The kits described in this section use the understanding of antennas as surface wave transmission line (SWTL) devices together with high symmetry and electronic designs capable of high common mode rejection ratio (CMRR) to create broadband receive-only antenna systems and measurement equipment.  These designs are intended to produce practical receiving systems which can best deliver the signal-to-noise-ratio (SNR) available from incoming propagating waves, those originating from distant transmitters and sources,  to become dominant in a receive system's detector. These designs are particularly focused on the spectrum over the  audio frequency (AF) through the high frequency (HF) range.

This section describes several broadband receiving antenna systems which use active preamplifiers.  They have in common that each includes a symmetrical interface for use with a symmetrical(balanced) antenna system.  These are all  non-resonant systems intended for broadband operation having medium to high impedance feedpoint connections. Most are probe antennas  and are low Q rather than matched structures as are commonly used for transmitting.  THough the preamplifiers involved may also be usable with low impedance and matched structures  this is not a design goal.  Better solutions likely exist.

A common goal of these systems is to obtain very high CMRR so that unwanted noise and signal ingress does not degrade the incoming SNR.  The best of these designs can provide more than 40 dB better balance than conventional passive methods such as  ferrite baluns.  This extra common mode immunity is proving essential to creating low receiving  system noisefloor/temperature  which can be required in typical environments.

A Field Probe is included in this section. While not intended to be a long term antenna solution it can be a useful tool for identifying the best available location for one of the antenna systems: this will  a location that optimizes SNR for ionospherically propagated signals while minimizing coupling to unwanted  local noise sources.

Deployment of any of these receiving systems should be considered an ongoing project, not as a simple, one-time solution.  The  designs only make the goal of low receive system noise floor and maximum SNR more possible- they  doesn't guarantee it.

Some of the preamplifiers include frequency shaping or filtering to better match the reality of over-air broadcasts worldwide and the limited dynamic range of modern software defined radio (SDR) equipment.

To understand these several receive antenna systems  it may be helpful to consider that antenna systems may not behave as commonly believed and that even the theory being applied may not be what is commonly accepted.
If these assertions are surprising  and assembling  one of these antenna system kits is being considered, please read all the background FIRST.
This includes but is not limited to
A New Antenna Model

Notes on Improving Station Noise Performance

Some Thoughts on HOA Antennas

Loop over Earth Antenna

On the Response of an Active Dipole, Winter 22 RadCom+ (RSGB membership required)

Active Antenna Projects DL4ZAO

Whip_Tipps DL4ZAO (Google Translation)

The ultimate goal of the systems shown here is to come as close as possible to delivering the SNR available from an incoming wave to as receiver's detector.  For practical reasons this is never perfectly possible due to the limitations of  real components. This should be thought of as an ongoing process that is unique to each location.

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