The AM Forum

THE AM BULLETIN BOARD => Technical Forum => Topic started by: ve6pg on April 15, 2008, 05:31:51 AM



Title: ideas fer t/r...thunderbolt amplifier
Post by: ve6pg on April 15, 2008, 05:31:51 AM
...ken, ve3maw has a thunderbolt, and was wondering about wiring in a t/r, for use with his ricebox...any ideas, suggestions?...tim..sk..


Title: Re: ideas fer t/r...thunderbolt amplifier
Post by: Pete, WA2CWA on April 15, 2008, 11:21:42 AM
You can use a DowKey DPDT type antenna relay (DK2-60).
Normally closed fixed contacts are bridged using coaxial fittings or a short coax jumper.

Wiper terminal of one side goes to antenna.
Normally fixed open side of this wiper goes to amplifier output.

Wiper terminal of other contact goes to transceiver output.
Normally fixed open side of this wiper goes to amplifier input.

Relay should be powered by some derived amplifier voltage. Voltage dependent on the type of relay coil used. DC coil is the best way to go. Amplifier off, coax relay doesn't energize when you key the transceiver.

Most modern transceiver keying circuits are low voltage/low current items so be careful of the current drawing requirements of the coax relay coil. A solid-state keying interface between the keying line of the transceiver and the coax relay coil is generally a requirement.
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands