Although popular in other countries, monoblock LNBs haven't been adopted with such enthusiasm in the UK. A monoblock LNB provides two feedhorns, two LNBs and a DiSEqC switch all in one package for receiving signals from two satellite positions at once on one dish.
The two feedhorns are fixed at the right spacing for reception of the two satellites (usually Astra 1 at 19°E and Hot Bird at 13°E) on a standard offset dish using the principle of multiple focal points from a normal satellite dish.
A new range of monoblocks from German manufacturer Lemon may well change UK perceptions of monoblock LNBs. The LEM-40MONO is the basic model. It is compact and follows the trend of hiding all the metal casing of the LNB inside an outer plastic case that looks prettier (and a waterproofing cable boot is supplied).
Foremost in its specifications is a (frankly) incredible 0.2dB noise figure. Quite how this is measured and exactly what it represents is unclear, but what is certain is that this monoblock is startlingly low-noise.
It's designed for reception of satellites 6° apart - specifically Astra 1 and Hot Bird. The size, shape and spacing of the feedhorns also assumes a 'standard' offset dish with a focal-length-to-diameter (f/D) ratio between 0.6 and 0.7 (which includes most 60cm, 80cm and 1m offset dishes available in the UK).
There is nothing on the monoblock to indicate which feedhorn is number one. However, because Eutelsat invented DiSEqC, it's normal that the Hot Bird feedhorn (the left-hand one looking into the feedhorns) is the default - and so it is with this model.
The monoblock was tested on an 80cm offset dish. The dish was aligned on Hot Bird with the primary feedhorn clamped at the focus. You can just as easily clamp the other feedhorn at the focus and align on Astra 1 (and you may want to in the north of the country) but only if you have a meter that can achieve the necessary DiSEqC switching.
In theory, the angle of the monoblock in the clamp should be adjusted to achieve the correct elevation difference between Astra 1 and Hot Bird, decreasing as you go farther north. However, this twisting would also affect the skew adjustment on both halves of the monoblock (and vice versa).
