Tag Archives: LZ1AQ

LZ1AQ Evaluates Impact of the Height Above the Ground on Mag Loop Performance

Source: LZ1AQ

Many thanks to SWLing Post contributor, Harald Kuhl (DL1AX), who shares the following article on LZ1AQ’s website:

Published on: 2018/11/20, Rev. 1.0 July 2018, Rev. 1.1 Nov 2018

Author: Chavdar Levkov LZ1AQ

Setup

Two identical small loops were placed one above the other according to Fig.1. One of the loops is very low – almost on the ground. The other one is placed at height which usually is used by the loop users. Two AAA-1C wideband active antenna amplifiers were used. Their gain difference was not more than 0.3 dB. The feeder was FTP cable each 20 m long. No cable baluns were used. The outputs were connected through two way antenna switch to a SD RX (Perseus). I used a measurement technique described in – A Periodic Switching Technique to Compare Receiving Antenna Performance in the Presence of Strong Fading. This is a precise method to compare two receiving antennas with real sky wave signals and the resolution can be less than a decibel. The idea is to switch periodically between two antennas and to estimate their difference on a calibrated graphic strength meter of a SD radio.[…]

Click here to read the full article.

I’ve often assumed height had little effect on the performance of an HF loop antenna–this evaluation seems to support that theory. Thanks for sharing this, Harald!

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The AAA-1C: An affordable loop antenna amplifier kit

Active-Antenna-the-kit-product-7

I recently stumbled upon the Active Antenna Amplifier (model AAA-1C) by LZ1AQ. At 87.00 EUR, it’s a pretty affordable and flexible solution for those who would like to design or use a loop antenna.

According to the website, it packs a lot of features:

  • 4 remotely switched modes (Loop A, Loop B, crossed parallel loops A&B and dipole)
  • Each mode can be switched immediately
  • Good sensitivity and a flat frequency response
  • High dynamic range
  • Protected input from strong signals
  • High immunity to local noise with balanced amplifiers and balanced feed line
  • Balun transformer coupling for common mode noise reduction
  • Extensive documentation manuals with detailed description how to build your own small antennas

The amplifier is described as a kit because you must mount the board, wire up the antenna and set up remote switching yourself. It appears the SMT board comes pre-populated, though so I’m not sure if any actually soldering is required (perhaps someone can verify).

AAA-1B kit components

AAA-1C kit components

Click here to download the mounting instructions (PDF).

I’m tempted to purchase one this winter for use on mediumwave.

Click here for more info about the AAA-1C at LZ1AQ’s website.

Have any SWLing Post readers built and used this amplifier? Please comment!

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