CobWebb Antenna for the 14, 18, 21, 24 and 28 MHz Bands

Cobwebb Antenna
CobWebb Antenna for the 14, 18, 21, 24
and 28 MHz Bands
The main advantages of the CobWebb over other 5
band 14 to 28 MHz antennas are that it is small,
lightweight, strong (made from fibre glass), only
requires a single support, needs no rotator, gives full
size dipole performance on all 5 HF bands (without the
end on nulls that straight dipoles suffer from), is fed by
a single 50 ohm co-ax cable (via an in built air core
choke balun), and most important of all, it produces a
pure horizontally polarised signal with a confined
electric field. This results in much reduced coupling to
nearby conductors, so that losses and interference
problems are reduced to the absolute minimum
possible.
The CobWebb can be easily mounted on a single 20
foot aluminium scaffold pole, fixed to the wall of the
house with a couple of stand off wall brackets. The
pole can then be pushed upwards to put the CobWebb
up at 30 to 35 feet, or lowered so that it is at roof ridge
height, to overcome any possible planning problems!
All the other small multi-band commercial antennas
that are available are less than optimum. The “broad
band” folded dipoles and verticals have lossy
transformers or terminating networks in them. These
may provide a fairly low SWR over the full 2 to 30 MHz
band, but so does a dummy load! Some trap dipoles
have lossy traps and baluns, so that a nice 50 ohm
match is produced on all bands. Others have no balun
at all, the feeder cable will then need to be a particular
length to reduce feeder radiation and provide a match.
Doublet Antennas may have some gain on the higher
frequencies, unfortunately every 3 dB peak has a 20
dB null in other directions! Other small “magic maths”
antennas are available, but their performance is so
poor that you can’t even hear them on the bands, to
measure how far down they are! The many types of
vertical antennas are best avoided, unless you have
no neighbours, because of all the interference
problems.
Antenna is still in box. Never used.
Price is euro 320
Contact Lawrence (9h5ne on 99869724)
MA6V Cushcraft 6-band HF Vertical
* Bands: 6, 10, 12, 15, 17, 20m
* Gain: 1-2dBi
* Power rating:250W PEP
* VSWR: 1.2:1 (All bands)
* Bandwidth (2:1) kHz 10m (500), 12m (100), 15m (450), 17m (100), 20m (200),
* Vert. Rad. Angle: 16 degs
* Height: 4.48m
* Mast size range: 31.8-51mm
* Wind survival: 160 kph
* Weight: 2.95kg
The MA6V is Cushcraft’s newest multiband HF vertical antenna. It provides 6-band coverage on 20m
through to 6m. Power rating is an excellent 250W (PEP). VSWR at resonance is 1.2 with usable
bandwidths of 200, 100, 450, 100 and 500kHz. The antenna does not require radials and is the
perfect choice for patios, backyards and small gardens. It can be quickly dismantled and stored if
necessary.
Antenna is brand new.
Used only once for tuning & testing.
Price Euro 360
Contact Lawrence (9h5ne on 99869724)
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