Hi everyone, for portable use I have always been throwing heavy home-made dipoles into trees, usually without achieving nearly the height required for decent gain at useful angles (I’m thinking of the high bands, 30m and shorter). I thought I should look over how to optimize the antenna setup a bit, while keeping things portable and QRP. Now I am looking at getting a backpack-friendly (max about 70cm) fiberglass pole to use with verticals and hopefully also inverted-V antennas, either end-fed or center-fed. My question is, are there any portable 10m masts out there strong enough to support an inverted-V at full height, using light wire? If anyone has done this for center-fed antennas, I would also be interested in what kind of feeder you use. In particular, is it possible to support a thin ladder line to make a lightweight doublet?
The SOTABeams Band Hopper IV is a linked dipole using their lightweight cable. Their 10m compact travel pole is quite sturdy and will support the dipole on the 3rd section down, so at about 9m. This antenna is fed using RG174 lightweight coax cable which has approximately the same losses at HF as RG58.
Even if you are not in a position to buy from SOTABeams it is well worth looking at the design of their antennas, for example the core based 1:1 balum at the centre, and the way in which the coax and guyline are wrapped around a single winder.
Hi Robert,
I use RG-174 or RG-316 coax for the feedline. I have not heard of many SOTA activators using ladder-line while portable.
As for masts, I tend to use 6 metre ones as a compromise between height, weight and packed size. I do have a DX-wire 10m travel mast that packs small but to do this the walls of each section have to be thin, which can lead to cracks developing if the mast ever collapses into itself. If you can carry a larger packed size 10m mast, the sections will be stronger.
In any case, the top section(s) are rarely usable as they flex too much so the best I have found is being able to get the feed point up at around 8.5-9m on a 10m mast.
If running QRP you can get away with no balun at the feed point, which reduces weight (but there are also lightweight QRP-only baluns available from SOTABeams and elsewhere).
If you intend to build your own antenna you may want to take a look at https://www.sota-antennas.com/
which has design tools and length calculators for several different types of antenna.
the SOTAbeams compact lightweight 10m (same as DX-wire 10m mini) carries an centre fed inverted v antenna (10 - 60 m) up to 7 - 8.5 m, depending on the antenna’s weight.
I also use the light 10m mast from DX-Wire… but with 0.14mm² wires… I think it is too unstable for these thick wires. It tends to collapse if the elements are not fixed. And even with my thin wires, I can only use the top two elements with a vertical antenna…
There are good, stable masts from Spiderbeam, but they are longer and heavier:
Echoing what Armin says. The Spiderbeam masts are a different (better) class of mast compared to the other ones that we have talked about. They are a lot stronger but with strength comes weight.
Considering the quality and finish of the Spiderbeam masts, they are not a lot more expensive.
As always with portable operations a compromise needs to be found between strength and carry weight and size. The SB one that Armin links to looks like an interesting compromise and is just a couple of centimetres longer than your wished-for closed length.
Hi Robert,
Although there are compact 10m poles I wouldn’t be too obsessed with that height.
Many people (like me) use lightweight compact fishpoles around 5 - 6 m high with great success for activation.
Concerning the wire, the yellow one from SotaBeams is strong enough and very very light to avoid bending of the pole, despite we don’t use the very last section of the pole which uses to be too thin.
If you intend to use a Doublet antenna , I know @N6AN David is using a great one homemade with cheap Ethernet cable.
Simply strip the cable to get on pair of them to use as a feeder from your rig up to appex of the antenna. Seems to be working great with affordable losses and the Tuner in the rig makes it multiband with ease:
Jackite makes a great 6 meter fiberglass pole that I use to support my 8 meter on each side doublet. I feed the doublet with about 7 meter of cheap tv ribbon balanced feeder. The Jackite pole has a little thicker tip then most 20’ fiberglass masts so it works great to hold the whole thing up. My kx2 autotuner will tune all bands, 10 thru 40 meters, no problem. I’ve used versions of this for over 10 years. Have tried EFHW and random wires but always end up coming back to the doublet fed with balanced line. The jackite is a great pole but is about 1.3 meter when collapsed. However, this is a perfects size to use it as a walking stick which is very handy as my 3rd leg during steep bushwacks. Search amazon for jackite to see the pole.
If it is an actual mountain peak you are on, height may not make much difference. The foreground is falling away from the antenna. It may think it is MUCH higher than it is. The difficulty of a pole supporting a center fed feedline is why I switched to an endfed halfwave.
Thanks everyone for sharing your experiences, and the many useful suggestions!
@DL6GCA and @DD5LP – I have been looking at the 10m Spiderbeam “mini” pole, and it seems like a reasonable compromise for me (mostly shorter tours), as long as it is strong enough. Like Ed and also Ignacio say, others may make a different tradeoff between size/weight and performance, depending on how far you need to carry things. I have had great contacts with my 30m QCX (3W out) and a dipole up maybe 3 meters. But raising the antenna to 10m up would mean about 6dB more gain. Add another dB or so from using low-loss feeder over RG-174/RG-316, and I would rather spend those 7dB getting above the noise floor of a few more stations, or going QRPp and doing the same contacts with milliwatts instead. But I will certainly save those neat doublet ideas for an ultra-portable setup! Mark, I will have a look at commercial designs as well to see which ideas are worth borrowing.
And good advice from @KT0A finding a dual use (walking stick) for a longer model, I hadn’t thought of that!
@KT5X - unfortunately I live in a rather flat area, so I suspect most operating will be done at low altitudes. But thanks for the reminder, I should make better use of the hills we actually have.
