[Elecraft] K4 Use Case Question - Support for multiple instances of WSJT-X

[Wayne Burdick]

This will work with either a K4 or a K4D. The VFOs can be on the same or different bands. 

If the two receivers were on different bands, and you only had one antenna, you'd want to make VFO A the higher-frequency band. This is because with a single antenna, both receivers would be sharing the transmit signal path, which includes low-pass filters.

Suppose VFO A is on 20 meters and VFO B is on 40 meters. Both are subject to the 20 meter low-pass filter, so both will have full sensitivity. Now you want to work a station heard on 40 meters (VFO B/sub). Since you need the 40 meter low-pass filter for transmit, you'd the controlling computer would need to swap VFOs (or you could do this manually by tapping A/B). 

* * *

Notes:

- If you had a separate receiving antenna usable on multiple bands, then the low-pass filter constraint goes away; either VFO could be on any band. You'd still need to swap VFOs to transmit on the VFO B band, then swap back.

- If you had a K4D, then each receiver would have its own set of bandpass filters, which may be helpful in high-signal conditions. They could also use different antennas. 

- It may even be possible to run WSJT on the K4 itself, though I can't put a date on this. Some porting required :)

73,
Wayne
N6KR



> On Aug 19, 2019, at 11:06 PM, Logan R Zintsmaster <lrahnz at garlic.com> wrote:
> 
> Here is a use case question.. 
> 
> The radio is connected to a single antenna.
> 
> VFO A is tuned to 14.074 MHz and VFO B is tuned to 14.080.  
> 
> An audio data stream from the VFO A frequency is "connected" to an instance
> of WSJT-X decoding FT8. 
> 
> A second, independent audio stream from the VFO B frequency is concurrently
> "connected" to a second instance of WSJT-X decoding FT4.  
> 
> Both instances of WSJT-X decode their respective audio streams,
> concurrently.
> 
> Starting a QSO in either instance of WSJT-X switches the transmitter to the
> appropriate VFO for the duration of the QSO.
> 
> The audio stream for the instance of WSJT-X not in the QSO is interrupted
> while the transmitter is operating.
> 
> 
> 
> Can a K4 support this use case or is a K4D required?
> 
> Can this use case be supported if each instance of WSJT-X is in a different
> band?
> 
> 
> 
> 73
> 
> Logan, KE7AZ
> 
> 
> 
> 
> 
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