Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w6FLE91L029593 for ; Sun, 15 Jul 2018 23:14:12 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1feoGz-0003rp-FJ for rs_out_1@blacksheep.org; Sun, 15 Jul 2018 22:09:41 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1feoGy-0003rg-UN for rsgb_lf_group@blacksheep.org; Sun, 15 Jul 2018 22:09:40 +0100 Received: from mout.gmx.net ([212.227.15.15]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1feoGv-0005HO-Rh for rsgb_lf_group@blacksheep.org; Sun, 15 Jul 2018 22:09:39 +0100 Received: from Clemens0811 ([79.223.8.13]) by mail.gmx.com (mrgmx001 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MHXXo-1fdhoS1hUa-003PFH for ; Sun, 15 Jul 2018 23:09:36 +0200 From: "Clemens Paul" To: References: <50f24ef2-2d1d-b537-7d66-e6d12ecf8cc3@n1bug.com> <8e720108-88eb-11a7-4f41-ef67c7ae74c9@n1bug.com> <1UQWeI91kE.7cbTRbTeCVJ@optiplex980-pc> <1UQWn0FzVr.1HxCa9v5tM0@optiplex980-pc> In-Reply-To: Date: Sun, 15 Jul 2018 23:09:35 +0200 Message-ID: MIME-Version: 1.0 X-Mailer: Microsoft Office Outlook 11 Thread-Index: AdQcCFtwDe6sc84jSM2lcRTv7NBrxQAcB83gAAHdsdA= X-MimeOLE: Produced By Microsoft MimeOLE X-Provags-ID: V03:K1:Rn91QL27+ejgOVC3vDi763Pc2OpMEqpmUrgMVO1U2cZX9Cv2U/h Fgf0/+7fruXWh97elwTk+zZ5CHGx4WaLz/tuJxjexZskwBuVRbkzIATO+KOJaq2L8Z2D2Of Ac1xjDf5X5soWEj1lZXt91OFimfWv2+Z1yLbXPZBLNasK21pJ0R1o2t1b8qr3/QQ7Y6xsOq E1Sy9Ho0VW83dG7VL9jrQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:6DbCK7n0pGQ=:mTpESPhzcHfJIqpU9wDJ4y 1arIQp1kenw8Fwt1R5D+myePrIh5c+nWw4bNyCqOMNI8+Uxj8CAIE8KA7zZaHc5Rt1vY2s/42 DMmqNYFlCYfHe/eTjJJ6D7/KktkMjbB+ApgU/IO1xdcXUaMjD8wUNJPocjAjIvAVq3kZGiAdA tBwuXxXjMsJ//PW/VSDvQD3Ko4szYI4FneZUVm0Tmfm57KAAy8M8wF8qyLdfUG8oHeVfJ4Xb2 tE4I645QHBaXBEv2dMLD0FqR10vuAvqhGAWuCQqpHOX0IOkqWYAmkLFcEb7fChGsBwyTNsjcD wGpvxBNV9F1TDyKRpdwZhz35flQVcE6shxh+K5IGSPLDPvZUbb9AvoOjuWsXwaUgYeJFfG5aF i/oTzz9YG/RWsFY7uF+n/EJHT7OtFSWHdAoqsKhWSQYDn36CasEooEorrMKIC8LDfsYcluwXR SbN5NPprAt47XNRVcL37vqA4pYxtn3uz7UBRnR+EB4zeTMI8Sb5IawVfMl7OZ2eEF35UkF2Kd q3HdTWfaF429TngatxeqfQ9h8nv6PYOB+uggFVaI0ouI6VivPNl25Nz+ZaHRmMlDcTFYuYXIJ sPO1CferJstJ7NMxu91RSOHohyoiwCjrPiNvHOrngHB47NuFmdYKQVgV8DuIBhSSECdJRzPBe cdkW6JuHM4S6NfW6g5OiDCbgRGSfvn3KB0tK+7LGId0vCagE85rQE4uWXm4YN2G3DTVJ8AsM2 s3bqT8iwuB3Li79lk2+zCxy9pdounimsin4ORsdwMEtsKBZWkqcqo+3kDF+9TBCS3FGrCC9q1 Q9NKHE2 X-Spam-Score: -0.7 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Correction: I wrote: >So noise figure is 21dB. It should have read 22dB. [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [212.227.15.15 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (cpaul[at]gmx.net) -0.0 SPF_PASS SPF: sender matches SPF record -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: 3a21c85df7468d917c96c4564305897b Subject: RE: LF: RE: Simple transverter for 472kHz Content-Type: text/plain; charset="iso-8859-1" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=2.0 required=5.0 tests=DRASTIC_REDUCED 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 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by klubnl.pl id w6FLE91L029593 Correction: I wrote: >So noise figure is 21dB. It should have read 22dB. 73 Clemens DL4RAJ >-----Original Message----- >From: