# Polyphase Channelizer Block - How do I deal with the GUI practicalities of 440 source ports?

**URL:** <https://www.ruby-forum.com/t/polyphase-channelizer-block-how-do-i-deal-with-the-gui-practicalities-of-440-source-ports/242397>\
**Category:** GNU Radio\
**Created:** [June 22, 2015, 8:13am UTC](https://www.ruby-forum.com/t/polyphase-channelizer-block-how-do-i-deal-with-the-gui-practicalities-of-440-source-ports/242397 "2015-06-22T08:13:55Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [June 22, 2015, 8:13am UTC](https://www.ruby-forum.com/t/polyphase-channelizer-block-how-do-i-deal-with-the-gui-practicalities-of-440-source-ports/242397/1 "2015-06-22T08:13:55Z")

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Hi,

I’m struggling with the Polyphase Channelizer Block when using a large  
number of channels in gnuradio-companion.

In my application I would like to separate out 440 x 48kHz channels  
spanning 7MHz to 28MHz. Of these only 4 will be of interest to me  
(around the 7,10,14 and 28MHz amateur bands). From my readings, the  
Polyphase Channelizer would appear to be a reasonable starting point in  
terms of processing overhead but I’m not ruling out other methods.

I have looked at:  
[PFB Channelizers and Synthesizers — Rondeau Research](http://www.trondeau.com/examples/2014/1/23/pfb-channelizers-and-synthesizers.html).  
The fm\_channelizer.grc script works well and the CPU load looked  
reasonable. The example script, fm\_channelize\_and\_view.grc, looks to be  
the basis for what I want to do. But from other posts and my own  
experience the busports implementation seems broken.

The problem I am facing is how to handle 440 source ports of the  
Polyphase Channelizer Block using gnuradio-companion. i.e. there are  
too many to be displayed/manipulated within the GUI. I am not  
experienced with the innerworkings of gnuradio but my current thinking  
is to use the first four channel sources of the Polyphase Channelizer  
Block to complete my flow-graph in gnuradio-companion. Then look for  
those references in the .grc file and substitute the correct channels  
with a text editor. What’s scaring me off is terminating the 436  
channels I don’t want with nul sinks!

Any suggestions?

Thanks

Terry Koziniec  
School of Engineering and Information Technology  
Murdoch University