** In modern radios, R/T speed is the same whether one uses VOX, PTT,
or the SEND switch. Typical R/T & T/R switch time is currently 5 - 7mS.
In SSB or AM mode, after the R/T switch time, whatever sound the
microphone picks up appears as RF in the output. If the amplifier relay
isn't fully closed and its contacts haven't stopped bouncing when RF
drive arrives, the contacts will hot-switch. In other words, the
amplifier needs to switch faster than the radio so it can be fully
prepared for the arrival of RF.
- However, when RF-actuated T/R switching is used in an amplifier, the
amplifier relay does not begin to close until RF is already coming down
the pipe. Thus, hot-switching is inevitable. The only fix is to convert
the amplifier to the old, traditional way of letting the transceiver
control the amplifier T/R relay. This method signals the amplifier relay
to start closing 5 - 7 mS Before RF starts arriving so it can be fully
closed. // Just what the inventor of RF-actuated switching was thinking
when he invented it is way beyond me. Or, maybe he wasn't?
>Ok, is it possible to hot switch the amp when
>using the SSB mode? I don't think so, unless you
>"switch" right in the middle of a loud vowel sound?
>Correct?
>
>73, Jim KH7M
- Rich..., 805.386.3734, www.vcnet.com/measures.
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