SOTABEAMS Bandspringer Midi User manual

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The current generation of HF portable radios offer great per-
formance on the HF bands—but to get the best out of them, an
efficient antenna is required. The Bandspringer is a multi-band
long-wire antenna. The length has been carefully chosen to en-
sure that it will work with the internal antenna tuners in port-
able radios such as the K1*, KX1, K2 and KX3. It will also
work well with the Elecraft T1 auto-tuner and the MFJ port-
able tuner. Note that the Bandspringer must be used with an
antenna tuner—it is not suitable for connection directly to an
FT817 or similar radio without a tuner.
The Bandspringer is available in two versions:
• The Bandspringer Midi is guaranteed to work with any tuner on 40m, 30m and 20m.
It will work effectively with most tuners on all bands from 60-10m.
• The Bandspringer Maxi covers 80/40/30/20m and will work with most tuners on the
other HF bands too. Note: this aerial may not be suitable for 60m.
How to choose? If you have a KX1or similar radio, the Midi is for you. It is optimised for
40m, 30m and 20m—just like your KX1! If your portable radio covers 80m, you may be
tempted by the Maxi but remember it’s twice as long as the Midi at over 80 feet (25m) which
can make it harder to use in some situations. Most external tuners will allow the Midi version
to be used on 80m, although the Maxi will give slightly better results.
The Bandspringer consists of two wire elements, both are made of high quality tinned copper wire, insulated
with a yellow PVC coating. This wire type has proved a good compromise between flexibility and perform-
ance. The yellow insulating jacket makes it easy to spot on most surfaces (not snow of course!) which makes
handling much easier. The elements for the Midi version are 42ft each and for the Maxi version are 82ft each.
The wire elements are supplied wound on a Wirewinder (2 Wirewinders with Maxi) to make deployment and
recovery in the field as easy as possible.
Each element is terminated in a good quality “Banana” plug. The radiating element has a braided nylon cord
extension to make it easy to use. The extension is firmly attached to the wire at one end and has a pegging loop
at the other end.
An adapter is provided with a BNC plug and banana sockets to allow the antenna to be connected to your radio
or tuner. We stock a BNC socket to UHF plug adapter which can be purchased separately if your equipment
has an SO239/UHF socket.
The Bandspringer is supplied with two high-quality aluminium alloy pegs and two insulators (see overleaf for
instructions)
The total weight for the Midi version is approximately 327gm (11.5 oz.). The Maxi version weighs 570gm
(1.25 pounds).
*NOTE: The internal tuner on the K1 has a limited matching range on 80m and coverage of this band may not
be possible without using an external tuner.

The Bandspringer consists of two wire elements. The wires are identical in length but the
radiating element has a red banana plug and a nylon cord extension. The elements are sup-
plied on a Wirewinder and, before undoing the wires, take a moment to note how the toggle
is fastened and how the wires have been wound on the Wirewinder (note the “figure-of-
eight” method). We strongly recommend this method as the wire can be pulled off the
Wirewinders very quickly—without snagging.
Unwinding the radiating element (the one with the cord attached) is best done by starting
roughly where you want the far end of the antenna to be and walking back to the operating
position, paying out the wire as you go. The first time that you use your Bandspringer there
are some tasks to perform. Firstly at the operating end of the wire (the one with the red plug
on), you need to make a strain relief system so that wind, horses, children that might pull the
wire, won’t pull your radio away. About 30cm along the wire
from the plug, tie a knot (we recommend a loop formed with a
figure-of-eight knot as shown above). Pass a cable-tie
(provided) through the loop and fasten very loosely. The cable
tie can then be used as a pegging point close to the radio, leav-
ing the banana plug free to plug into the adapter (red plug goes
into red socket).
Next you need to get your aerial in the air. Make an attachment
point about 7 metres from the banana plug end of the wire (14 metres for the Maxi) using
the insulator (supplied). This gives you a firm attachment point
which will slide onto a SOTApole or that you can tie a cord to. You
can use a handy tree-branch or, better still, a SOTA Pole to support
this part of the aerial. Aim to get the attachment point of the aerial
at least 4 metres up in the air.
The corded end of the aerial can either slope down to the ground in
which case use a peg through the pegging loop at the end, or alterna-
tively, you can attach the far end to another elevated support. We supply a spare cable tie for
this.
The other wire is a radial. This can simply be laid on the ground. Ideally one would lay it
under the radiating element but in reality it makes little difference where it is laid. Do use it
however, as the system will not work as well without it. Plug the black banana plug on the
end of the radial, into the black socket on the adapter. Connect the adapter to your radio.
Before using the antenna, adjust your antenna tuner to give a low VSWR and enjoy! When
you pack your antenna up, leave the strain relief and support cable-ties in place, ready for
your next adventure.
Safety: Never pass your antenna wires over or under overhead electrical cables. Never
use an antenna in thundery conditions. Do not erect your antenna where it could trip
or otherwise injure others (or yourself).