I am trying to get the most height usage from my Sotabeams tactical mini mast and run a NY4G efhw as an inverted V. The wire is the same thin wire as the Sotbeams antennas.
Currently I use a cotter pin in one of the larger diameter sections and it works fine, however that reduces the overall length some.
I am looking for suggestions on how to run the wire as inverted V and use the max length of the mast (to the tip section), the supplied insulator is only good for running as sloper.
Any suggestions on how to attached this wire is appreciated.
I use water bottle caps for holding my wire antennas to a mast. Here is my 88’ doublet with one cap for my Tactical Mini mast and one for my 10m mast. I typically have them sitting at the top of the second section of mast, but at least with the tactical mini it is stiff enough that it would probably hold further up on the first section.
They just slide over the mast and are a friction fit. But you could definitely epoxy an eyelet to the mast like in your picture to get the most out of your mast. Just make sure it will still fit under the end cap.
Do you have access to a 3D printer? I designed and printed (in PETG) a couple of fittings for my tactical mini that can either have a wire hooked over them or support a lightweight carabena or clip.
If its not windy I use the fitting that is closed at the top so it sits on top of the mast and has a rubber grommet to hold it in place:
On both these the funny clip shape is sufficient to easily hook the wire over and it doesn’t fall out again whilst the mast is being raised. There’s virtually no weight in either of these and PETG is resilient enough (including to UV) that they should last a while (and if they break it costs pennies to print replacements). Worth asking around to see if a local ham has access to a 3D printer - I’m happy to share the files if they were of any use.
The carbon mast I use is a Comrade 600 MIFINE.
The top section is very thin and you loose some height when it bends over with even my lightest endfed wire.
I glued the top section inside of section no 2 and made it a lot stiffer.
Fully extended the pole became 5.3 metres tall or close to.
I found a length of white pvc 25m pipe about 600 long that the carbon pole fits nicely in and it is very handy to carry on my back pack but also protects the bottom section of the carbon pole when I tie it to stumps posts star pickets or what ever my tie off point will be on the summit. At a point 15cm or abt 6 inches below the top of said 25 mm pipe I drilled a hole from one side to the other of the pipe. I poke a tie off string through the hole and it allows the carbon pole to sit in there which makes the overall height closer to 6m tall for the mask. After the activation I take the string out of the hole and the carbon pole can slide down inside the tube to carry on my back pack.
Just another brain storm from
vk5cz …
I use curtain rail runners. Take off the flange, drill appropriate size hole to slip over the top of the tactical mini & attach the wire. Total cost? Almost zero
We don’t experience many wind-free activations on UK summits! As such, my dipole centres tend to sit one or two sections down from the top of a 7m mast. I go through less masts that way!
The one I get the highest is my 30m GP - the top insulator sits two sections down from the top (well one section as I’ve removed the top extremely thin section) of the 10m Travelmast.
I’ve worked the world using QRP, with good DX on 40m, 30m, 20m, 17m, 15m, 12m and 10m without putting strain on the uppermost thinnest sections of poles. I don’t think that extra metre makes much difference from the top of a hill.
Dipole centre, used continuously since 2006. 4mm posts for dipole legs. Pole mounts are made from old plastic or 0.1 Veroboard offcuts. Different poles need different sized fittings. Made from “soft” material so as not to damage soft pole material. Bottom left in brown for Life’s a Breeze 5m pole (thick and stiff sections) and top left blue Veroboard for Decathlon 5m Caperlan travel pole.
On all my mast-mounting portable antennas (linked dipoles, EFHWs, roll-up J-pole) I use a releasable tie wrap and a thick rubber band [see photo]. It takes only a few seconds to slip the tie wrap over the end of the top section of the pole and wrap the rubber band 3 or 4 times over it to make an unslippable attactment.
For my linked dipoles I also use a short length of bungee cord to attach to the balun plate for strain relief in strong winds.
I often remove the top two [flimsy] sections of my 6m and 9m poles before travelling if using the long (80/60 or 60/40/30/20) linked dipoles to prevent the pole bending over in an alarming way. I’m not convinced the small loss in height makes much difference given all the other compromises (like the far end of the dipole wires being close to the ground).
I wouldn’t worry too much about the difference between 5m and 6m for an EFHW as an inverted V for SOTA. The questions to ask before offering an answer is what you are striving to achieve by increasing the antenna height. My SOTA activations are mainly QRP and I am happy to direct most of my RF at a high angle skywards as most of my contacts are within 1,500km.
I have done some modelling of the gain and far field plots versus antenna height for an inverted V. The impedance drops, while elevevation angle and losses increase as you reduce the height. The chart below is from my MMANA modelling of a SOTA Beams linked dipole on 20m.
If the objective is to increase DX potential a vertical may be a better option.
I use an inverted L. Run the wire through the eyelet and down the pole to your transformer at the bottom of the pole. Tie the other end of the Inverted L to a tree. I realize some folks don’t have trees, you could use a stake instead. This configuration results in minimum coax feed, I use a 3ft (1M) piece of RG-174. Or you could build your transformer in a BNC connector and plug straight into the radio.
