Langstone Discussion Forum

Forum for discussion about the Langstone Microwave Transceiver that shares some features with the Portsdown. Wiki: https://wiki.microwavers.org.uk/Langstone_Project
radiogareth
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Re: Langstone Discussion Forum

Post by radiogareth » Sat Jun 12, 2021 7:17 pm

Looking ever upwards after successfully TXing 10GHz/5th harmonic DATV across the shack from my PD4/Langstone I took a chance and bought a couple of these boards from the well known Polish Ham/recycler.
Details here http://www.on6ll.be/on7fi/10GHz_CBNL/10GHz_CBNL.htm

Other people have clearly been at work on them and it would seem to be a perfect candidate to drive both TX and RX from the frequency agile Pluto and a handy LO of some sort.
I'm in the process of gathering as much info as possible before I power up the board, but it does look a really good way of accessing 10GHz and at 1W of power. There was also a similar board (TX strip only) that had a 3 watt final, driven in a similar fashion. The only info I have so far involved hacking off the front end and driving the pre-driver and PA directly.
Bit of a modern day 'Lisle Street'....
Gareth

radiogareth
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Re: Langstone Discussion Forum

Post by radiogareth » Wed Nov 17, 2021 8:43 am

In pursuit of getting the aforementioned board going on 10GHz NB (and DATV) I need a LO in the 2GHz region. I can use the same LO for RX and TX due to the flexibility of the Pluto RX/TX transverter modes.
At the moment I'm using a stand alone pushbutton programmed ADF4351 which works but needs programming each time I power it up.
Is there any capability for the Langstone (& Portsdown) to program one of these boards when its IN USE as a transverter? Since it was possible in the Portsdown 3 with the BATC Filter/Modulator board, I'd assume yes, but other than the signal generator software in PD4 I'm wondering if its a feasible addition?
Gareth

G8GKQ
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Re: Langstone Discussion Forum

Post by G8GKQ » Wed Nov 17, 2021 9:29 am

Hi Gareth

Although the Portsdown could do what you need, I would recommend a PIC-based solution instead. Far more reliable; I use it in most of my transverters. Full details here: https://wiki.batc.org.uk/ADF435x_PIC and the BATC shop sells PCBs.

Dave, G8GKQ

G4FRE
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Re: Langstone Discussion Forum

Post by G4FRE » Wed Nov 17, 2021 1:59 pm

Hi Gareth
I use the chinese AD4351 boards for a lot of my single frequency local oscillators, driven by a PIC. The modules I got had 2 rows of 6 pins header for the control signals so I couldnt use the BATC boards without much hacking so I got some PCBs made. You can see one at http://g4fre.com/Nactontv4m.htm

Dave
G4FRE

R1CAU
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Re: Langstone Discussion Forum

Post by R1CAU » Wed Nov 24, 2021 7:00 pm

Hello Colin.
Here once they asked a question about the expansion of the strip of the waterfall. You said that the power of the RPI is small and you shouldn't do it. In the above link, someone made a software modification and now the screen displays 192kHz. Today I measured the processor load on my RPI 4. The htop program shows the load about 50 ... 60 percent. I think the new RPI4 boards have enough resources for the 192/384kHz band. I noticed that there is a 512kHz stream from the Pluto (and Lime too?) in the receiving resources, which you decimate to 48k. I think that the restriction in the 48k band was relevant for RPI3, and for new RPI4, these restrictions are not relevant.
Hopefully there will be a wider waterfall streak in future Langston / Langston2 builds?

192kHz mod:
https://youtu.be/e1IaYid4d-0

Unfortunately, the author of the video did not share his modification. The wider bandwidth allows you to search for correspondents more conveniently. This is relevant on sparsely populated microwave bands and is especially important during VHF cantests.

g4eml
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Re: Langstone Discussion Forum

Post by g4eml » Wed Nov 24, 2021 7:45 pm

Langstone has always been designed for the Pi4. Never for the Pi3.

I have done several experiments to increase the FFT width and it can be done, but I have never been happy with the result. The amount of processor time used rises rapidly with even small increases and overheating of the Pi quickly becomes a problem.

Colin.

R1CAU
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Re: Langstone Discussion Forum

Post by R1CAU » Thu Nov 25, 2021 3:31 am

Maybe, as an experiment, make it possible to select the 48/96/192kHz band?
A radiator is placed against overheating.

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