Correct settings for TX Delay and RCA TX1 with an external linear amp

PhilM

I have been using my FLEX-8600 with an SPE 1.5K-FA linear with the following settings

RCA TX1 set to 0 ms

TX Delay set to 12ms

This is based on the Amp's requirement for a 6ms delay for its internal relays to settle down.

Does this look good?

The manual I was looking at was for the 6000 series radio, I am assuming it is very similar to the 8600 requiremennts

Phil, NC3S

PhilM

I think this section of the manual will explain why I chose those settings

"For external amplifier use, the delay should be set to zero for any output that keys the external
amplifier. This will ensure the relay will follow the PTT signal exactly.
The TX Delay setting can be used if the external amplifier has slow T/R relays and requires a longer
time between PTT and RF Emission. Unless you are noticing problems with the radio emitting RF
before the amplifier has switched to transmit position, you should leave the TX Delay set to zero."

The "RCA TX1" line is the signal to the external amp to make and settle down its relays, at the same time the delay for "TX DELAY" begins in order to wait for the amplifier relay to settle down, with a safety factor of 2X.

Phil, NC3S

Ken Wells

Leave the TX1 (or TX2, TX3) Delay at 0

Set TX DELAY to whatever is needed to p[revent "Hot-Switching" the amplifier relays with RF already flowing from the radio.

This can be 10, 15, 20, or more, depending upon your amplifier, its relay speed, and whether you have a second relay as a "buffer" for the Amplifier's PTT (which would need to add additional TX DELAY)

NOTE: I also Recommending using a CW DELAY (Hang Time) that is at least as high as the TX DELAY. if not much longer, unless you have a fully QSK amplifier.

PhilM

OK, thanks. I'm using a SPE Expert 1.5K-FA linear. The manual says it supports QSK and that its relay requires 6ms to settle down. I assume doubling that for a value of 12ms would be a good safety factor.

The amplifier has not issued any error messages, so I assume all is good with the QSK.

Phil, NC3S