Hi Bill from personal experience using JT4 on 3cms I have taken out the Rx GaAs Fet first stage a couple of times where it has hot switched, just 5W. I had additional hardware to sequence. With low power at lower freqs not so much a problem as power leakage in to the receiver is unlikely to cause damage. But VHF+ when used for MS etc, where power is used hot switching is a problem. RF arcs on relays will eventually destroy contacts, ALC , high VSWR protection help ,but the fastest fuse has three legs :) Once the fast modes are added to WSJTX it may get noticed
Thanks On Mon, 16 May 2016 23:06:12 +0100 Bill Somerville <g4...@classdesign.com> wrote: > On 16/05/2016 22:50, Richard Bown wrote: > > Its putting a tone on the unused audio channel when in Tx > > So if data was on the Right channel, put an audio tone, doesn't matter what > > frequency, > > on the left channel (TX Mode only ). > > Has the advantage on simple rigs that you can rectify it, diode and a cap, > > and then use the > > recovered DC to switch the PTT, and if the tone is sent before the data , > > everything is already > > in TX mode so no hot switching. > > Hi Richard, > > understood, I had not come across such a feature before but I can see > that it makes sense for a lightweight PTT method with some advantages > over VOX. I expect the benefit is marginal given that switching PTT with > audio present is not really "hot switching" as almost all rigs that I > know of (some Icoms with ALC design issues being a notable exception) > have no issues switching to send when there is Tx audio present at the > modulator. > > I need to think about this a bit as to implement it cuts across the > audio and rig control components which both run in their own thread. The > implementation would have to be carefully designed to maintain thread > safe operation within WSJT-X. It is certainly doable but I would be a > little concerned that the extra benefit would justify the extra > complexity. It is a shame that modern PCs no longer have parallel ports > as a parallel port can easily be used as a GPIO port for this sort of > requirement and this is already supported by Hamlib. > > 73 > Bill > G4WJS. > > > ------------------------------------------------------------------------------ > Mobile security can be enabling, not merely restricting. Employees who > bring their own devices (BYOD) to work are irked by the imposition of MDM > restrictions. Mobile Device Manager Plus allows you to control only the > apps on BYO-devices by containerizing them, leaving personal data untouched! > https://ad.doubleclick.net/ddm/clk/304595813;131938128;j > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel -- -- Best wishes /73 Richard Bown Email : rich...@g8jvm.com HTTP : http://www.g8jvm.com nil carborundum a illegitemis ################################################################################## Ham Call: G8JVM . QRV: 50-432 MHz + Microwave 23 cms 140W, 13 cms 100W & 3cms 5W Maidenhead QRA: IO82SP38, LAT. 52 39.720' N LONG. 2 28.171 W QRV VHF 6mtrs 200W, 4 mtrs 150W, 2mtrs 400W, 70cms 200W OS: Linux Mint 17.3 x86_64 on a Dell Inspiron N5030 laptop ################################################################################## ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
