Searching for a few answers regarding Lime

The place to discuss the use of the LimeSDR Mini for amateur TV applications
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G8JAN
Posts: 47
Joined: Mon Feb 25, 2008 7:12 pm

Searching for a few answers regarding Lime

Post by G8JAN » Sat Oct 19, 2019 11:13 am

The only item of digital equipment I have in my shack is a Sat RX plus a pre amp for 23 cms. Sadly my old brain wont take in digital information published in the BATC mag and elsewhere so in that respect I am very much a digital ATV beginner despite being into Analogue ATV since the mid 1970's!

Basically what I want is to be able to see digital transmissions below 23 cms. So the first of my questions is:

Can I use the Lime barefoot simply plugged into a desktop or a laptop computer with the necessary software or is there any other receiving device I can use? I have a SDR play module and several dongles.

Most of the digital equipment I've tried to get my head around seems to require a Pi board. Obviously because it's useful for all kinds of experiments when developing hardware. But why can't a half decent laptop be used? After all they are quite powerful have several USB inputs. Audio boards and touch screens. So for a casual user of digital who like me is not interested in experimenting with digital processing but would like to see whats happening is there an easier and cheaper way?

I very much like cheap in my Amateur radio so any advice on how to keep down costs while receiving video on the lower bands would be appreciated. Looking at the cost of a Lime module only is in practice more than I want to pay.

Finally there are several local ATVers like me who would like to have a look on the lower bands and at digital transmissions in general. What we really need is a very simple article written as a guide to taking first steps in receiving digital, keeping jargon to a minimum and costs low.
Can anyone help?

Pete
G8JAN

g8gtz
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Joined: Wed Apr 07, 2010 6:26 pm

Re: Searching for a few answers regarding Lime

Post by g8gtz » Sat Oct 19, 2019 11:55 am

Hi Pete,

I'll have a go at keeping it simple!

Receiving DATV:


The only real show in town and the most flexible, is the PC based MiniTiouner system with a USB tuner card. The reason for this is that it tunes from 143 MHz to 2450 MHz so covers all the bands from 146 > 13cms and with a standard LNB can be used to receive Oscar 100 signals. It also can recieve all the Symbol Rates (SR) or bandwidths from 33Ks (the lowest RB-TV you will find) right up to 27,500 as used on Freeview etc.

The system consists of the USB tuner card hardware which you build (no Surface Mount!) - the 4 hard to get components are from the BATC shop and the software is free to download - total cost = ~£80 depending upon the case you use.

You will then need the normal filters / pre-amps annd / or LNB depending on the band you want to receive but it will be all you will ever need!

See https://wiki.batc.org.uk/MiniTioune for more details.

Yes, there are are a couple of Set Top Boxes that will receive some reduced bandwidth signals but you will need freq converters etc. There is also a PC software program called SDRAngel which you can use with the cheap £10 RTL dongle. In my opinon both of these options require a lot of faffing about and you cannot quarantee results.

DATV transmit

I would suggest the BATC Portsdown system is the way go. Yes it is Raspberry Pi based but you can buy a pre-programmed SD card from BATC so there is no programming or computer wizzardry at all. This plus a touch screen and a LimeSDR Mini, which simply plugs in to the Rpi USB socket, will give you a simple to use touch screen DATV transmit system.

This basic system will cost ~ £250 ( less than a dual band FM rig!) and give you a full blown DATV transmit system from 50MHz up to 3.4GHz with good picture quality over all the common symbol rates. Again you will need filters and amplifiers for the band of your choice....

https://wiki.batc.org.uk/Portsdown_2019

A slight confusion now is that you can plug the MiniTiouner USB tuner hardware in to the Portsdown system and it will display the pictures, thereby becoming a full DATV transceiver and replacing the need for a PC.

I think that is the basic story - hope it makes sense - KISS!! We did try and put some beginners guides on the wiki but things move very fast and they are soon out of date - just need some volounteers to update them!

Any questions - just ask.

73

Noel - G8GTZ

G8JAN
Posts: 47
Joined: Mon Feb 25, 2008 7:12 pm

Re: Searching for a few answers regarding Lime

Post by G8JAN » Sun Oct 20, 2019 10:15 am

Many thanks for that Noel as a Digital newbie I see lots if people discussing digital online and I see articles in the BATC mag but I see very little printed or posted to explain the absolute basics for us beginners. I think we have been overlooked by the speed of digital working and the hardware required.Pete G4 NJJ as you know is very knowledgeable in electronics but even he is struggling to take it all in as are a couple of other ATVers locally. People like myself with no electronic background are certainly floundering. Maybe it's time to consider putting some basic information in the magazine to help not only us existing members but those licenced Amateurs who want to know more about ATV.

