Yes, I do want to go that route. Don’t need the high speed switching anyway. Think that the PTT/Keyline loops thru J8 so going to jump on that and use a sample to drive the Dow Relay, don’t matter what the relay takes being think I can
whip up a driver circuit for the relay that way.
In the RF-1110 on the controller card the PTT, Shutdown and ATU interlock are all summed together and drive a op-amp that controls the amplifier operate exciter operate line and they have a capacitor (C12) that can be jumped in and out
that provides a small lag between when the PTT line goes low and the operate line becomes active, when the operate light comes on. So by having the relay controlled by the PTT line and C12 jumped in there will be a slight delay between when PTT is pulled low
and operate goes high that will allow the relay to change state.
The good thing about using J8 is you also have the +26 volt bus and ground available for working the relay. Figure a PNP transistor controlling a high current NPN and a couple diodes may be just the thing for driving the relay. If the Dow
Relay has an external set of contacts can use that to keep the Exciter operate voltage off the exciter until the relay is closed and that would be an additional failsafe. Both Exciter operate and PTT interlocks are available on J8
Ray F/KA3EKH
From: [email protected] <[email protected]>
On Behalf Of KD2OM via groups.io
Sent: Tuesday, November 30, 2021 7:08 PM
To: [email protected]
Subject: Re: [HarrisRadio] RF-1110B getting closer
It is a Dow-Key with a contact that shorts the RX side when TX is engaged. I have one if you want to go that route.
Steve KD2OM
On 11/30/21 10:35 PM, Nick K4NYW wrote:
