The antenna


The antenna currently in use is an home made 8m 0.4 F/D dish, with a reflector built with a 12x12mm stainless steel mesh. After some measurements the estimated gain is around 38dBi, corresponding to 2 ° beam width, with an illumination efficiency of 55%.

The feed is a VE4MA linear polarized for the 21cm, with a choke ring to reduce the illumination of the dish at its border and to get a better G/T factor.



The low noise preamplifier is a double stage with a NE32584 PHEMT at first stage. It gives 30dB of stable gain with a noise figure of 0.3dB. This keep all the system pretty “cold”.
A further amplification stage, with the MGA62563 excellent MMIC by Avagotech, is placed before the down conversion 21cm receiver, after the coaxial cable that comes from the antenna to the receiver room.