My SOTA Link Dipole.

My favorite antenna for SOTA is a home brew 40/20 link Dipole with Extensions for 80 metres. I carry a 7 metre Squid Pole to the summit as well for support, and set it up with the end strings right to the ground to get the best inverted V config with a good degree angle for the dipole. Loops on the end of the strings are used to tie off to rocks mostly, saves carrying tent pegs on summits where the ground is usually too hard to use pegs any how.

 

This is the rolled up Dipole and 80m Extensions

10m of RG 174 feed line wound through a toroide type 43 to limit common mode on the coax. I made the winding first then fitted the BNC line socket after the Choke was wound. 6 turns one way cross over 6 turns back the other way. The Loop on the string ends are used to make a slip knot type loop around a rock to hold the ends of the dipole in place. Plus it comes in handy for when you want to wind up the antenna.

To fit the antenna to my Squid Pole I came up with a grey plastic wall plug that fits nicely in the end of my pole, it has never failed in all the time I have used it. Drill out the wall plug, poke the string through and tie a knot. When it fits in the top the string is slightly compressed and it holds in place nicely.

The reason for the yellow zip tie around the top section serves a good purpose. When the squid pole is fully collapsed the smallest section would always fall down inside the other sections. The zip tie leaves some of the smallest section sitting inside but above all the other sections so I can get a hand on it to fit up the antenna. Now if you bungee up your squid pole to a post or stump with out first pulling out the top section you have to undo every thing to get it out wasting time. With the zip tie on top its just sitting nicely in the top of the pole waiting for you.

 

Time to explore my link methods and reasons. On most summits I visit there are lots of rocks and short prickly bush or grasses to tangle or break things if you are impatient. The antenna is most vulnerable when putting it up, when I made my antenna I only used one Alligator Clip per link. On the Highest frequency end I cut an inch off the outer case and tinned the wire with solder then tightly wrapped it around the outer case on the yellow wire. This give a good connection for the clip to grip on when closing the link and one less thing to hook on stuff causing a fail if I had used two clips per link.

This is the 80m extension hook up point on the very end of the 40m section of the dipole. I chose Bullet connectors for this job and a plastic fitting to give extra support to the extension wire. The small knot tied in the 40m end string is there as strain relief for the extension wire when the antenna is up. Plug the bullet connector into place then place this green fitting behind the knot on the string then run out you extension wire.

With an 80m antenna on a summit it becomes a big span of wire so in my case I set up the 40/20 inverted V like normal then add the extensions to the already supported dipole leaving all support strings hooked up to rocks or what ever is my end support. When you finish on 80m you can just unplug the extension and leave it in place until you roll up the antenna at the end of the activation. I usually roll up my extensions first then the rest of the antenna last leaving less chance to get thing caught up on the floor of the summit.

Activation done lots of chasers and S2S its time to roll up the antenna and head to the next summit.

   

Start with extensions first with the loop on the end of the string over your Pinky finger and roll in figure of 8 pattern around Finger and Thumb.

 

 

With the 40/20 dipole start with the support string first and roll until a couple turns of the dipole end is on your hand as well, this is where I tie a simple knot around the first part.

  

Take the wound up string section off you fingers and place it between your fingers at the back of your hand then continue rolling the rest of the antenna on in the same figure of 8 pattern.

  When both bundles are rolled up then I place the tie through the green fitting. Now my main reason for rolling it this way is again to help with erecting the antenna on the next summit, it is tangle free and less likely to snag on the way up and you can visually monitor for snags.

My coax is rolled up by the same method I roll up all coax that is on the ground at the radio end and tie it off then when the Squid pole is lowered I roll up the rest and tie it off with a different tie. It helps to keep it safe from big feet stepping on it when putting up the antenna. Yes of course I am speaking from learned experiences when it comes to SOTA antennas on a summit I have the tee shirt remember.

  Nice and Compact for my SOTA bag.

Hope this helps someone in their Quest for Mountain Goat.

Thanks to George KX0R for showing me this method of rolling up an antenna.

Regards

Ian vk5cz

 

 

 

 

 

 

 

 

 

 

This entry was posted in SOTA.

One comment on “My SOTA Link Dipole.

  1. VK4FR/VK5FR says:

    Nice tip on the coiling of wire on your hand. An old bloke taught me that once who needed to be able to roll an antenna, deploy an antenna and tx cw on the move…

    Cheers
    Chris
    VK5FR

Leave a Reply

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

WordPress.com Logo

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

Google photo

You are commenting using your Google 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

This site uses Akismet to reduce spam. Learn how your comment data is processed.