Return-Path: Received: from rly-db04.mx.aol.com (rly-db04.mail.aol.com [172.19.130.79]) by air-db08.mail.aol.com (v125.7) with ESMTP id MAILINDB082-abf4b03bfcf128; Wed, 18 Nov 2009 04:35:22 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-db04.mx.aol.com (v125.7) with ESMTP id MAILRELAYINDB045-abf4b03bfcf128; Wed, 18 Nov 2009 04:35:12 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NAgvj-0000kx-CG for rs_out_1@blacksheep.org; Wed, 18 Nov 2009 09:34:27 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NAgvi-0000ko-OS for rsgb_lf_group@blacksheep.org; Wed, 18 Nov 2009 09:34:26 +0000 Received: from web28102.mail.ukl.yahoo.com ([217.146.182.122]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1NAgvi-00062i-IF for rsgb_lf_group@blacksheep.org; Wed, 18 Nov 2009 09:34:26 +0000 Received: (qmail 35968 invoked by uid 60001); 18 Nov 2009 09:34:20 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1258536860; bh=+T+Sf8imC7ccjqFvOdG8rnGX89qmABh9ZYISG7+FOYo=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type; b=J0nZaIio0Osnn+7ZUSzUbFPumncnyaVUHAIBW2wel/320HUzpDJ8Nyv4KrACKlTBllHeT9TP+fhBqsbM/hPEz6G4Z9fxZH30w0wMnRr0BOHMIYu7VW3pKqdkZyBdGzvnvc6N0HPWYgeQJTvOacRAKaTRnJ+8+nWYe4IKIh7dXxs= 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:MIME-Version:Content-Type; b=FKg/kE4YN1smyBS6ig1tYL4YDsLCyzOBeYHJOyN05Vj+RUwSPQu9Et7QLX8tqMrfoGtAtGIyeMLGXiLfTOhJIZPCfXoxlaTaQzo0CFiIBaPE65D/EK9KDYXfXg3NIotXbSxBwZj30drKpX9rsdYHlCR0ndR3ar7wYLDrst7QYmM=; Message-ID: <798375.34836.qm@web28102.mail.ukl.yahoo.com> X-YMail-OSG: cKum_rMVM1nQbfnSXeK6liu_vr7qRz6pOLA84OrkRWFBst251HvwNf4cv1qLD5jYYONt8VNWIUoPXVwDRWtEuL06FKHetsKXD82EvIUTo2U.qWe8Zr31EkMAh0Oe8XNYxA2zYr9zcYHXNULNpFbL2D7XMhGQ0yNH6PGugA6TlHbxoUjKPDaO4ZaUp6lzmfdOK.mzA.rWJJ9i7b03aGpqjn_gjbkZ8cm.K.lHG6v.TOnQfcHzzY9kEzODQ7VYvHQsSo.AX9JlCZ6.Npw3dnJPYSvN1MyZ9wg9B9j8SZVzSgo6hopEli_xQlOX8vadMZgrjzsgNdnFJg9PJg-- Received: from [86.140.72.194] by web28102.mail.ukl.yahoo.com via HTTP; Wed, 18 Nov 2009 09:34:20 GMT X-Mailer: YahooMailClassic/8.1.6 YahooMailWebService/0.7.361.4 Date: Wed, 18 Nov 2009 09:34:20 +0000 (GMT) From: M0FMT To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Karma: unknown: DomainKey-Status: good (testing) Subject: Fw: Re: LF: Re: G7NKS sidebands Content-Type: multipart/alternative; boundary="0-555521107-1258536860=:34836" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=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-m251.2 ; domain : yahoo.co.uk DKIM : pass --0-555521107-1258536860=:34836 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Hi agn LF =A0 Sorry didn't finish my train of thought before the wonderfully world of Vi= sta decided prematurely to send the mail and I didn't get a chance to gram= mar and spell check it but hopefully the message got across. =A0 73 petefmt =A0 --- On Wed, 18/11/09, M0FMT wrote: From: M0FMT Subject: Re: LF: Re: G7NKS sidebands To: rsgb_lf_group@blacksheep.org Date: Wednesday, 18 November, 2009, 9:26 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. =20 --0-555521107-1258536860=:34836 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable


Hi agn LF
 
Sorry didn't finish my train of thought before the wonderfully world= of Vista decided prematurely to send the mail and I didn't get a chance= to grammar and spell check it but hopefully the message got across.
 
73 petefmt
 
--- On Wed, 18/11/09, M0FMT <m0fmt@yahoo.co.uk&= gt; wrote:

From: M0FMT <m0fmt@yahoo.co.uk>
Subje= ct: Re: LF: Re: G7NKS sidebands
To: rsgb_lf_group@blacksheep.org
Dat= e: Wednesday, 18 November, 2009, 9:26

Hi LF
 
I think the issue is intermodulation products caused by over driving= the the linear RF stages of the TX into distortion because when Jim= reduces drive the sidebands petty well disappear at this range. These obs= ervation is based upon test carried out yesterday. There is another issue= Jim seems to have which is that his PA grossly over heats (I think I am= right) when he reduces drive and that shouldn't happen. For modulation to= take place the output of the modulator has to be mixed (hetrodyned)= with the RF signal. In this case I am guessing that the carrier is modula= ted by noise (50c/s say) in the non linear (over driven linear 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 ind= ication that the TX output may not be entirely linear

--- On Wed= , 18/11/09, James Moritz <james.moritz@btopenworld.com>= wrote:

From: James Moritz <james.moritz@btopenworl= d.com>
Subject: LF: Re: G7NKS sidebands
To: rsgb_lf_group@blacksh= eep.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 noise by itself is not a su= fficient explanation of what is seen. Simply adding 50Hz, 150Hz, etc. nois= e into the PC audio channel, then feeding the result 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 502.4= kHz, 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 signal frequency by +/- 50= Hz, 150Hz, with identical modulation to the wanted signal. This requires= some sort of non-linear process to cause the intermodulation 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 description suggests that= he is persuading the HF PA in the IC735 to produce output at 500k. At thi= s frequency, the PA linearity may well be poor due to the impedance matchi= ng, 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 ge= ts multiple received signals from a strong station with a clean signal, wh= ich 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 sideban= ds appearing on both TX and RX signals is if one of the oscillators in the= system has mains noise sidebands. The sound card clock seems unlikely, si= nce this is just a simple crystal oscillator. I see the IC735 has some sor= t 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 modula= te the VCO frequencies, and would probably be the same on transmit and rec= eive. This could be checked by receiving a clean carrier somewhere around= 500kHz, and examining the audio output using Spec 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 Messa= ge ----- From: "James Cowburn" <james.cowburn@virgin.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Monday, Nov= ember 16, 2009 8:26 PM
Subject: LF: rule #2 - assumption is the brother= of all foul ups


> LF
>
>
>
> Sidebands are= back!  I think its caused by my TX getting hot and bothered by
&g= t; struggling at 500.  From cold it txs 50 watts but this soon drops= back to
> around 35, and the sidebands appear.  My sigs are be= tter so having the txfr
> outside the shack and at the antenna is a= vast improvement, but I now need
> to work on the cooling.

<= BR>



=20 --0-555521107-1258536860=:34836--