BATC Forum

Hello all,
I have built a Langstone transceiver last year and I intend to use it with WSJT-X in future.
In order to compensate for (moon-) Doppler it would be necessary to have CAT-control, so I would like to support the question by F1HDI some months ago.
I have tried to load the Lang_RX.grc flow diagram in GNU Radio Companion, version 3.8, but it shows missing blocks. In what version of GRC was the flow diagram made?
And I have tried to do noise figure measurements on the Langstone but the action of the AGC makes this impossible. Would it be possible to make a version with an extra knob or setting to disable the AGC3 block and circumvent it with a fixed gain block?

73, Jos, PA0JOZ

I have no plans at the moment to add CAT control. Maybe in the future, but it is not a simple thing to add.

The GRC files were created using Version 3.7.13.4.

Colin G4EML

In the Langstone menu structure you can turn off AUTO and select any fixed gain you like. Rx Gain then use the rotary control to choose.
Gareth

Gareth, I think Jos is referring to the audio AGC which is part of the GNU radio flowgraph and can't be turned off.
This is separate to the RF Gain you mentioned.

Colin.

Hello Colin and Gareth,

Thanks for the answers. Indeed, I referred to the AGC3 block in the RX flow diagram. I think I will install the version of GRC mentioned by Colin on a separate PC and try to amend the flow diagram myself with a bypass to the AGC block. After that I'll have to figure out how to add a button to the GUI to control the bypass.
As for the CAT-control: I have implemented CAT from scratch in my homemade VHF/UHF transceivers but that was done with PIC controllers and programmed in assembly. Maybe I can gather enough courage to give it a try on the Raspberry Pi.
If something useful comes from my efforts I will inform you.

73, Jos, PA0JOZ