[hpsdr] MOX and Duplex

[Joe Martin K5SO]

Hmm, perhaps RX1 is being set to “0 Hz” or at least some frequency other than the Tx frequency via the C&C bytes when in Tx mode in your code?

73, Joe K5SO

On Nov 22, 2014, at 12:21 PM, Bob Cowdery wrote:

> Hi Joe,
> 
> Thanks for the detailed explanation. I'm working out how best to do my
> transmit path so I first need to understand what the firmware is doing.
> I do plan to start looking at the firmware code but that will be a bit
> later on.
> 
> In my software at the moment all I do is link the RX1 and TX frequency
> if not duplex but otherwise the MOX and Duplex signals I generate set
> the appropriate bits in the CC,  and then for MOX, if there is more than
> one receiver I stop all except RX1. When I say stop I just stop the DSP
> processing and then start DSP processing for the TX. Similarly for MOX
> off I start DSP for any other receivers and stop for the TX. Apart from
> (un)linking the frequency and setting the CC bit I do nothing with
> Duplex in the PC code yet.
> 
> For testing I've just removed the antenna from Mercury and put a dummy
> load on Penny (I don't have PA or filters attached yet). Now I know I'm
> not doing this right yet as I'm deliberately leaving RX1 running
> regardless of the duplex setting in the firmware.
> 
> What I notice is that I can hear the signal in RX1 only if duplex is set
> in the firmware and I wondered what I was doing wrong as if the firmware
> does nothing to inhibit the signal I would expect to hear it regardless
> of duplex. It may be I have some frequency offset somewhere or I'm
> setting the wrong NCO bytes in one of the cases.
> 
> 73 Bob G3UKB


 1416685693.0