PTT Lines


Andy G4JNT
 

I haven't been following the thread in detail, and can't be bovvered to search back.
Is there a need for extracting separate PTT control depending on band / freq / whatever ?
And if so, on which rigs is it wanted /

Or is it a totally different matter altogether ?



Paul G4KZY
 

Hi Andy,

In the case of the IC-9700 it can receive on two bands at once.  So it is designed for operating on more than one band at the same time and you can imagine that people will have stuff like linears or uW transverters for more than one band all connected and powered up at the same time.  This is especially true because the IC-9700 has dedicated antenna connectors for each band.   So a single PTT output is a bit of an irritating shortcoming.

It is really not difficult to make a gadget which can listen to the CI-V and switch the single PTT signal from the radio out to one of three outputs.  The Dx shop have a handy box that does just that.  I understand there are several others who have published designs which do the same thing.

Personally I like the old fashioned approach of using a switch - but then you have to remember to manually move the switch depending on which band you are transmitting.

73,

Paul


Andy G4JNT
 

Just what I was thinking, and wondering which rigs would require such a gizmo - hence how many CAT protocols to cater for.

CI-V is a headache - unless you implement a scheme that ignores addresses.   I did a CAT controlled downconverter once, using CAT commands to tune a Fract-N synth for the LO tuning in 1Hz steps.  I chose Icom CI-V because I had an IC746 to test with in parallel.    Several people advised using Kenwood protocol and I wish I'd listened to them.  The CI-V was a real mess to work with.    G3WDG is using that design on a synthesised LO for his IC202 for microwave transverting.   WSJT-X controls the synth via the Icom compatible CAT to allow for EME Doppler tracking.

Now, having got rid of the IC746 and got the Elad, that uses an enhanced Kenwood CAT command set so I should have listened to the others back then.  Not  going to bother rewriting the PIC code for the upconverter as it is no longer needed for what is was designed for and now just serves as a fixed 739.00005 to 28MHz converter for QO-100 



On Tue, 13 Apr 2021 at 13:08, Paul G4KZY <paul.g4kzy@...> wrote:
Hi Andy,

In the case of the IC-9700 it can receive on two bands at once.  So it is designed for operating on more than one band at the same time and you can imagine that people will have stuff like linears or uW transverters for more than one band all connected and powered up at the same time.  This is especially true because the IC-9700 has dedicated antenna connectors for each band.   So a single PTT output is a bit of an irritating shortcoming.

It is really not difficult to make a gadget which can listen to the CI-V and switch the single PTT signal from the radio out to one of three outputs.  The Dx shop have a handy box that does just that.  I understand there are several others who have published designs which do the same thing.

Personally I like the old fashioned approach of using a switch - but then you have to remember to manually move the switch depending on which band you are transmitting.

73,

Paul