ALC-1 protection circuit for linear amplifier in connection with Power Master PM3
This is the best way to shut down an amplifier after an VSWR alarm, or a power alarm problem.
Your ham radio antenna system can subject your transceiver and/or amplifier to sudden high SWR conditions due to intermittent connections, breakdown of antenna components, or even birds landing on your antenna. Or maybe something has changed in your grounding system due to weather and you are transmitting without checking first. So how can you protect that expensive transceiver and amplifier from these events?
Enter the Array Solutions ALC-1 Transmitter Inhibit controller. This unit interfaces between your amplifier’s ALC output, your PowerMaster PTT connections, and your transceiver’s ALC input to provide fast, rapid protection of your transceiver and amplifier when a sudden high SWR event occurs.
The Array Solutions PowerMaster provides a PTT feature which can be used to unkey your amplifier when an SWR reading above a user-selectable pre-set limit occurs. However, when this occurs your transceiver’s output can be hot-switched since the amplifier is being unkeyed while your transceiver is still putting out full power. Further, some amplifiers are designed such that they do NOT unkey as long as RF is present so as to eliminate the possibility of amplifier hot-switching until the RF input has completely decayed to zero. So these amplifiers can be subjected to a high SWR which could possibly damage them.
The Array Solutions ALC-1 Transmit Inhibit controller eliminates these potential hot-switching or high-SWR operating problems by instantly applying a cut-off ALC voltage to your transceiver when the high SWR event occurs. This turns down your transmitter RF power faster than amplifier RF relays can operate, ensuring that no hot-switching can occur.
Not using the amplifier ALC? The ALC-1 will still shut down any transceiver that has an ALC input.