[Lowfer] Poor man's mw/lw wideband noise reduction

[Peter Cranwell]

I would appreciate a copy.

Thanks

Pete
----- Original Message ----- 
From: "Dave Brown" <tractorb at ihug.co.nz>
To: "Discussion of the Lowfer (US, European, &amp;UK) and MedFer bands" 
<lowfer at mailman.qth.net>
Sent: Sunday, January 11, 2009 6:44 AM
Subject: Re: [Lowfer] Poor man's mw/lw wideband noise reduction


> An LF oriented phasing system of this type was originally described by
> the late ZL2BBJ in the ZL amateur radio journal 'Break-In' in October
> 1996.  Another version built by George, ZL3PN was published in the
> November 1996 issue.
> The October 1998 LF column in Break-In described yet another version
> built by the late ZL3VN. These all differ from the VK5BR version (AR,
> 2000)  that Scott referenced, primarily in the use of discrete
> bipolars or FETs, rather than op-amps.  I can arrange copies for those
> interested.
> 73
> Dave, ZL3FJ
>
> ----- Original Message ----- 
> From: "Scott Tilley" <sthed475 at telus.net>
> To: "Discussion of the Lowfer (US, European, &amp;UK) and MedFer
> bands" <lowfer at mailman.qth.net>
> Sent: Sunday, January 11, 2009 8:33 AM
> Subject: Re: [Lowfer] Poor man's mw/lw wideband noise reduction
>
>
>> HI Paul
>>
>> A method  used here done with a small 'noise' antenna and my LF
>> 'sense'
>> antenna and then mixing the two RF signals together produces
>> excellent
>> results and even allowed me to work the Yukon from within the City
>> of
>> Vancouver...  Normally a phase shifting network is used on the noise
>> signal to allow one to first adjust the phase of the noise signal
>> 180
>> degrees of the received noise on the sense antenna.  Once you have
>> adjusted the phase then the amplitude of the two RF signals is
>> adjusted
>> such that the offending signal is canceled.  This is really an
>> iterative
>> thing as each back and forth adjustment further improves the
>> canceling.
>>
>> I use such a device on 2200m to deal with my one neighbour's light
>> dimmer.   It also works (very well I might add) on any signals you
>> receive on both antennas so it can be used to cancel local NDBs for
>> example so you you can hear the DX ones on the same frequency...
>>
>> See here for a design I modified for 2200m.  It works well in the
>> lowfer
>> band to 600m as described...
>>
>> http://users.tpg.com.au/users/ldbutler/LFNoiseCancel.htm
>>
>> Also see
>> http://www.alg.myzen.co.uk/radio/136/pre_sel.htm
>>
>> 73 Scott
>> VE7TIL
>>
>>
>> PAUL DAULTON wrote:
>>>
>>> I found an article in Elektor magazine feb 2005, which can be
>>> downloaded from Elektors's site, about
>>>
>>> a noise reduction method.
>>>
>>>
>>>
>>> Basically two receivers are used.The loudspeaker outputs of the two
>>> radios are connected in phase while
>>>
>>> the speaker in the second rec is disconnected. With the second
>>> receiver tuned a little higher or lower than
>>>
>>> the main one the speaker of the main receiver is fed with the
>>> difference between the two signals. External
>>>
>>> antennas should be connected in parallel. Using the volume
>>> adjustment
>>> on the second radio a setting can be
>>>
>>> found that should result in a reduction of noise.
>>>
>>>
>>>
>>> Sounds good I am trying to figure out how to apply to Argo
>>> connections.
>>>
>>>
>>>
>>> Any comments?
>>>
>>>
>>>
>>> Paul K5wms
>>>
>>> ------------------------------------------------------------------------
>>>
>>> _______________________________________________
>>> >From the Lowfer mailing list
>>> Send messages to: Lowfer at mailman.qth.net
>>> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer
>>>
>> _______________________________________________
>>>From the Lowfer mailing list
>> Send messages to: Lowfer at mailman.qth.net
>> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer
>
>
> --------------------------------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com
> Version: 8.0.176 / Virus Database: 270.10.5/1885 - Release Date:
> 9/01/2009 19:59
>
> _______________________________________________
>>From the Lowfer mailing list
> Send messages to: Lowfer at mailman.qth.net
> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer
>