Return-Path: Received: from rly-df01.mx.aol.com (rly-df01.mail.aol.com [172.19.156.14]) by air-df07.mail.aol.com (v125.7) with ESMTP id MAILINDF072-52b4b03cbf8f5; Wed, 18 Nov 2009 05:27:15 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-df01.mx.aol.com (v125.7) with ESMTP id MAILRELAYINDF018-52b4b03cbf8f5; Wed, 18 Nov 2009 05:27:06 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NAhjm-0001Nq-BN for rs_out_1@blacksheep.org; Wed, 18 Nov 2009 10:26:10 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NAhjl-0001Nh-JW for rsgb_lf_group@blacksheep.org; Wed, 18 Nov 2009 10:26:09 +0000 Received: from web28103.mail.ukl.yahoo.com ([217.146.182.123]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1NAhjl-0006bY-CU for rsgb_lf_group@blacksheep.org; Wed, 18 Nov 2009 10:26:09 +0000 Received: (qmail 39863 invoked by uid 60001); 18 Nov 2009 10:26:03 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1258539963; bh=h9KIKuoznmFtkbQjZ49E6fM4mxhOdLX2WcMXIszqZEM=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=RoIh5HrI8B6iz+ThnGHbX5mbpq5j8CWfO1FdBUzWyOAipMukLYtlMbS1L+CbPiYcMarR54kqoegKQBqQqn3pfmGmDi/uD+kej9ZogAq3/L63O2jfF7OjpdXQOWuLfJu2hAzMkvmUFNiIRVU6Gj+4pd4QG/1VbucCx7KDUqwQMqg= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=XQAx9ErbG32qw/qFwV8oQOCuHsYi3SCG1T8EguoYms3qa6atCr/7lVXMd3NEVvlEU5+Vng8AKC48D+/kCLosHy+C3ueFKhbXreOomEDDplHeNPCAS/2jQhrQsdzJ+cE37SKmAZX878OWoyal6YYEB3YHyMsMzvcM3BFw4qXeUVA=; Message-ID: <827574.39630.qm@web28103.mail.ukl.yahoo.com> X-YMail-OSG: V3eddiMVM1kViMbn4pFY_PVcUDBDU33ykJhuKm3TnXA9E2XB_1bmSMJALwb7oto7dfsdiqWzUlt6.EgcazTbbB9Yac9ldVlN45CmfFxedlA79DST4p.wwFJ6YE7oSfoRXPUMq7zonRRZnMWbPfFcC5.nXlS3wD3St3uhbnLE7Wv4KxNMwgsUvJ27BvTWSxpJqpjNc8B5szbOhnOSh2LDH3TGtty.o6pi7_u76mjfcnri_MmnmzyFxqVPZwQ1twDn_VEE1gpOdBUl45_C.llxwT5L6gHAVUJL4MloxrstZsbBl3ytrjfqUAF13sAis2PWkl5d9_6w9aZeJWDznXbeBwoWHVKUmA2xvA-- Received: from [86.140.72.194] by web28103.mail.ukl.yahoo.com via HTTP; Wed, 18 Nov 2009 02:26:03 PST X-Mailer: YahooMailClassic/8.1.6 YahooMailWebService/0.7.361.4 Date: Wed, 18 Nov 2009 02:26:03 -0800 (PST) From: M0FMT To: rsgb_lf_group@blacksheep.org In-Reply-To: <02b601ca6833$4e59f6e0$0517aac0@jimdesk> MIME-Version: 1.0 X-Karma: unknown: DomainKey-Status: good (testing) Subject: RE: LF: Re: G7NKS sidebands Content-Type: multipart/alternative; boundary="0-720041973-1258539963=:39630" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.1 required=5.0 tests=HTML_30_40, HTML_FONTCOLOR_UNKNOWN,HTML_FONT_BIG,HTML_MESSAGE, HTML_TAG_EXISTS_TBODY autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d246.1 ; domain : yahoo.co.uk DKIM : pass --0-720041973-1258539963=:39630 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable OK Jim and LF=20 =A0 Yes when you reduced power from 45w? down to 7w the side bands assuming th= ey were still there but at the same relative level may possibly be=A0unrea= dable by me. 45/7=3D6.4 times reduction 8dB power drop which I think repre= sents -16dB RX strength add that to the say -30dB SB at 45 watts resulting= in, if=A0I have understood this correctly, -46dB side band which is proba= bly below threashold of the Software=A0and I would not see it. I am sure if it was just the fact you had HUM that would not neccessarily= result in IMD there has to be some non linearity for modulation to occur.= =A0The hot PA has to be a clue.=20 =A0 As far as your signal at this QTH goes Jim it is not an issue here I am no= t bothered by your two sidebands at all as you say three for the price of= one ...hee hee. However I cannot think of a simple way to stop me reporti= ng them to the Database other than me closing down.... which may be the so= lution=A0 ... only joking. =A0 73 es GL=A0petefmt=20 --- On Wed, 18/11/09, James Cowburn wrote: From: James Cowburn Subject: RE: LF: Re: G7NKS sidebands To: rsgb_lf_group@blacksheep.org Date: Wednesday, 18 November, 2009, 9:41 Hi Pete =A0 The Rig only gets overly hot on powers over abt 20 watt output and 20%+ du= ty cycle (not to be unexpected given the operation at or beyond the limits= of design). =A0When I run it around 10 to 15 watts and on 10% duty it sta= ys just lightly warm so as far as I can tell there is no discontinuity or= paradox in the ouput/duty/warming matrix!