The MFJ 1835 and MFJ 1835H G3TPW CobWebb Antennas
for the 14, 18, 21, 24 and 28 MHz Bands cover all 5 Bands with low SWR. The SWR at the band edges is mainly reactive, i.e. the resistive component is still near 50 ohms, so auto and simple ATUs can match it with low loss. Over 95% radiation efficiency on all bands! Radiation pattern is nearly omni-directional so you don’t need a rotator.
The five “squares” are made from white PVC covered multi stranded copper twin cable which is supported by a horizontal cross, made from white fibre glass. Each element is folded and tapped for impedance matching, so that the antenna looks like 50 ohms on all 5 bands. The small size ensures minimum windage and the low weight means that TV type brackets and masts may be used for supports. This fiveband half-wave open-loop is perfect for restricted space or portable operation.
It is a very efficient horizontally polarised omni-directional antenna for the 14, 18, 21, 24 and 28 MHz bands, with a gain of 7 dB over an isotropic radiator (7dBi). Note that this is the same as a standard dipole, although a straight dipole will have sharp nulls off each end. Up to 5 dBi gain will allow you to work DX easily -- even on QRP.
Nearly all the power fed into the CobWebb will be radiated, so the antenna will not heat up and so limit the power rating. There are no ferrites used so no intermods are produced. CobWebb antennas are not affected by the nearby environment so THEY WORK AT ALL LOCATIONS.
The CobWebb antenna is available in 2 versions:
With 1:2 balun and SO 239 (PL female) connector. Max. power 300 W PEP (SSB)
Successor of the MFJ-1835H is the MFJ-1836H 6-band antenna
Dimensions and weight are including packaging