DATONG ACTIVE ANTENNA MODEL AD370 SOFTWARE

2: With one dipole arm bent, antenna software 4nec2 shows local interference suppression on 24.95MHz. Moreover, if you bend the upper or lower dipole load 180В° parallel to the ground, it becomes possible to effectively suppress local interference (Fig. The aerial can be put up in many different ways вЂ“ as a horizontal dipole, in V-shape, as a sloper or vertically, which results in a non-directional characteristic and has proven particularly useful.

DATONG ACTIVE ANTENNA MODEL AD370 PROFESSIONAL

вЂњTheir dimension can be reduced for receivers with a lower dynamic range or, in exceptional cases, in quiet situations and for good receivers - a doubling the length corresponds to a level increase of about 6 dBвЂќ, says Rudolf Ille, who also developed professional receivers, like the DiRaWave 032, in addition to other electronic components.ДЇig.1: The MD300DX with BNC socket and connections for dipole elements as well as for ground. Two cables of stainless steel, each 2.5-meter-long, are connected to this box by thumbscrews. The aerial consists of some electronics with an exceptionally high IP3 of more than +30dBm, housed in a small, waterproof box (Fig. It is now offered as the MegaDipol MD300DX in the UK by Moonraker and Martin Lynch & Sons, or directly from Bonito in Germany, at prices of around ВЈ360. Last year, Rudolf Ille re-activated this type of aerial.

The last active dipole aerial produced so far came from Datong (the AD-370) some 30 years ago. Most active aerials are space-saving rod aerials or modules for smaller to larger loops with low-noise characteristics. Wellbrook aerials, in particular, continue to be a popular maker, providing an excellent range of powerful aerials. Working with receivers, which also had a low dynamic range, this multiplied the problem.Д®verything changed with the active aerials by Wellbrook, Datong and RF-Systems (DX-One). Here, at first, these aerials acquired a bad reputation because they built up great expectations using just cheap electronic components with a dynamic range that was often much too low. In the 1980s, these trickled down to the hobby scene. The concept was developed in the early 1930s, but only 30 years later electronic elements were at hand to build up real, well-performing active aerials. So, it answers the question of: вЂњHow sensitive must an aerial be to receive just the ambient noise?вЂќ This marks the lower limit of aerials with non-directional characteristics. It focuses on the Signal-to-Noise Ratio (SNR), rather than pure signal strength. Of course, aerials like this one can only be used for receiving, not transmitting.ДЄn active aerial is no magic, just pure physics. Good grounding surely has to be one of the secrets of making this small aerial into a great performer.

This can be heard over the Twente-SDR where it sits right on top of a steel-concrete building, 20m up in the air. Despite its small dimension, it provides a great performance. The passive part can be very small, like the 45 x 30 mm in Roloef Bakker's (PA0RDT) game-changing Mini-Whip.

They consist of a passive part вЂ“ the actual aerial, catching the waves out of the air by transforming the electromagnetic field into voltage and current вЂ“ and some electronics for impedance-matching to 50 О© and amplification. Active aerials are small wonders вЂ“ quite literally.

Datong active antenna model ad370