Raspberry Pi 2

The place for discussion about the RPi add-on RB-TV modulator card developed by G4EWJ and supported by the BATC Shop
G4KLB
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Joined: Wed May 28, 2008 10:46 am

Raspberry Pi 2

Post by G4KLB » Mon Jul 27, 2015 4:37 pm

I have built two DigiThin's using the Model B, but have a Pi 2 on the shelf! So if anyone is using a Raspberry Pi 2, please post any differences or tips here.

Placement of the links, extended headers etc..... Text, drawings, photos all accepted :D

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G0NMY
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Joined: Wed Nov 11, 2009 6:10 pm

Re: Raspberry Pi 2

Post by G0NMY » Sat Aug 01, 2015 1:00 am

Found a downgrade GPIO cable 40pin down to 26, maybe what you are looking for???

http://thepihut.com/collections/raspber ... 40p-to-26p

Cheers Mark
:D

Post edited because I spelled my name wrong haha :oops: :lol:
http://www.g0nmy.blogspot.co.uk/

¡ʎɐqƎ ɟɟo pɹɐoqʎǝʞ ɐ ʎnq I ǝɯᴉʇ ʇsɐl ǝɥʇ sᴉ sᴉɥʇ

G4KLB
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Re: Raspberry Pi 2

Post by G4KLB » Sat Aug 01, 2015 2:48 am

Thanks Mark

Found out the first 26 pins are exactly the same as the B+, the picture of the cable tends to confirm this.
So looks like I only need to do whatever is needed for the B+ (less work than the Model B! as both I and Q signals are on the header) :D

G0EID
Posts: 15
Joined: Thu Oct 17, 2013 3:19 pm

Re: Raspberry Pi 2

Post by G0EID » Sat Aug 01, 2015 8:05 am

Pi2Q.jpg
Q signal on Pi2
Pi2Q.jpg (359.8 KiB) Viewed 2468 times
For B+ and Pi2, I have lifted Link2, 100R, tombstoned it, then ran the wire directly from pin 35 to the top of the resistor, bypassing pin 23 completely..
I did not want to risk connecting pin 23 and 35 together.
Is there is any risk of damage to either GPIO pin by leaving Link 4 laying down and connecting pin 35 directly to pin 23?
73
Dave – G0EID
Last edited by G0EID on Sat Aug 01, 2015 1:38 pm, edited 1 time in total.

G4EWJ
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Re: Raspberry Pi 2

Post by G4EWJ » Sat Aug 01, 2015 11:52 am

I suppose it's possible if you fitted another board and that was using the pins in a different way, it could cause them to drive against each other.

Brian

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G0NMY
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Re: Raspberry Pi 2

Post by G0NMY » Sat Aug 01, 2015 1:42 pm

Glad you sorted it Brian.
I have just received my Pi-cam for my Pi I was going to order a digi thin kit from batc but they sold out lol.
I have the RX pcb on its way and the Eardek tuner etc So my aim is to get going on 333k narrow band TV Can you tell me what is the required deviation?
I was wondering if I could modify an old 2m PMR rig and maybe a 70cms rig aswell?
I have a big learning curve ahead of me, but hey if ham radio was easy it would not be as appealing
73 Mark
http://www.g0nmy.blogspot.co.uk/

¡ʎɐqƎ ɟɟo pɹɐoqʎǝʞ ɐ ʎnq I ǝɯᴉʇ ʇsɐl ǝɥʇ sᴉ sᴉɥʇ

G4EWJ
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Re: Raspberry Pi 2

Post by G4EWJ » Sat Aug 01, 2015 1:59 pm

Deviation is not a term used in digital TV - that's for FM. Digital TV uses QPSK modulation amongst others, which is more like AM. You can't feed a signal into the modulator of an FM rig.

You may be able to use the PAs, but QPSK needs very linear amplification, so you generally need to under-run any rf amplifier.

Brian

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G0NMY
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Re: Raspberry Pi 2

Post by G0NMY » Sat Aug 01, 2015 2:45 pm

yes sorry Brian I was refering to spectral bandwidth and using the PA stages.
I just didnt word it correctly ;-)
:D
I have a few M67742 PA's but Cant seem to find info on them as to if they are suitable for DATV

Im good at experimenting ( Blowing things up) :lol: :lol:
Cheers Mark
http://www.g0nmy.blogspot.co.uk/

¡ʎɐqƎ ɟɟo pɹɐoqʎǝʞ ɐ ʎnq I ǝɯᴉʇ ʇsɐl ǝɥʇ sᴉ sᴉɥʇ

g8gtz
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Re: Raspberry Pi 2

Post by g8gtz » Sat Aug 01, 2015 7:02 pm

Digithin kits should be back in stock early next week - just as soon as I make some more kits up...

Noel

G4EWJ
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Re: Raspberry Pi 2

Post by G4EWJ » Sat Aug 01, 2015 9:01 pm

I'm not sure about the PAs. I think the more modern RA series has better linearity.

Brian

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