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Active Antenna Amplifier Relay Control

active antenna amplifier relay control

Wideband loop amplifiers are easily automated with active antenna amplifier relay control, all for a few dollars.

My next step in computer control of my diversity reception involves my wideband loops. As you know, I use a pair of Active Antenna Amplifiers from LZ1AQ. My 100′ loop array work great for simple beamforming and noise cancellation.

Recently, I came across a blog article from VE2HEW demonstrating how he automated his loop switching using a microcontroller. So, rather than reinvent the wheel, I just used his approach.

Switching between the four LZ1AQ loop modes requires three relays with a common ground. So, my Sainsmart 8 relay module lets me control modes of two loops, plus a couple of relays for power. You can see the result above.

Wiring kept in mind defaults with the relay normally closed connection. My main east-west loops are switched on by default, as is the power. So relays only have to be activated for the other three modes and to power off the amplifiers.

Again, all of the switching logic is provided by my Arduino Mega. Amplifier outputs run to a pair of inputs on the antenna matrix switch described earlier. So, now I have retired my DIY rotary switch control built a few years ago.

Active Antenna Amplifier Relay Control Box

One more, my enclosure is 3D printed. My amplifiers and relay modules are mounted with plastic standoffs.

Since LZ1AQ amplifiers use six pin connectors for mode control, I bought a bunch of XH2.54 6Pin 1007 24AWG Single End 15cm Wire To Board Connectors online for a few dollars. With these, connecting the amplifier boards to the relay terminals is quite easy. You can use a Dremel to file down the connector housing keys as they are not needed.

Finally, some heat shrink was used to arrange the wire runs neatly.

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