As an aside Pete has offered to let me try his MiniTiuner so that would be a start. In the meantime we are still struggling to get a 5 Ghz link between us but we are getting there over an obstructed path. It took 18 months to get a 10GHZ link to his old QTH So we are triers here in Norfolkshire! :D :D

Pete
G8JAN

AdrianH
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Joined: Thu Jul 18, 2019 2:46 pm

Re: Searching for a few answers regarding Lime

Post by AdrianH » Sun Oct 20, 2019 2:26 pm

I have a question here to add if I may. Pete asked about a PC based system to drive something like the Lime SDR. You suggested a raspberry PI, which unless I am wrong is a small PC running Linux, is there not a version of this software that will run on a Linux desktop or laptop?

Adrian

g8gtz
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Joined: Wed Apr 07, 2010 6:26 pm

Re: Searching for a few answers regarding Lime

Post by g8gtz » Sun Oct 20, 2019 3:01 pm

@ Pete,

I have just checked the wiki and there is a getting started page: https://wiki.batc.org.uk/Getting_Started

Unfortunately much of the info is out of date including this how to receive DATV from CQ-TV in Spring 2016 (only 3.5 years ago) we really do need everyone in the ATV community to help keep this sort of information up todate https://wiki.batc.org.uk/images/a/af/Ge ... eption.pdf

Very happy to publish a series of beginners guides in CQ-TV but who is going to write them??

@ Adrian

The official BATC Portsdown release is designed to operate with some very speciifc hardware and it does that very well. However the code is available on the BATC github and avaiable for anyone to download and experiment.

Not being a Linux user I'm not sure if there is any other DATV Linux software....

73
Noel - G8GTZ

AdrianH
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Joined: Thu Jul 18, 2019 2:46 pm

Re: Searching for a few answers regarding Lime

Post by AdrianH » Sun Oct 20, 2019 4:18 pm

Thank you Pete i will have a look, I am very poor at software, but having a look will not hurt.

Adroan

G8GKQ
Site Admin
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Re: Searching for a few answers regarding Lime

Post by G8GKQ » Sun Oct 20, 2019 4:53 pm

Hi

Here are my responses to the questions floating around in this thread.

The best beginner's receive digital receive sytem is a MiniTiouner and a Windows 10 PC/laptop.

The best beginner's transmit sytem is a Portsdown sytem comprising a Raspberry Pi 3B+, Pi Camera, USB Microphone dongle, 7 inch touchscreen, LimeSDR Mini and a BATC Portsdown SD Card. Just connect the parts together (no soldering or software tinkering required) and you can generate a few milliwatts of digital TV on any band from 50 MHz to 3.4 GHz.

Please read my "Portsdown Made Simple" article on pages 15 and 16 of CQ-TV 264. It was written for you!

You could connect the MiniTiouner to the Portsdown to receive, but I would suggest learning about MiniTiouner first.

[Having written all this, I note that Noel said the same!]

The Raspberry Pi has a very different CPU architecture to a PC, so all the Portsdown code would need to be recompiled/rewritten to run on a Linux PC. The LongMynd software (used to receive DATV with the MiniTiouner on the Portsdown) can be recompiled relatively easily, but would then need to be controlled from the command line as the touchscreen interface is Raspberry Pi-specific. It is not practical to rewrite the Portsdown transmitting software for a Linux PC, although some components of it can be transferred.

Dave, G8GKQ

G8PEF
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Joined: Mon Oct 30, 2017 6:42 pm

Re: Searching for a few answers regarding Lime

Post by G8PEF » Sun Oct 20, 2019 10:59 pm

g8gtz wrote:
Sat Oct 19, 2019 11:55 am
... We did try and put some beginners guides on the wiki but things move very fast and they are soon out of date - just need some volounteers to update them!...
Noel - I'm always happy to edit wiki pages (and I do occasionally try to improve pages, and make styles more consistent); the problem I have is not necessarily knowing which ones need attention, and often not having the technical knowledge on a particular topic to make/amend pages...
Is there a 'todo list' for updates required? If that were available to peruse, then I (and others) might find something that we're comfortable with tackling.

For anyone thinking that they may like to help, but are afraid that wiki editing is difficult, I can assure you that basic editing of the text is fairly straightforward, so please, if you've seen a typo, or if you can add a useful snippet, or can improve the existing text, please get stuck in!

G8JAN
Posts: 47
Joined: Mon Feb 25, 2008 7:12 pm

Re: Searching for a few answers regarding Lime

Post by G8JAN » Mon Oct 21, 2019 7:17 am

Firstly I must apologize for asking my questions on the wrong thread sorry about that. But thanks to all who have replied. I will take on board the information and do some more reading. At present I'm not too concerned about digital transmission it's the RX side which I want to get started on mainly to see whats going on further afield. To that end it's digital on the bands below 24 cms which I'm interested it. There is if course the satellite but it's years since I took down my sat analogue DX system. As I mentioned, Pete G4NJJ has offered me the use of his Minitiouner which seems to be a good way of starting.

Thanks again.

Pete
G8JAN

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