band switching

Discussion about this major DATV Project. See https://wiki.batc.org.uk/The_Portsdown_Transmitter
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moonbouncer
Posts: 9
Joined: Sun Feb 06, 2022 1:42 pm

band switching

Post by moonbouncer » Fri Feb 20, 2026 12:39 pm

Hi all,

In my system the GPIO outputs for band switching are not the same for Langstone and Portsdown.
On 4m, 2m 70 cm and 23 the GPIO outputs on the pins GPIO 7, 32 and 35 are the same. But on the higher bands (13cm and up) the GPIO output on Portsdown is the same as on 23 cm (ie. 0,1,1), while on the Langstone transceiver they change on every higher band. E.g. on 13 cm the Langstone output is 1,0,0 and on Portsdown it is 0,1,1 (the same as on 23cm).

How can I solve this problem on Portsdown? I use the GPIO outputs for band switching.

73's de Ruud PA7RP

radiogareth
Posts: 1486
Joined: Wed Jan 06, 2016 9:46 am

Re: band switching

Post by radiogareth » Fri Feb 20, 2026 2:25 pm

I'm fairy sure the Langstone band bits can be selected.....SET then scroll through to Tx and then RX band bits...
Gareth

g0mjw
Posts: 2744
Joined: Sat Sep 20, 2014 9:15 am

Re: band switching

Post by g0mjw » Fri Feb 20, 2026 4:38 pm

You can more easily set them on the Langstone, so set them to be the same as the Portsdown. Problem solved.

Mike

moonbouncer
Posts: 9
Joined: Sun Feb 06, 2022 1:42 pm

Re: band switching

Post by moonbouncer » Sun Feb 22, 2026 11:01 am

That doesn't solve the problem. The problem is that on portsdown there is no difference on the status of gpio's 4, 12 and 19 for all bands above 1 Ghz.
So if I choose 23, 13 or 9 cm...the output on these GPIO's stays the same.

Pa3fbx
Posts: 244
Joined: Fri Oct 16, 2020 1:08 pm

Re: band switching

Post by Pa3fbx » Sun Feb 22, 2026 11:27 am

Not on my system...
And also in Portsdown the GPIO selection can be changed in band settings...

Benno

g0mjw
Posts: 2744
Joined: Sat Sep 20, 2014 9:15 am

Re: band switching

Post by g0mjw » Sun Feb 22, 2026 1:25 pm

Perhaps not read this ?

https://wiki.batc.org.uk/Portsdown_4_GPIO_Connections -seems to be missing D3? There should be 4 band bits, not 3. Well actually 5 but who needs 5.

Mike

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