60 AUD upwards, given I have all the parts already at home to make one … Read more

Back on 6m

by

I’m finally back on the 6m band. It wasn’t a cakewalk, with the dipole generally un-cooperative with the element parting ways with the Acro-bat insulator, and then finding the masthead pulley rope (pictured to the right in the photo) was no longer going up to the masthead, meaning that I needed to lower the mast to … Read more