=20 =A0 The sidebands will no doubt be still there, just beyond the limit of detec= tion =A0 =A0 =A0 With best regards =A0 =A0 Jim =A0 =A0 Dr. James Cowburn From: owner- rsgb_lf_group@blacksheep.org [mailto:owner- rsgb_lf_group@bla= cksheep.org ] On Behalf Of M0FMT Sent: 18 November 2009 09:27 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: G7NKS sidebands =A0 Hi LF =A0 I think the issue is intermodulation products caused by over driving the= the linear RF stages of the TX into distortion=A0because when Jim reduces= drive the sidebands petty well disappear at this range. These observation= is based upon test carried out yesterday. There is another issue Jim seem= s to have which is that his PA grossly over heats (I think I am right) whe= n he reduces drive and that shouldn't happen. For modulation to take place= the output=A0of the modulator has to be mixed (hetrodyned) with the RF si= gnal. In this case I am guessing that the carrier is modulated by noise (5= 0c/s say) in the non linear (over driven linear RF stages) in the TX drive= r or output. The fact the PA over heats on reduced drive suggests to me the bias on the= PA transistors is being altered by changes to the drive anther indication= that the TX output may not be entirely linear --- On Wed, 18/11/09, James Moritz wrote: From: James Moritz Subject: LF: Re: G7NKS sidebands To: rsgb_lf_group@blacksheep.org Date: Wednesday, 18 November, 2009, 1:13 Dear Jim LF Group, Looking at the sidebands on the G7NKS WSPR signals, mains hum or other noi= se by itself is not a sufficient explanation of what is seen. Simply addin= g 50Hz, 150Hz, etc. noise into the PC audio channel, then feeding the resu= lt into an SSB TX would give unwanted CW at frequencies offset from the SS= B carrier frequency by +/-50Hz, 150Hz and so on, i.e. with the carrier "di= al frequency" at 502.4kHz, unmodulated carriers would appear at 502.45kHz,= 502.55kHz and so on, in addition to the WSPR signal at around 503.9kHz.= However, these would probably largely be removed by the SSB filter in the= rig. Instead, we see unwanted sidebands offset from the wanted WSPR signa= l frequency by +/- 50Hz, 150Hz, with identical modulation to the wanted si= gnal. This requires some sort of non-linear process to cause the intermodu= lation between the presumed mains noise and the WSPR signal somewhere in= the TX chain. One possibility is that intermodulation occurs in the PA. Jim's descriptio= n suggests that he is persuading the HF PA in the IC735 to produce output= at 500k. At this frequency, the PA linearity may well be poor due to the= impedance matching, coupling, decoupling and feedback components in the= PA being wrong for the frequency, and high flux densities occuring in fer= rite components due to the low operating frequency. But this wouldn't expl= ain why Jim also gets multiple received signals from a strong station with= a clean signal, which implies some identical noise source and distortion= in the receive path. It would also mean the mains noise getting through= the filtering in the rig somehow. A possibility that would explain the unwanted sidebands appearing on both= TX and RX signals is if one of the oscillators in the system has mains no= ise sidebands. The sound card clock seems unlikely, since this is just a= simple crystal oscillator. I see the IC735 has some sort of multi-loop PL= L synthesiser, which would certainly be prone to this type of spurious sig= nal, since any kind of mains noise getting in would modulate the VCO frequ= encies, and would probably be the same on transmit and receive. This could= be checked by receiving a clean carrier somewhere around 500kHz, and exam= ining the audio output using Spec Lab or Argo or similar to see if 50Hz an= d 150Hz sidebands are present on the received audio tone. Cheers, Jim Moritz 73 de M0BMU ----- Original Message ----- From: "James Cowburn" To: Sent: Monday, November 16, 2009 8:26 PM Subject: LF: rule #2 - assumption is the brother of all foul ups > LF >=20 >=20 >=20 > Sidebands are back!=A0 I think its caused by my TX getting hot and bothe= red by > struggling at 500.=A0 From cold it txs 50 watts but this soon drops back= to > around 35, and the sidebands appear.=A0 My sigs are better so having the= txfr > outside the shack and at the antenna is a vast improvement, but I now ne= ed > to work on the cooling. =A0 =20 --0-720041973-1258539963=:39630 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
OK Jim and LF
 
