Help PORTSDOWN /LANGSTONE info pin 21

Discussion about this major DATV Project. See https://wiki.batc.org.uk/The_Portsdown_Transmitter
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HB9IAM
Posts: 16
Joined: Thu Nov 24, 2011 12:19 am

Help PORTSDOWN /LANGSTONE info pin 21

Post by HB9IAM » Wed Jul 09, 2025 2:29 pm

To avoid the 3 second TX/RX delay on LANGSTONE, need to sitch off the MiniTiouner.
The Portsdown 4 GPIO Connections Table show that Pin 21 is LOW for Porstdown, HIGH for Langtone.
One my two Portdown-Langstone units, i get no voltage change ?
Why ?

Pierre HB9IAM

g4eml
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Joined: Thu Apr 26, 2018 9:36 am

Re: Help PORTSDOWN /LANGSTONE info pin 21

Post by g4eml » Wed Jul 09, 2025 4:09 pm

No idea why the minitiouner would case that. It must be causing a problem on the USB.

Pin 21 is not used on Portsdown. On Langstone it is the most significant bit (D7) of the user programmable band bits. I don't know where the comment about being high for Langstone came from but it is not correct.

Colin G4EML

HB9IAM
Posts: 16
Joined: Thu Nov 24, 2011 12:19 am

Re: Help PORTSDOWN /LANGSTONE info pin 21

Post by HB9IAM » Wed Jul 09, 2025 4:10 pm

Raspberry Pi4
Portsdown 20241290
Langstone V2 use Pluto

HB9IAM
Posts: 16
Joined: Thu Nov 24, 2011 12:19 am

Re: Help PORTSDOWN /LANGSTONE info pin 21

Post by HB9IAM » Wed Jul 09, 2025 9:39 pm

Hi Colin
The comment is from the Portsdown GPIO connections table
GPIO pin 21
GPIO pin 21
Portsdown 4 GPIO Connection pin 21.PNG (18.36 KiB) Viewed 232 times
I try to Pull Up the pin 21 - no sucess

I have High on pin 21 for Porstdown, but just in Band Viever mode ...

Its a anoter possibility to get a indication of the mode in service ?
Pierre HB9IAM

g4eml
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Joined: Thu Apr 26, 2018 9:36 am

Re: Help PORTSDOWN /LANGSTONE info pin 21

Post by g4eml » Wed Jul 09, 2025 11:51 pm

That comment is wrong. I don't know who wrote it.

If you want pin 21 to be high when running Langstone you need to set Rx band bits and Tx band bits to 1xxxxxxx for every band. Do this in Langstone using the settings menu.

Langstone band bits are 8 outputs that can be set to whatever the user wants. Each band has it's own values for Tx and Rx.

Colin.

G8GKQ
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Re: Help PORTSDOWN /LANGSTONE info pin 21

Post by G8GKQ » Thu Jul 10, 2025 7:23 am

Thanks Colin for the correct answer on this one. I couldn't remember the exact details and had not had time to test it.

The reason that this pin also goes high with BandViewer is to enable the receive aerial to be switched from the MiniTiouner to the SDR when using BandViewer (feature requested by PA3FBX).

Dave, G8GKQ

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