I want to start operating the 2m band while camping, but with my current setup, my antenna would be very close to the ground and ineffective. So I'm wondering, does anyone have tips for constructing some sort of tower to get the antenna higher?
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$\begingroup$ How high do you want it? If less than 30 feet or so, then you can use a guyed pole support instead. $\endgroup$– Mike WatersCommented Feb 10, 2023 at 17:24
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1$\begingroup$ not sure my idea of camping cooperates very well with the idea of carrying a stiff 10m pole, @MikeWaters, but I think camping styles might be different. I_like_python: you say "your current setup": could you tell us what that is, so that we can work off something? $\endgroup$– Marcus MüllerCommented Feb 10, 2023 at 17:41
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1$\begingroup$ @MarcusMüller That's what I did at Field Day around 1980. That was camping. :-) Three or four 10' long Rohn TV masts. 11 element beam on top, and rotatable from the ground. $\endgroup$– Mike WatersCommented Feb 12, 2023 at 19:55
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3 Answers
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Use a cheap quad-copter, or bow and arrow, to put fishing line over a tree branch, and then pull paracord back, and finally, hoist the antenna with the paracord. I do this in my backyard but I go from 15lbs. test monofilament to 50lbs. test, to paracord, then finally, for a semi-permanent installation, I end up with 1/2" rope with flexible tubing on the branch end so the branch doesn't cut through my rope.
I have as many stages as I do because I first need a light weight line for the quad-copter to lift, and then with some of my attempts going over multiple tree branches, and rough bark of the trees I use, I need something stronger than 15 lbs. test to even get the paracord over the tree limbs, and even 50lbs. test may not be able to get 1/2" rope, with all of its weight at 70' of elevation, and high resistance over rough bark; so I drag progressively stronger cords back and forth over the tree.
Also, unless you have to be horizontally polarized, just build a 1/4 wave ground plane antenna for hoisting, it will be a lot easier than finding two trees, or a pair of branches to put up a dipole.
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I just bought an MFJ-1910 33 foot pushup tower and I will be using it for my OCF 40m with tuner. It seemed the cheapest way to go for now, but I can take it to Feild or... All I need to be ready is a tri-pod. At home there is a hole in the cement right where the pole will go. I haven't measured as I just got the pole via UPS, and it's lunch time, but I have used to have a j-pole in that hole.
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If you want to do 2m while backpacking, your best bet might be a ladder line J-pole. This is light weight, and can roll up into a very small package when not in use.
To get elevation, throw it in a tree. Options include arborist's bean bag on a rope, sling shot and fishing line, or what works best for me, fishing line on a fishing pole.... (fishing in trees! Fun!)
You probably don't want to hang the antenna from fishing line, but it works quite well to get the fishing line up, and then tie a rope to the end, and pull the rope up by reeling in the fishing line.
But all this is only necessary if you can't get enough distance from a hand held antenna. Sometimes just a taller antenna on the HT is good enough. A large (1/4wl or 3/8wl) whip might work well, or you can get a half wave telescoping antenna (but beware that he extra weight can break the HT antenna connector, so use this carefully and sparingly -- you don't want to be walking around with a large stiff heavy antenna directly connected to the radio). For a few extra feet of height, use a speaker mic and hold the HT up.
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$\begingroup$ The J-pole is a great balanced solution since the overall lowest height can be higher. The aperture is not as large as a full dipole, but the additional height compensates for semi-line of sight signals. $\endgroup$– user23328Commented Feb 25, 2023 at 4:14
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$\begingroup$ Actually, a J-pole is an end fed half wave, so it is a full dipole. $\endgroup$ Commented Feb 25, 2023 at 6:29
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$\begingroup$ Electrically, yes it is a full dipole. But to be more accurate the J indicates a fold back on itself. This fold increases the characteristic impedance requiring matchng. It is not as efficient as a a dipole, only close.One definition of aperture size is the length of the span of the wires; the J-pole falls short. However, another equally true definition requires the wavefront to fully illuminate the aperture. The height of the bottom of the J pole and the matching section will get collect more energy than a dipole from a distant or occluded source than lost by the matching network. $\endgroup$– user23328Commented Feb 25, 2023 at 7:11