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

Re: Langstone Discussion Forum

Post by g0mjw » Fri Jul 31, 2020 7:24 am

There is a shortcut - if you are confident - to setting offsets etc. That is to stop the program and edit the Langstone config file directly where these values are stored. I won't say how as if you need to ask it's likely you shouldn't attempt it. If you do, make a backup.

Mike

DL5BCA
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Joined: Tue Jun 30, 2020 11:59 am

Re: Langstone Discussion Forum

Post by DL5BCA » Fri Jul 31, 2020 7:33 am

Hello Mike,

thanks for your note.

Now i found, that i can use the mouse buttons.. So i can change the position of the cursor.


I just have a repeater in 500meter distance. I make my first attempts with the repeater in FM modulation, without LNB or amplifier.
I'm testing 2 headsets and a table microphone. All 3 microphones sound very muffled ...

But that is crying at high levels.

73 Thomas DL5BCA

g0mjw
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Re: Langstone Discussion Forum

Post by g0mjw » Fri Jul 31, 2020 7:47 am

I did wonder about the mouse comment.

In my case all the relays are inverted and swapping them all from 00000000 to 11111111 on all bands was a little tedious but quick fix to change all to 255 and then select the required pattern as necessary. At the moment that's none as I am not driving anything external yet, but I will be.

I think I have got to the bottom of my audio amplifier noise. Same on Portsdown. It's ground loop between audio the DC supply so some filtering is needed.

I attached it to QO-100 last night. Set the offsets (in the file) and was rewarded by an empty transponder but the beacons were there. It would be better if the spectrum graph was a bit taller and the waterfall a bit shorter, I will figure out that later. I also need XIT because the offset between RX and TX is different and varies a few 10s of Hz as the Pluto warms up. It has a replacement TCXO but it's not perfect. For QO-100 RX is 990 MHz and TX 2.4 GHz so to be right on frequency you need to adjust RIT and XIT in approximately a 10:24 ratio when compensating for this drift.

Mike

DL5BCA
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Joined: Tue Jun 30, 2020 11:59 am

Re: Langstone Discussion Forum

Post by DL5BCA » Fri Jul 31, 2020 9:26 am

Hi Mike,

I don't have anything attached to it at the moment. For the QO100 I use the SDR console, which allows the connection to the beacon.

I am interested in using the Langstone TRX in higher bands. You can receive and send the Pluto, LNAs and PAs directly behind a mesh disk and so with very little loss.
With other software and possibly manual switching, you could also do DATV with it ...

If someone writes the appropriate software, you could even do analog ATV .. That should work too ...

But everything one after the other ...

i live in the very flat area in the north of germany. To the north, to the west, the route is sure to be towards the Netherlands, Belgium, France and Great Britain.

73 Tommi DL5BCA

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

Re: Langstone Discussion Forum

Post by g4eml » Fri Jul 31, 2020 10:29 am

As you have found, when setting the offsets the left and right mouse buttons select the digit to be adjusted in the same way as for normal tuning.

DL5BCA
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Joined: Tue Jun 30, 2020 11:59 am

Re: Langstone Discussion Forum

Post by DL5BCA » Fri Jul 31, 2020 11:43 am

Yes, whoever reads instructions has a clear advantage.

Thank for your effort, Collin.

73 Thomas DL5BCA

g4eml
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Re: Langstone Discussion Forum

Post by g4eml » Fri Jul 31, 2020 12:27 pm

Hi Thomas,

The original Langstone was not intended for use with repeaters, the Tx and RX offsets were intended for use with transverters.

I does appear that people are using this for more than was originally intended. So repeater features might be worth adding.

Therefore I plan to add a separate repeater shift parameter for each band. I will also add a Duplex/Simplex button to the menu. As a side effect this would also allow the repeater shift to work when using transverters. (10GHz repeaters?)

Of course to use repeaters would probably also need CTCSS and 1750Hz. That might have to wait a while!

Your comments about the FM audio sounding
muffled might be down to the GNU Radio FM modulator. I suspect the default pre-emphasis may not be correct. It needs some experimenting.


Colin

DL5BCA
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Re: Langstone Discussion Forum

Post by DL5BCA » Fri Jul 31, 2020 1:09 pm

Dear Collin,

isn't it already the case that different offsets can be set for each band?

I would also like it if TX shows the TX frequency (RX frequency - + offset).

I also think that many users use the Langstone TRX in FM.

Buttons for RX and TX offset (on / off) would be great.

So far I have only programmed Python on the GUI. Without graphics, only states recorded and then events triggered.
Is it possible to do the Langstone on the GUI?

73 Thomas DL5BCA

g4eml
Posts: 223
Joined: Thu Apr 26, 2018 9:36 am

Re: Langstone Discussion Forum

Post by g4eml » Fri Jul 31, 2020 4:10 pm

Yes, offsets are for each band but they are designed for transverters not for repeaters. I don’t want to change this.

New Repeater shifts will be just for repeaters with on off selection.

Actual Tx frequency will be displayed when using these.

I do not understand your question about the GUI.

Colin.

g4eml
Posts: 223
Joined: Thu Apr 26, 2018 9:36 am

Re: Langstone Discussion Forum

Post by g4eml » Sat Aug 01, 2020 12:58 pm

Update released.

Now includes new setting for each band "Repeater Shift". Use this instead of Tx Offset.
Tx Offset remains for use with Transverters.

When set to FM mode with a Repeater Shift that is not zero a new button will appear on the bottom row. "DUP"
Pressing this button turns the repeater shift on and off. A "DUP" indication appears above the frequency display.

When transmitting the frequency display will change to the Receive Frequency + Repeater Shift.
The DUP button will change to read "1750". Pressing this button while transmitting will send a 500ms burst of 1750Hz.


The Langstone project was (and is) intended to encourage the use of the microwave bands. Support for other uses such as the lower bands with repeaters will always be limited.

Colin G4EML

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