RX Only port - 6300

W7KHZ

Is there any way to turn one of the antenna ports into a 100% protected and fool proof RX only connection? I would like to find a way to lock out accidental transmissions on ANT 2. Would this likely require getting into the radio and installing a line to the other side of a relay? I am using amplified loop antenna systems to vastly improve reception and killing urban noise, and I want to avoid any possibility of transmitting into this antenna.

Turning power levels down to zero just won't work out.

Thanks.

KD0RC

Hi Mark, I doubt that Flex would do custom modifications. One thing you could do is to use the TX output to control a relay that would disconnect the amplified loop when you transmit. You would probably want to set RF output to zero to test it. You would also want to look into TX Delay in SmartSDR to be sure you give your relay enough time to break the connection before you send RF out of the rig.

Len

bahillen

Use the RX A port for the receive antenna.

W7KHZ

So, for the 6300 that isn't an external connection. Is that an internal connector inside the radio?

KD0RC

Hi Mark,

In the Hardware Reference manual :

7.4.10 Pin 13: Accessory TX REQ This pin is an additional transmit interlock signal input. Refer to the SmartSDR documentation for information on how to configure this input.

On page 157 of the SmartSDR Software User Guide, it shows that you can use pin 13 of the accessory port to inhibit transmit. If you make it active low on the TX panel of Radio Setup, grounding pin 13 will inhibit transmit (all antenna ports). You could wire a switch to connect this pin to ground. You will have to remember to flip the switch, but this might be better than nothing. One thought is to connect a relay to ground pin 13 any time the loop antenna is powered up.

You can also use the TX Band Settings to inhibit transmission, but you will have to remember to check or uncheck the PTT Inhibit box depending on what you are doing.

None of what I am suggesting really gets to what you are trying to do, but hopefully something here will be good enough.

73,

Len, KD0RC

W7KHZ

Len, thanks for these options to review. But you are right, these require additional steps during regular radio use.

It looks like I might need to open up the radio and see if I can find a way that I can extend out the receive antenna input to an external connection without having to cut board traces somewhere with an Xacto knife and solder on a piece of coax. If not then radio surgery. I wonder if Flex does custom mods like this somehow, on older radios?