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

[Logan R Zintsmaster]

Thanks for the explanation. The band pass filters add an interesting consideration to multi-band use. 

Sent from my iPhone

> On Aug 20, 2019, at 8:27 AM, Wayne Burdick <n6kr at elecraft.com> wrote:
> 
> 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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>