Nevada Radio

MFJ 1708B

RF Sensing Tx/Rx Switch






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RF Sensing Tx/Rx Switch

Enjoy using vintage tube type separate transmitters and receivers?  It was a real chore to switch your antenna from transmit to receive and back -- it still is!

Automatic Tx/Rx switch senses transmitted RF and switches your antenna from receive to transmit using a relay.

It shorts your receiver antenna input to ground to protect your receiver. It also provides an auxiliary contact closure to ground during receive (opened in transmit) for an "On-the-Air" sign or other use.

Instead of using RF sense to switch the antenna, a control line input lets your key/keyer or PTT line switch the antenna.

  • An adjustable time delay circuit gives you delayed switching. 
  • Works on all modes -- CW, AM, SSB, FM, and digital modes.
  • Power rating 200W SSB PEP.
  • Size 4 W x 2 5/8 H x 1 1/2 D inches.
  • SO-239 coax connectors for antenna, transmitter, and receiver.
  • Control input, auxiliary contact closure to ground, time delay screwdriver adjustment, power jack.
  • Requires 12 VDC

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