A couple of years ago I requested that PD4/ Langstone should be altered so that a GPIO pin was set high when Langstone was selected and low when PD4 was selected. I wanted to operate a relay which would route the receive chain to either the Pluto (for Langstone) or MiniTiouner (for PD4), as required.
I can’t remember whether the requested mod was already in place or whether work was done to include it! Anyway, I was advised to use GPIO 21 and to set the Langstone Rx bandbits 7 (for each band) to activate the relay. This solution has worked very well indeed, providing the automatic selection that I required.
My present request is that the code should be modified to set GPIO 21 high when Band Viewer is selected and to set GPIO 21 low again when Band Viewer exits. This will automatically switch my relay and route the Rx chain to the Pluto Rx port, as required for this valuable function. (This will need to be done for both of the Band Viewer options).
Very many thanks & 73.
Russ, G4SAQ.
Portsdown 4 modification request
Re: Portsdown 4 modification request
ISSUE RESOLVED - I'm posting this note in case others are wondering if the modification has been made. Yes! Dave, G4GKQ, kindly modified the PD4 code a while back so that GPIO 21 goes high when Band Viewer is selected. This is very useful as it facilitates operation of a relay to switch the Rx chain between a MiniTiouner/ Pico Tuner and a Pluto SDR.
If, like me, the modification does not appear to work for you, the solution is to re-build the PD4 SD card with the latest image. Unfortunately, a simple update operation will not reinstate the missing file.
Many thanks to G8GKQ - again!
73, Russ, G4SAQ.
If, like me, the modification does not appear to work for you, the solution is to re-build the PD4 SD card with the latest image. Unfortunately, a simple update operation will not reinstate the missing file.
Many thanks to G8GKQ - again!
73, Russ, G4SAQ.
Re: Portsdown 4 modification request
Hello Russ
Have the same problem , read the post:
Help PORTSDOWN /LANGSTONE info pin 21
by HB9IAM » Wed Jul 09, 2025 2:29 pm
viewtopic.php?f=103&t=9183
Best 73 Pierre HB9IAM
Have the same problem , read the post:
Help PORTSDOWN /LANGSTONE info pin 21
by HB9IAM » Wed Jul 09, 2025 2:29 pm
viewtopic.php?f=103&t=9183
Best 73 Pierre HB9IAM
Re: Portsdown 4 modification request
Hi Pierre,
I think you might have misunderstood the purpose of GPIO 21. It is an output pin which can be used to drive a relay to switch the receive circuits between a DATV tuner and an SDR Rx input. If you are using Portsdown DATV you want the receive chain to connect to a DATV tuner (the Minitiouner or Pico Tuner). In Portsdown DATV mode, GPIO 21 is ALWAYS low. However, if you are using Langstone, you will want to direct the receive chain to your SDR Rx port. In Langstone, you can make GPIO 21 go high by altering the Rx Band Bits (in the Langstone 'Set' menu). You have to set bit 7 to '1' and you must do this for every band that you want to use. Once you have done this, the changes will stay in memory. After you have done this, the change between DATV tuner and SDR Rx port is automantic. Now, you mentioned Band Viewer. Dave , G8GKQ, has amended the code so that selecting Band Viwer automatically sets GPIO 21 high, thereby switching the relay to the SDR Rx port. Don't forget to use an NPN driver for your relay as the GPIO pins are at 3.3V and low current. Finally I should say that GPIO 21 has nothing to do with delaying transmissions. I hope that helps you.
73, Russ, G4SAQ
I think you might have misunderstood the purpose of GPIO 21. It is an output pin which can be used to drive a relay to switch the receive circuits between a DATV tuner and an SDR Rx input. If you are using Portsdown DATV you want the receive chain to connect to a DATV tuner (the Minitiouner or Pico Tuner). In Portsdown DATV mode, GPIO 21 is ALWAYS low. However, if you are using Langstone, you will want to direct the receive chain to your SDR Rx port. In Langstone, you can make GPIO 21 go high by altering the Rx Band Bits (in the Langstone 'Set' menu). You have to set bit 7 to '1' and you must do this for every band that you want to use. Once you have done this, the changes will stay in memory. After you have done this, the change between DATV tuner and SDR Rx port is automantic. Now, you mentioned Band Viewer. Dave , G8GKQ, has amended the code so that selecting Band Viwer automatically sets GPIO 21 high, thereby switching the relay to the SDR Rx port. Don't forget to use an NPN driver for your relay as the GPIO pins are at 3.3V and low current. Finally I should say that GPIO 21 has nothing to do with delaying transmissions. I hope that helps you.
73, Russ, G4SAQ