This is a brief look at my portable vertical antenna setup. It is far from an ideal antenna but there are a number of advantages to a vertical system that is quick to deploy and pack away. The availability of an SGC SG-211 auto ATU (which I’d previously acquired for loft antenna work that has been delayed) and a sturdy camera tripod have led me to this configuration. Some factors in my decision process:
- Quick setup/ teardown (only short operating windows are available)
- Small footprint, no reliance on trees or other terrain constraints
- SG-211 already in hand
- Opportunities for experimenting with the radial system
The antenna is a 12 foot long telescopic (7 section) MFJ whip with a 3/8″ thread at the base. This is tuned by the SG-211 ATU against a single radial which is an 8m tape measure. The MFJ whip appeared to the longest available telescopic whip although still rather short most amateur HF bands. The single 8m radial is far from optimal but is enough to enable the ATU to get a match on all bands down to 7 MHz. Remember the emphasis here is on getting some kind of signal on the air and working on improvements from there. My first QSO on this setup was with EA1DST in Spain, a distance of 1200km with 5W PSK on 20m. I post this as some thought went into the details of how I’ve mounted the antenna to the tripod and hopefully it may prove useful to others.
The centre column of my tripod can be reversed (upside down) to allow camera positioning closer to ground level, a common feature in enthusiast camera tripods. The tripod legs can also be moved out to wide angles to provide extra stability in windy conditions (although I wouldn’t consider setting this up in anything stronger than a moderate wind).
I reverse the centre column for antenna work and mount the base of the whip alongside the upturned centre column using quick-release bicycle seat clamps. I tested the centre column in a bicycle shop and found these clamps to be a good fit for the diameter of my tripod. The assembly is completed with a bit of insulation around the antenna and a couple of jubilee clips to fix the seat clamps to the whip. A flying lead between the whip and ATU is fixed to its base on the 3/8″ thread.
Another detail of the system which may be of use is the pouch I use to hold the SGC SG-211 ATU. A wide range of useful pouches are made for attachment to military webbing systems. A particular design for medical kits known as a ‘trauma pouch’ is a near-perfect fit for the SG-211. It fits into the rear compartment and there are two front compartments which I use to carry the tape measure radial and perhaps more/other radials as the system evolves. A bit of padding at the bottom of the rear compartment raises the ATU to allow easy access and I extend the connections from the bottom of the ATU up to 4mm banana sockets for quick connection. I have reversed the SG-211’s top cover so that the exposed edges of the top cover provide some additional protection to the connections which are at the bottom of the compartment.