Langstone Update

Forum for discussion about the Langstone Microwave Transceiver that shares some features with the Portsdown. Wiki: https://wiki.microwavers.org.uk/Langstone_Project
g4eml
Posts: 206
Joined: Thu Apr 26, 2018 9:36 am

Re: Langstone Update

Post by g4eml » Fri May 22, 2020 8:47 pm

There are occasional clicks on receive which I think are the same problem in the opposite direction. The Audio is occasionally running out of data. Not too much of a problem on RX.

I will see if there is a way to flush the TX buffers in between transmissions. Then the problem would only occur if you have very long overs.

Colin.

G4GUO
Posts: 655
Joined: Tue Feb 16, 2010 12:51 pm

Re: Langstone Update

Post by G4GUO » Fri May 22, 2020 8:59 pm

I am going to have the same problem with the SDR I have started to code.
I did look at a cheap sound dongle based on the CM108 USB chipset that has an external 12 MHz oscillator to generate all the internal sample rates.

Now I have to find a way of taking the 40 MHz oscillator on the Pluto and use it as a reference to generate a 12 MHz clock. All the
cheap clock generator chips on eBay need 25 MHz.

- Charles

g0mjw
Posts: 1135
Joined: Sat Sep 20, 2014 9:15 am

Re: Langstone Update

Post by g0mjw » Fri May 22, 2020 9:08 pm

Why not feed it with 10 MHz and adjust for the sample rate error?

G4GUO
Posts: 655
Joined: Tue Feb 16, 2010 12:51 pm

Re: Langstone Update

Post by G4GUO » Fri May 22, 2020 9:16 pm

12 (x4) MHz is also use for the USB2 interface and it would probably break that bit.

- Charles

M0DTS
Posts: 426
Joined: Sun Feb 24, 2008 9:03 pm

Re: Langstone Update

Post by M0DTS » Sat May 23, 2020 9:04 am

The Si5351 clock chips may work Charles, I've used them with 10MHz input before and worked ok.
40MHz may also work...

edit - just tested one and it does indeed work, generated 12MHz from 40MHz ref input.

Rob

G4GUO
Posts: 655
Joined: Tue Feb 16, 2010 12:51 pm

Re: Langstone Update

Post by G4GUO » Sat May 23, 2020 9:39 am

Hi Rob,

I knew someone would have a solution. What varient of that chip are you using?
The ones I have are designed to use a 25/27 MHz Xtal. I assume you removed the Xtal,
grounded one side via a capacitor and then fed the reference signal into the other pin?

Hopefully I will get the CM108 next week to try the idea out.

- Charles

M0DTS
Posts: 426
Joined: Sun Feb 24, 2008 9:03 pm

Re: Langstone Update

Post by M0DTS » Sat May 23, 2020 10:52 am

Yes mine was a 25MHz version, that's exactly what i did.

Rob

G4FKK
Posts: 44
Joined: Sun May 05, 2019 12:15 pm

Re: Langstone Update

Post by G4FKK » Sun May 24, 2020 2:02 pm

Hi Colin,

A bit more user feedback:

I've found my stubby fingers and careless operating means that sometimes I touch the DOTS button instead of the PTT button when going from transmit to receive. When this happens and I press DOTS again, the receiver locks up and requires a re-boot. Pressing PTT followed by DOTS seems to be ok.

I've also noticed that Band 2 (144MHz in my case), doesn't remember the settings (last frequency and Txvtr Tx/Rx settings), after switching to Portsdown and then back to Langstone via Portsdown Menu2. Band 1 and band 3 (70MHz and 432 MHz respectively here), seems ok in this regard. I haven't tried any of the other bands yet.

All understood re. transmit latency and mic gain/response.

I had an excellent Langstone to Langstone QSO with RadioGareth on 4m earlier today :)

73, Martin - G4FKK

g4eml
Posts: 206
Joined: Thu Apr 26, 2018 9:36 am

Re: Langstone Update

Post by g4eml » Sun May 24, 2020 3:11 pm

Thanks for the feedback Martin.

I think I know what might be causing the second band problem. It is actually band 1 in the software. The old software used bands 0 to 9 but now I have added two more it uses 0 to 11. I suspect the search for BAND1 is also finding BAND10 and BAND11. I will fix it later.

I will also have a look at the dots problem.

73

Colin.

g4eml
Posts: 206
Joined: Thu Apr 26, 2018 9:36 am

Re: Langstone Update

Post by g4eml » Sun May 24, 2020 9:36 pm

New update 24/05/20

Fix for second band not saving its frequency.

Fix for lockup when using DOTS.

Note that the fix for the frequency saving will result in your Langstone.config file being reset to defaults even if you have saved it.
Sorry, hopefully that is the last time that will happen.

Colin G4EML

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