Yes when you reduced power from 45w? down to 7w the side bands assumi= ng they were still there but at the same relative level may possibly be&nb= sp;unreadable by me. 45/7=3D6.4 times reduction 8dB power drop which I thi= nk represents -16dB RX strength add that to the say -30dB SB at 45 watts= resulting in, if I have understood this correctly, -46dB side band= which is probably below threashold of the Software and I would not= see it.
I am sure if it was just the fact you had HUM that would not neccessa= rily result in IMD there has to be some non linearity for modulation to oc= cur. The hot PA has to be a clue.
 
As far as your signal at this QTH goes Jim it is not an issue here I= am not bothered by your two sidebands at all as you say three for the pri= ce of one ...hee hee. However I cannot think of a simple way to stop me re= porting them to the Database other than me closing down.... which may be= the solution  ... only joking.
 
73 es GL petefmt

--- On Wed, 18/11/09, James Cowburn= <james.cowburn@virgin.net> wrote:

From: James Cowburn <james.cowburn@virgin.n= et>
Subject: RE: LF: Re: G7NKS sidebands
To: rsgb_lf_group@blacks= heep.org
Date: Wednesday, 18 November, 2009, 9:41

Hi Pete

 =

The Rig only gets ov= erly hot on powers over abt 20 watt output and 20%+ duty cycle (not to be= unexpected given the operation at or beyond the limits of design).  = When I run it around 10 to 15 watts and on 10% duty it stays just lightly= warm so as far as I can tell there is no discontinuity or paradox in the= ouput/duty/warming matrix!

