Muting the 6000 series for using a separate transmitter

Warren Elly

I'd like to run some of my old AM transmitters on occasion, and utilize the incredible FLEX 6500 receiver..of course, I'm not interested in harming the radio...so..any suggestions on muting the 6500 transceiver for receiving only duty?? I'll be using old style dow key relays with the boat anchors and muting normally open normally closed external contacts are available. thanks!

philip.theis

There may be a better way, but set output power to zero and use PTT

Paul Christensen, W9AC

Warren, It may be possible by using some of the connectors on the rear panel. Referring to the Flex 6000 Hardware Manual (p. 28), see sections 7.14 and 7.15. 7.14 refers to TX REQ operation and 7.15 refers to the PTT line operation. To inhibit transmit, the TX REQ RCA connector is grounded. PTT (to mute the receiver in this application), is accomplished by grounding the PTT line at the adjacent RCA connector. However, the big unknown is whether grounding TX REQ will preclude PTT activation. In both instances, you'll need to control grounding of the RCA connectors from your transmitter -- and that will call for using a separate double-pole relay, or solid state switching device (e.g., pair of transistor open collectors). However, since your Dow-Key relay has ONE set of N.O. contacts for signaling, you could try and use a pair of 1N914 steering diodes. The diodes will provide the needed isolation between TX REQ and PTT. Tie the cathodes together to the signaling contact, then each Anode is connected to the respective RCA connector. Before proceeding, I would ask for Flex Radio's consent to key this way to assure there's no problem with the simultaneous keying of the TX REQ and PTT lines since that is normally a contradiction in function. If there's no objection, then ground the two connectors (using the two 1N914 diodes) and observe the result. If it works, then install the diodes into the shells of the RCA connectors. If you're not up to using diode or transistor open collector switching, then control a double-pole relay from the Dow's signaling contact. How confusing did I make this? Paul, W9AC

Warren Elly

Thanks so much Paul for a straight forward reply (really!) I'll get ahold of FLEX and see what their judgement is. After all, they have to have a way to mute the receiver version of the 6000 I'd think. Just can't over the receiver...though I'm still trying to conquer the transmitter I must admit 73 and I really appreciate your reply...

Paul Christensen, W9AC

> "After all, they have to have a way to mute the receiver version of the 6000 I'd think. To mute the 6700R in tandem with either the 6500 or 6700, I suspect they'll be able to accomplish that through SmartSDR/CAT and a common Ethernet switch? I don't know enough about their communication protocol, but anything that eliminates extra wires is a good thing! Paul, W9AC