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Portable Operating

These images and ideas are literally "thrown together" as it's easier to put a few images on a web page and refer interested folk to that site rather than keep e-mailing them out.

I have been operating portable, in one way or another, since 1977. Portable operation has usually involved either transport by, or operation from, a vehicle. This page covers my most recent operating on 23cm and 70cm, but the general principles apply to other bands.

The image above shows my 25 foot telescopic mast which is slotted into a "drive over" base plate, the mast will self support in light winds and can be used with 3 guy lines in windy conditions. The mast is the top section salvaged from an old pump up mast, the guy plate is triangular and made from a scrap sheet of 16g aluminium plate (below right). Note the spacer below the guy plate to avoid snagging the guy lines on the clamp... It is an offcut of 40mm waste water pipe. The drive over plate is a home made (by someone else) heavy duty unit that is far better than those often advertised on ebay.

The small fold up stool is used to support the mast while attaching the extension piece and the two antennas, and these small antennas are light enough to carry the mast with them fitted to the drive over plate. For a single antenna use, I can fit the antenna with the mast sitting in the drive over plate.

For anyone wanting to make a copy of the drive over plate, the dimensions are as follows:

Base plate 14" x 19" x 3/16" steel. Edges are 1 1/2" x 1 1/2" x 1/8" angle, the rectangular tube is 18" x 2 3/4" x 2 3/4" x 1/8" and is welded 2" from the edge of the base plate. There is a lip on the edge opposite the tube which has been folded up from the base, equally a stiffening strip could be welded on there instead.

The advantage of using a square tube is that it allows the mast to be held in position by means of a wooden wedge or two:

The guy lines are ordinary rope from a hardware store with spring loaded clips on the end, they are wrapped on "winders" sold by G3CWI on his "SOTA Beams" web site.

Above is shown my portable operating setup, the laptop is used for both logging and monitoring the DX cluster, it is powered by a 120 Watt 12 Volt to 19 Volt inverter by Vanson. Internet connection is via a mobile phone that is usually powered from a pocket sized "battery bank". The IC-9700 is powered from a 12V lithium iron phosphate battery of 68Ah and an MFJ-4416C Voltage booster. The silver box on the IC-9700 is a GPSDO by Leo Bodnar, it is powered from a USB port on the laptop.

Note, some laptops use a 3 wire connection for power/charging. Examples include Dell, who use an ID "chip" in the charger which is read by the laptop before it will permit the battery to be charged. Without this exchange of data the laptop will not charge, but fortunately can still be powered from a simple 2 wire adapter. The alternative is a 12V to 230V inverter, such as the Victron Energy Phoenix 12/250 (250VA), which has been tried and found to not cause interference on VHF/UHF.

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