 =

The sidebands will= no doubt be still there, just beyond the limit of detection=

 =

 =

 =

With best regards

=  

=  

Jim

=  

=  

Dr. James Cowburn

From:= owner- rsgb_lf_group@blacksheep.org [mailto:owner- rsgb_lf_group@= blacksheep.org ] On Behalf Of = M0FMT
Sent: 18 Nove= mber 2009 09:27
To: rsg= b_lf_group@blacksheep.org
Subject:= Re: LF: Re: G7NKS sidebands

 

Hi LF

 

I think the issue is intermodulation products caused= by over driving the the linear RF stages of the TX into distortion b= ecause when Jim reduces drive the sidebands petty well disappear at this= range. These observation is based upon test carried out yesterday. There= is another issue Jim seems to have which is that his PA grossly over heat= s (I think I am right) when he reduces drive and that shouldn't happen. Fo= r modulation to take place the output of the modulator has to be mixe= d (hetrodyned) with the RF signal. In this case I am guessing that the car= rier is modulated by noise (50c/s say) in the non linear (over driven line= ar RF stages) in the TX driver or output.

The fact the PA over heats on reduced drive suggests= to me the bias on the PA transistors is being altered by changes to the= drive anther indication that the TX output may not be entirely linear
=
--- On Wed, 18/11/09, James Morit= z <james.moritz@btopenworld.com&g= t; wrote:


From: James Moritz &l= t;james.moritz@btopenworld.com>
Subject: LF: Re: G7NKS sidebands
= To: rsgb_lf_group@blacksheep.org
Date: Wednesday, 18 November, 2009, 1:= 13

Dear Jim LF Group,
Looking at the sidebands on the G7NKS WSPR signals, mains hum or other no= ise by itself is not a sufficient explanation of what is seen. Simply addi= ng 50Hz, 150Hz, etc. noise into the PC audio channel, then feeding the res= ult into an SSB TX would give unwanted CW at frequencies offset from the= SSB carrier frequency by +/-50Hz, 150Hz and so on, i.e. with the carrier= "dial frequency" at 502.4kHz, unmodulated carriers would appear at 502.45= kHz, 502.55kHz and so on, in addition to the WSPR signal at around 503.9kH= z. However, these would probably largely be removed by the SSB filter in= the rig. Instead, we see unwanted sidebands offset from the wanted WSPR= signal frequency by +/- 50Hz, 150Hz, with identical modulation to the wan= ted signal. This requires some sort of non-linear process to cause the int= ermodulation between the presumed mains noise and the WSPR signal somewhere in the TX chain.
One possibility is that intermodulation occurs in the PA. Jim's desc= ription suggests that he is persuading the HF PA in the IC735 to produce= output at 500k. At this frequency, the PA linearity may well be poor due= to the impedance matching, coupling, decoupling and feedback components= in the PA being wrong for the frequency, and high flux densities occuring= in ferrite components due to the low operating frequency. But this wouldn= 't explain why Jim also gets multiple received signals from a strong stati= on with a clean signal, which implies some identical noise source and dist= ortion in the receive path. It would also mean the mains noise getting thr= ough the filtering in the rig somehow.

A possibility that would exp= lain the unwanted sidebands appearing on both TX and RX signals is if one= of the oscillators in the system has mains noise sidebands. The sound car= d clock seems unlikely, since this is just a simple crystal oscillator. I see the= IC735 has some sort of multi-loop PLL synthesiser, which would certainly= be prone to this type of spurious signal, since any kind of mains noise= getting in would modulate the VCO frequencies, and would probably be the= same on transmit and receive. This could be checked by receiving a clean= carrier somewhere around 500kHz, and examining the audio output using Spe= c Lab or Argo or similar to see if 50Hz and 150Hz sidebands are present on= the received audio tone.

Cheers, Jim Moritz
73 de M0BMU

=
----- Original Message ----- From: "James Cowburn" <james.cowburn@virgin.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Monday, November 16, 2009 8:26 PM
Subject: LF: rule #2 - assumption is the bro= ther of all foul ups


> LF
>
>
>
>= Sidebands are back!  I think its caused by my TX getting hot and bot= hered by
> struggling at 500.  From cold it txs 50 watts but th= is soon drops back to
> around 35, and the sidebands appear. = My sigs are better so having the txfr
> outside the shack and at th= e antenna is a vast improvement, but I now need
> to work on the coo= ling.

 


=20 --0-720041973-1258539963=:39630--