Activating 160m

Andrew VK1AD had posted some VK SOTA stats for the year 2016, looking these it was obvious that no one had activated on 160m in VK.

I made comment about this on the VK SOTA yahoo group, this then turn into a challenge with a weekend selected for 160m activating.

The selected date of April 1st gave us all enough lead time to investigate antenna options. For me there seems to be two stand out choices, a load vertical with top hat or a 1/4 wave Marconi antenna. After much consideration, I settled on the Marconi as I felt it was a little easier to build and setup in the field.


160m Marconi

To support one vertical section I use an 11.5 meter fiberglass pole for DX wire.


11.5m pole sitting in old Guy point

After some research on the web and field testing at home I used two radials of ~24 metres, this length was calculated using the suggested 60% velocity factor for wires lying on the ground.

The next challenge was to select a summit, I needed one with plenty of room, but as this would be an evening activation I also needed one that I was happy to return from in the dark. There a couple of local choices I felt fitted this criteria and I selected Mt Big Ben as it had plenty of cleared and flat area around the Comms sites for such a big antenna.


The Elecraft T1 was used to improve the match on 160m and allow opertions on 80m and 40m


Plate showing two radials (red) and the vertical wire (green)

As can be seen in the photos I made up a simple Perspex plate with a few banana sockets to too allow easy connection of wires in the field, room was also left for a loading inductor should  I wish to include one.

I was on site at Mt Big Ben and set up ready to work the first station by 1600 (local).

In the end there were 8 stations and with a total of 56 summits 2 summits logged on 160 in the SOTA database.

Now like the odd sota activation this one does not have an entirely happy ending….

To support the 11.5 m squid pole I had slipped its base into a hole left behind when an old guy point had been removed. The hole was around 1500mm deep provide a great support for the squid pole. However I had not taking into consideration that the cap on the base of the pole was not securely attached, in fact it was just a push on cap. So..

When it came time to pack up the squid pole the bottom cap came off and remained in the hole, this also made it difficult to recover the squid pole as the sections simply wanted to slide right through and out of the bottom.

In the end I recover the pole, but the cap remained behind.



The hole after the water was pumped out

However I was not going to give up that easily on the loss of the cap, so I did end up getting it out of the 150mm diameter pipe, and it only took two more visits to the site, a replacement rake for the garden and $20 on a 12v pump to pump the water out that filled the hole this allowed me to see the cap, and then to hook with what was left of the garden rake after I modified it to fit down the hole.


The recovered Cap and tools

The 160m activation was great fun, whilst I would love to do a day time activation on 160m AM, I am a little too remote to get enough stations. I do have thoughts of another evening activation, this time maybe from Mt Hotham.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s