[600MRG] QEX Noise Canceller

Wed Apr 1 15:10:59 CDT 2015

Depending on model no. is either $1000/pc or $2.58/pc.  The last one 
listed as QHW2201QT7, Digikey has 8231 in inventory.

"The QHx220 integrates the sampler path LNA gain stages as well as 
the DACs required to control the I and Q control voltages (used to 
set the magnitude and phase of the cancellation signal). Both the 
gain, and control voltages are programmable using a SPI bus 
interface." Quote from the webpage.

Too bad it will not work on 2m.  I could use it.

73, Ed - KL7uW

At 11:17 AM 4/1/2015, Warren K2ORS wrote:
>I did some Googling and found the Quellen (Now part of Intersil) chip:
>
>https://www.intersil.com/en/products/other-analog/noise-canceller/isolation-enhancer-noise-cancellation/QHX220.html
>
>    Its spec'd for 300MHz-3GHz and can reduce noise by 20dB.
>
>73 Warren
>
>
>
>
>On 4/1/2015 2:48 PM, Marshall Cross wrote:
>>Yes agree, but Quellen chip is not just subtracting S/Ns out of 
>>phase. I don't know their status, check the internet. 73, Marshall W1HK
>>
>>-----Original Message-----
>>From: 600MRG [mailto:600mrg-bounces at w7ekb.com] On Behalf Of Edward R Cole
>>Sent: Wednesday, April 01, 2015 1:09 PM
>>To: 600MRG at w7ekb.com
>>Subject: Re: [600MRG] QEX Noise Canceller
>>
>>Hmm,
>>
>>I wonder if it was a mini-SDR which in the digital realm notched 
>>the signal frequency so only noise sidebands were captured and 
>>those were inverted in phase to cancel noise with only cleaned up 
>>signal reconverted to analog?
>>
>>As I understand noise cancelling one needs to take S+N and vector 
>>subtract N.  Subtraction is accomplished by adding a 180 degree 
>>phase shifted noise signal.
>>
>>If you simply take S+N and subtract S+N you get a quiet receiver 
>>with nothing output.
>>
>>Does this chip still exist and what does it cost?
>>
>>73, Ed - KL7uW
>>
>>At 08:44 AM 4/1/2015, Marshall Cross wrote:
>>>Lee, I am not an expert on noise cancelling.....however back 5 or 6
>>>years we had a contract from NAB to develop an embedded antenna for
>>>VHF/UHF DTV reception within laptop/net-book computers. The noise
>>>inside such devices at VHF and UHF is very high, even using miniature
>>>electro-statically shielded loops it still restricted coverage, so we
>>>looked for a way to cancel out the broadband noise created by the
>>>digital circuits. What we found, and conducted experiments with, was a
>>>chip made by Quellen, Santa Clara, CA. It did not require a separate
>>>noise sensing antenna in that it was simply inserted in series with the
>>>mini coax from our embedded antenna. And it really worked! So the other
>>>day when the subject of needing a second antenna (for noise sampling)
>>>with exactly the same characteristics as the main antenna came up, I
>>>remembered my work with the Quellen chip which did not require a second
>>>antenna.
>>>Hope this helps, 73, Marshall, W1HK, #41
>>>
>>>-----Original Message-----
>>>From: Lee Mushel [mailto:herbert3 at centurytel.net]
>>>Sent: Wednesday, April 01, 2015 12:27 PM
>>>To: Marshall Cross; kgordon2006 at frontier.com
>>>Cc: 600MRG at w7ekb.com
>>>Subject: Re: [600MRG] QEX Noise Canceller
>>>
>>>Forgive me for asking this but I am not at all sure I've read all the
>>>postings on this thread (mechanical breakdown of my snowplow and since
>>>I am not at all sure winter is over it such repair came first) but I
>>>find it most interesting and I would like to know if any others have
>>>stepped up to say
>>>they have built the QEX noise canceller.   I do have the article sitting
>>>beside me and one of the things that has intrigued me in the past is my
>>>Flex Radio 5000A with two completely independent receivers tied to a common
>>>oscillator for phase control.   This was done by Flex to provide dual
>>>diversity operation and, later, to allow virtual "rotation" of fixed
>>>antennas for noise control and signal enhancement.   While Flex has one of
>>>their "white papers" which discusses proper operation of this feature I had
>>>proceeded to install what I felt was a suitable antenna arrangement.   I
>>>have two DX Engineering Hustler antennas.  One is located next to the
>>>House (read "shack") and the other some 350 feet away farther up my
>>>hill and fed
>>>with fairly good Andrew feedline (negligible losses).   I have long used the
>>>Flex5000A's ability to display simultaneous visual signals from the two
>>>antennas and have even extended this idea to allow me to display
>>>signals into and outof  two meter local repeaters (much to the dismay
>>>of some, I assure you!).
>>>
>>>If someone has responded with a "yes, I've built it" I would appreciate
>>>it if someone would forward that note to me.  I'd like to know of his
>>>experience.   Of course, I can easily see the difference in "noise" from my
>>>present equipment but since I do have some 50 plus years of soldering
>>>experience and do have a smart tweezers so I can wind inductors with
>>>known values.
>>>
>>>73
>>>
>>>Lee  K9WRU/32 I guess
>>>----- Original Message -----
>>>From: "Marshall Cross" <mcross at megawave.com>
>>>To: <kgordon2006 at frontier.com>
>>>Cc: <600MRG at w7ekb.com>
>>>Sent: Monday, March 30, 2015 11:59 AM
>>>Subject: Re: [600MRG] QEX Noise Canceller
>>>
>>>
>>>>Then why not use the same antenna with a splitter?
>>>>
>>>>Sent from my iPhone
>>>>
>>>>>On Mar 30, 2015, at 12:32 PM, Kenneth G. Gordon
>>>>><kgordon2006 at frontier.com> wrote:
>>>>>
>>>>>>On 30 Mar 2015 at 8:56, Frank Lotito wrote:
>>>>>>
>>>>>>Has anyone tried the noise canceller circuit presented in the Jan
>>>>>>/ Feb
>>>>>>2012
>>>>>>issue of QEX? Specifically, for the 600 / 630 meter bands?  The
>>>>>>article by Fred Brown, W6HPH, is titled "End Man-Made Noise with
>>>>>>the Noise Canceller,"
>>>>>>pages 12
>>>>>>through 14.  The author alludes to tailoring the design for the
>>>>>>frequency band of interest.  The QEX article presents a 75 meter
>>>>>>design.
>>>>>>
>>>>>>73 Frank K3DZ / WH2XHA
>>>>>
>>>>>Frank (and others):
>>>>>
>>>>>There was a truly excellent article in Electric Radio Magazine for
>>>>>February
>>>>>2014 on noise cancellers by Mike Murphy WU2D.
>>>>>
>>>>>The final unit he described both reduced his own noise level by +25
>>>>>dB and is adaptable, easily, to any band or frequency.
>>>>>
>>>>>He made the point that for any noise canceller, the only really
>>>>>effective "noise antenna" is an exact duplicate of your normal 
>>>>>receiving antenna.
>>>>>
>>>>>Mike is quite a character and is very talented. I sometimes wish he
>>>>>was a member of this forum.
>
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73, Ed - KL7UW
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