Langstone Update 28/05/20

[g4eml]

Mike,

The current arrangement was trying to be compatible with the Portsdown band selection arrangement which uses external decoders.

Colin.

[g0mjw]

I know but that doesn't mean we can't add another 4....

[G8GKQ]

Mike

I can't see why you don't use the BATC 3-line to 8 line PCB (known as the 8-band decoder). It includes the opto-isolators and is designed for the job.

I know from experience that the less variation in hardware design that needs to be supported by community software, the better.

Dave, G8GKQ

[g0mjw]

Hi Dave,

Because I want to control 8 things but poly-phonically, so you might want to operate more than one relay at a time, e.g. with QO100 you might want to select 2.4 GHz uplink and perhaps 3cm downlink.

[G8GKQ]

But the rest of the design does not support simulataneous transmit and receive....? Unless you have a clever software modification?

Keep it simple!

Dave

[g4eml]

Actually Langstone does allow simultaneous TX and RX when the Tx and Rx offsets are set to different non zero values. (SAT Mode). A button labels ‘MONI’ will appear which unmutes the receiver during transmit. It does put a lot of extra load on the CPU though.

The current 4 band bits can be used directly with relays to support 4 transverters. The bit pattern for each band is configurable from the setup menu.

Yes, it could be increased to 8 bits but that is probably not something most would need so would be better implemented as an option.

Colin.

[g0mjw]

But the rest of the design does not support simulataneous transmit and receive....? Unless you have a clever software modification?

Keep it simple!

Dave

I thought it did. Gnuradio certainly does and for QO100 you should not operate simplex. But even if not sometimes there are more than one thing to control per band so having the ability seems sensible.

Mike

[G8GKQ]

Thanks Colin - even more capability than I realised!

Mike - the other option is that you modify the PIC code in the 8-band switch. It's all on Github, and the mapping for band select binary to the 8 outputs is here: https://github.com/BritishAmateurTelevi ... e.asm#L412

Dave

[G4FRE]

The modified PIC option was the route I chose, especially as, not using the LO filter I had some spare pins to play with

Dave
G4FRE

[g0mjw]

Thanks Colin - even more capability than I realised!

Mike - the other option is that you modify the PIC code in the 8-band switch. It's all on Github, and the mapping for band select binary to the 8 outputs is here: https://github.com/BritishAmateurTelevi ... e.asm#L412

Dave

PIC code? There is no PIC involved. This is not the RF switch. Its the common ebay 8 relays with opto isolators board.