[hpsdr] WG: PowerSDR 2.2.3 (9/1/12)

[Joe Martin K5SO]

Hi Gerd, 

The SWR values are calculated within PowersSDR and are derived from the forward power (AIN1) and reverse power (AIN2) readings from the 100W directional coupler on the Alex Tx filter board.  If Alex is not selected in Setup > Hardware the forward power reading on the Tx meter reads the output power of Penny(Lane) (AIN5).     

If SWR is greater than 2:1 there will be a warning message displayed.  Further, there is external PA protection implemented in the code that reduces the output power to half if the measured SWR is greater than 2:1 and even further if the SWR is greater than 3:1.  

It is intended that these functions work only when Alex is selected and an external PA is used.  If you are using neither perhaps we need to examine the SWR metering and PA protection code further.  

It is unclear to me at the moment why you should be observing a constant 2.0:1 SWR reading if you are not using Alex or an external PA and do not have Alex selected in the setup menu.  Doug and I will take a look at the code to see if something is amiss there.  

Of course, it may be that since you are not using the current firmware versions for Pennylane (nor Mercury nor Ozy) the AINx signal paths may be incorrect in those versions for use with the SWR code and therefore some inappropriate signal is being used instead of valid AIN1, AIN2 signals for the SWR calculation in PowerSDR.   

73,  Joe K5SO


On Sep 10, 2012, at 5:01 AM, Gerd Loch wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hi Doug,
> 
> I am running PowerSDR 2.2.3 (9/1/12) with Ozy 2.1, Mercury-EU 3.1, Pennylane
> 1.6.
> When transmitting I get periodically the failure message "SWR too high" and
> the output power is oscillating. Switching TX-Meter to SWR does not show any
> SWR values. Only when switching Tx Meter to SWR in Settings, Transmit I get
> a constant indication of SWR 2.0:1.
> Where do Fdw and Rev power signals come from?
> 
> Gerd, DJ8AY
> 


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