Are you connecting the amplifier to the TX Inhibit pin of the K3 ACC port? Do you have CONFIG:TX INH set to Low=Inh or Hi=Inh? You must first set CONFIG:TECH MD ON to see it. Try changing TX INH to OFF.
>From the Expert 2K-FA manual, section 13.3: "All modern transceivers have a delay before the transmission to allow the linear to stabilize their relays avoiding damage to them and possible effects of "Hot Switching". The Expert 2K-FA has a settling time of only 6.5 msec. compatible with all modern transceivers (see the manual of the transceiver). Some transceivers have an input (called TX-INHIBIT, LINEAR, MUTE, etc..) which disables the transmission. *This input can be used with transceivers that do not have such delay *or, more generally, to improve the safety of switching." So unless you are using CW QRQ mode in the K3 (and PTT lead=0 in Win-Test), the relay should close well before the RF is output, so it should not be necessary to enable TX INH at all. 73, Bob, N6TV On Jul 13, 2017 7:58 PM, "VA2EW" <[email protected]> wrote: > Thanks guys for your fast answers and suggestions. > > After having read you, I made several tests. > > I have observed some very strange things leading me to think that the K3 > USB by itself is not involved: > > The problem occurs only when the amplifier (Expert 2K-FA) is in operate > mode and whatever the output power even 50W in a dummy load (the RF is not > involved). > > The problem disappears when I put 0 ms as well as 30ms in the "CW-PTT ON > delay" of the interface configuration of Win-test. > That delay is the time between the initial PTT ON signal and the first CW > sending. > The problem comes back when I put my initial 12ms setting. So why 0 and 30 > are ok and not 12ms...that's the strange thing? > > I'm starting to think that there is something related with the inhibit > output of the amplifier, when there is an inhibit signal at the input of > the K3, the transmission stops and we cannot hear anymore the transmitted > CW. So, maybe the USB is correctly doing its job but the inhibit signal is > hiding it. > > You could tell me :" you have found a solution so stop digging" but I do > not like when things are floating around in the station so I have to put an > oscilloscope in all that and check the timings. > > I'll tell you if I find something interesting for the reflector > > 73, Gilles VA2EW > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
