Back in about 2012 I made myself a Multi-band dipole antenna, based a design by [[VK3ZPF|http://vk3zpf.com/link-dipole]] That I saw in action on our French Island National Park (For KRMNPA) activation in January 2009, using RCA plugs. After getting it up and having trouble with the FT-817 not working, it went into a box, unused for a few years.

In 2015 with the antenna up and looking at it, and trying to work out it’s resonant frequencies mathematically, I finally worked out what was wrong. The elements were backwards! The first official outing after being fixed was up [[Mt Hickey|VK3/VN-015 Mt Hickey]], where I only actually ended up using 40m, but I did a quick test of the SWR, all seems pretty good!

I now have the antenna set up at my new QTH, and I have had a chance to test out the [[toroid balun|Toroid Balun]] I had made, the balun is currently not attached. After several tests, this is where I am at with Bands & SWR:

|! Band |! Element Length |! SWR |! Notes | |40m |4820 |Varies |Closest element to the ground, SWR is likely to be unstable, analysis of total length shows that this element is short by about 400mm | |20m |2520 |Getting close to high (about 2:1?) |Analysis shows element is about 200mm short | |10m |1100 |Minimum about 28.5MHz |Works well for local, haven’t heard any DX | |6m |1470 |Minimum around low end of 6m, appears to be wideband |Wideband on this band, get some interesting effects from transmitter complaining of high SWR with no transmitted power, this might be that no balun is installed |

//Note:// 40m Antenna works on 6m as well, but haven’t quantified the performance difference yet.

!!Future

I will be doing a complete redesign based on a [[VK3YY|https://vk3yy.wordpress.com/2013/12/22/multiband-linked-dipole-using-switches/]] design, using slide switches and taking advantage of harmonics (odd multiples of a half wavelength). I am also considering the merits of two antennas; eg. 40/30/15/10 & 80/20/17/12. 20m seems tricky to match length with another band.

Another idea is to make a trapped dipole for simplicity.