Flex 1500- PA PTT activation

Installation questions, Setup, and general information not covered in the other sub-forums
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vk2wn
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Joined: Thu Dec 25, 2025 10:14 pm

Flex 1500- PA PTT activation

Post by vk2wn »

I try to connect a power amplifier to my Flex 1500. Amplifier PTT is connected to pin 3 on FlexWire DB9 connector.
Unfortunately activating MOX on PSDR does not key the amplifier.
I use KE9NS 2.8 PSDR.
Are there some settings there I should set to activate amplifier PTT?

Tom
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ke9ns
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Re: Flex 1500- PA PTT activation

Post by ke9ns »

Open the Antenna panel in PowerSDR, and make sure the PTT Out checkbox is enabled.

And because of the "PTT out" limitations on voltage and loa, you may find you need to add a small relay on the PTT out (between the 1500 and your Amp)

If you left click on the "PDF manuals" item on the top line of the PowerSDR console screen, it will open the manual (mostly for the 5000)
Page 9 (PDF page 22) shows a PTT circuit you can use between the 1500 and your amp if needed.

Darrin
Creator of PowerSDR KE9NS v2.8, based on the Flex Radio PowerSDR v2.7.2 software.
Flex-5000, LDMOS and Titan Amps, G5RV, and Mosley TA-33 Junior
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