# QT Sink center frequency not working

**URL:** <https://www.ruby-forum.com/t/qt-sink-center-frequency-not-working/230512>\
**Category:** GNU Radio\
**Created:** [June 20, 2014, 11:42pm UTC](https://www.ruby-forum.com/t/qt-sink-center-frequency-not-working/230512 "2014-06-20T23:42:47Z")\
**Posts on this page:** 4\
**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:** [June 20, 2014, 11:42pm UTC](https://www.ruby-forum.com/t/qt-sink-center-frequency-not-working/230512/1 "2014-06-20T23:42:47Z")

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Setting the center frequency in the QT Sink doesn’t seem to work. It  
stays centered at 0 Hz. Center frequency seems to work fine with regular  
QT Frequency Sink. GNU Radio version is v3.7.4git-332-g34ee3b7d. I  
attached a GRC file.

Sean  
?

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<div class="post-metadata">

**Author:** ![NowlanS\_Sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/f05b48/32.png) [@NowlanS\_Sean](https://www.ruby-forum.com/u/NowlanS_Sean)\
**Post date:** [June 23, 2014, 4:32pm UTC](https://www.ruby-forum.com/t/qt-sink-center-frequency-not-working/230512/2 "2014-06-23T16:32:15Z")

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On Fri, Jun 20, 2014 at 5:41 PM, Nowlan, Sean  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Setting the center frequency in the QT Sink doesn’t seem to work. It  
> stays centered at 0 Hz. Center frequency seems to work fine with regular QT  
> Frequency Sink. GNU Radio version is v3.7.4git-332-g34ee3b7d. I attached  
> a GRC file.
> 
> Sean

Hmm… just tested your example GRC file here and it worked fine for me.

Tom

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<div class="post-metadata">

**Author:** ![NowlanS\_Sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/f05b48/32.png) [@NowlanS\_Sean](https://www.ruby-forum.com/u/NowlanS_Sean)\
**Post date:** [June 23, 2014, 5:22pm UTC](https://www.ruby-forum.com/t/qt-sink-center-frequency-not-working/230512/3 "2014-06-23T17:22:46Z")

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On Fri, Jun 20, 2014 at 5:41 PM, Nowlan, Sean  
\<removed\_email\_address@domain.invalid[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)\> wrote:  
Setting the center frequency in the QT Sink doesn’t seem to work. It  
stays centered at 0 Hz. Center frequency seems to work fine with regular  
QT Frequency Sink. GNU Radio version is v3.7.4git-332-g34ee3b7d. I  
attached a GRC file.

Sean

Hmm… just tested your example GRC file here and it worked fine for me.

Tom

Strange. I’m using the latest git revision on master. PyQt4 version is  
4.10.4. Any other ideas?

Sean

---

<div class="post-metadata">

**Author:** ![NowlanS\_Sean](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/f05b48/32.png) [@NowlanS\_Sean](https://www.ruby-forum.com/u/NowlanS_Sean)\
**Post date:** [June 24, 2014, 12:47pm UTC](https://www.ruby-forum.com/t/qt-sink-center-frequency-not-working/230512/4 "2014-06-24T12:47:28Z")

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Well, that would help, wouldn’t it! D’oh. Thanks!

Sean

From: Nowlan, Sean  
Sent: Monday, June 23, 2014 1:39 PM  
To: ‘Tom R.’  
Subject: RE: [Discuss-gnuradio] QT Sink center frequency not working

Ah. The shame. Thanks!

From: removed\_email\_address@domain.invalid[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
[[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Tom R.  
Sent: Monday, June 23, 2014 11:23 AM  
To: Nowlan, Sean  
Subject: Re: [Discuss-gnuradio] QT Sink center frequency not working

Stupid question, but you are clicking the “Display RF Frequencies” check  
box, right?

Tom

On Mon, Jun 23, 2014 at 11:21 AM, Nowlan, Sean  
\<removed\_email\_address@domain.invalid[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)\> wrote:  
On Fri, Jun 20, 2014 at 5:41 PM, Nowlan, Sean  
\<removed\_email\_address@domain.invalid[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)\> wrote:  
Setting the center frequency in the QT Sink doesn’t seem to work. It  
stays centered at 0 Hz. Center frequency seems to work fine with regular  
QT Frequency Sink. GNU Radio version is v3.7.4git-332-g34ee3b7d. I  
attached a GRC file.

Sean

Hmm… just tested your example GRC file here and it worked fine for me.

Tom

Strange. I’m using the latest git revision on master. PyQt4 version is  
4.10.4. Any other ideas?

Sean