Portsdown 4 / Langstone Rx selection

[g4saq]

When using PD4 the receiver is the Minitiouner but for Langstone the receiver is the Pluto. Is there a means of sensing which Rx is required so that a relay can be used to change the Rx path from Minitiouner to Pluto? (a GPIO pin) I cannot see that this is available - sorry if I've missed it! Regards, Russ.

[G8GKQ]

Hi Russ

Yes there is, but it is well hidden!

If you are not using GPIO physical pin 21 for band switching (which some builders do), it is set to 0v for Portsdown and 3.3v for Langstone. It is briefly mentioned here: https://wiki.batc.org.uk/Portsdown_4_GPIO_Connections.

Dave

[g4saq]

Thanks Dave. Yes, it was hiding in plain sight on the list of GPIO connections - sorry! I am using the 8 band decoder and switch so pin 21 (D7) will be available to me. Perfect.
BTW I've just seen your post regarding the facility to pre-select boot-up mode. Great idea, thanks. (I had been wondering whether a GPIO could be used to select PD4/Landstone at boot up)
Regards, Russ.

[radiogareth]

And I THINK (because there is one in my first PD4) you can add a IO extender that only works with the Langstone. That would open up all sorts of extra stuff.
Sorry it was 18+ months ago and I have forgotten where, fairly sure the Langstone Wiki will have it.
BW

Gareth

[g4saq]

Thank you, Gareth. I'll take a look at that. Russ

[radiogareth]

Here it is....https://wiki.microwavers.org.uk/Langsto ... c_expander
Gareth

[g4saq]

Thanks Gareth. Russ

[g4saq]

I am having a problem using GPIO 9 (pin 21 on the RPi and D7 on J3 of the breakout board). My understanding is that it is supposed to output 3.3V when in Langstone mode and 0V in Portsdown mode. I have tried connecting it to the base of a BC547 via 10K to switch a 12V SMA relay (yes, with back EMF diode!). It didn't work. So, I measured the voltage on D7 as 13mV in Portsdown and 17mV in Langstone. Hmmm, something not right here. Please can anyone advise? Thanks, Russ.

[g4saq]

Sorry, should have said Buster 202212210. Russ.

[g4eml]

Pin21 is not necessarily high when running Langstone.
It is band select bit 7 and can be set high or low as you require from the Langstone settings menu. It is also independently set for Tx and for Rx.

So if you want it to be always high you would need to set band bit 7 high for both Tx and Rx on every band.


Colin G4EML.