# Some guidance on working through Core concepts of GNU Radio

**URL:** <https://www.ruby-forum.com/t/some-guidance-on-working-through-core-concepts-of-gnu-radio/229989>\
**Category:** GNU Radio\
**Created:** [May 26, 2014, 3:41am UTC](https://www.ruby-forum.com/t/some-guidance-on-working-through-core-concepts-of-gnu-radio/229989 "2014-05-26T03:41:17Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jason\_sam](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7993a0/32.png) [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\
**Post date:** [May 26, 2014, 3:41am UTC](https://www.ruby-forum.com/t/some-guidance-on-working-through-core-concepts-of-gnu-radio/229989/1 "2014-05-26T03:41:17Z")

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Im working through  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsCoreConcepts](http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsCoreConcepts)

Ive created the flow graph:

Im unsure on how to address the problem reported on Complex to Mag^2 as  
below, could you offer some pointers please?

Connection (  
Block - blocks\_complex\_to\_mag\_squared\_0 - Complex to  
Mag^2(blocks\_complex\_to\_mag\_squared)  
Source - out(0)  
Block - blocks\_file\_sink\_0 - File Sink(blocks\_file\_sink)  
Sink - in(0)  
):  
Source IO size “4096” does not match sink IO size "8192.

Thanks.

Cheers, Shane

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**Author:** ![Shane\_MacPhillamy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/779978/32.png) [@Shane\_MacPhillamy](https://www.ruby-forum.com/u/Shane_MacPhillamy)\
**Post date:** [May 26, 2014, 3:51am UTC](https://www.ruby-forum.com/t/some-guidance-on-working-through-core-concepts-of-gnu-radio/229989/2 "2014-05-26T03:51:08Z")

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On 05/25/2014 09:39 PM, Shane MacPhillamy wrote:

> Connection (  
> Cheers, Shane
> 
> * * *
> 
> Discuss-gnuradio mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)  
> complex-to-mag\*\*2 produces a _real_ float output, and you’re configuring  
> your sink (or left it defaulted) to float-complex. GRC will have turned  
> the arrow _red_ to emphasize that the output type of one block  
> doesn’t match the input type of another, further, under the errors  
> dialog, it  
> would have noted the same thing.

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**Author:** ![Shane\_MacPhillamy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/779978/32.png) [@Shane\_MacPhillamy](https://www.ruby-forum.com/u/Shane_MacPhillamy)\
**Post date:** [May 26, 2014, 7:12am UTC](https://www.ruby-forum.com/t/some-guidance-on-working-through-core-concepts-of-gnu-radio/229989/3 "2014-05-26T07:12:23Z")

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> > Cheers, Shane
> 
> –  
> Marcus L.  
> Principal Investigator  
> Shirleys Bay Radio Astronomy Consortium  
> [http://www.sbrac.org](http://www.sbrac.org)
> 
> * * *
> 
> Discuss-gnuradio mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)

On 26 May 2014, at 11:49 am, Marcus D. Leech [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

Thank you. The arrow is now black.