owner-rsgb_lf_group@blacksheep.org >[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Clemens Paul >Sent: Sunday, July 15, 2018 10:43 PM >To: rsgb_lf_group@blacksheep.org >Subject: RE: LF: RE: Simple transverter for 472kHz > >Hello Andy, > >>Yes, I agree with your figures and they are terrible. -125dBm >>MDS means -128dBm of noise in a CW (call it 300Hz) bandwidth, > >-125MDS means that noise is at -125dBm,not at -128dBm. >You feed a signal of a sig gen into the receiver and adjust >its level until a RMS AF voltmeter at the receiver's >AF output shows an increase of 3dB compared to no signal at input. >This means that signal and noise have the same level, hence >the increase of noise+signal by 3dB. >The dBm readout of the sig gen then is MDS. >ARRL use 500Hz as 'CW-BW'. >So noise figure is 21dB. >According to CCIR curves man made noise in a "quiet receiving >site" is 60dB. >Probably today even higher. >So there is plenty of room to shift the >transverter's/receiver's dynamic range up by additional input >attenuation >if it should be necessary to avoid 3rd order IM. >The front end topology can be found in the manual and is: >500kHz 7-pole LPF => 475kHz roofing filter with ceramic >elements => 5-pole 500kHz LPF => mixer > >>Could there have been something wrong with the test unit >>perhaps? > >...or with the test setup at such a low frequency? > >73 >Clemens >DL4RAJ > > > > >>-----Original Message----- >>From: owner-rsgb_lf_group@blacksheep.org >>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Andy Talbot >>Sent: Sunday, July 15, 2018 8:50 AM >>To: LineOne >>Subject: Re: LF: RE: Simple transverter for 472kHz >> >>Yes, I agree with your figures and they are terrible. -125dBm >>MDS means -128dBm of noise in a CW (call it 300Hz) bandwidth, >>that means a noise figure of around 21dB so there is no front >>end gain, and almost certainly some loss before mixer. >> >>So a -36dBm IP3 is appalling. The increases to -14dBm at >>75kHz just means there is some filtering in place. >> >>That low an IP3 is the sort of figure you'd expect, perhaps, >>from a single bipolar mixer; the sort of thing used in the >>1960s and 1970s (as I did in my first homebrew HF receiver !) >> >>Could there have been something wrong with the test unit >>perhaps? LO power drastically reduced into a mixer? It >>would be difficult to make a mixer with that low an IP3 othewise >> >> >>Andy >>www.g4jnt.com >> >> >> >>On 15 July 2018 at 00:54, jrusgrove@comcast.net >> wrote: >> >> >> Andy >> >> Maybe I can shed further light on my comments ... >> >> The ARRL receiver measurement system was developed by >>Wes Hayward of Tektronics back in the mid 70's and has been >>used with minor changes since. Instead of calculating 3IP the >>system quotes third order IMD dynamic range relative to the >>noise floor (MDS - minimum descernable signal). The MDS is >>deemed as the signal level at which a 3 dB increase over >>'background' noise is noted - as measured by an audio >>voltmeter. The measurement is normally made with the receiver >>in a cw bandwidth and is quoted in dBm. QST quotes the MDS for >>the this transverter as -125 dBm. For the two-tone IMD dynamic >>range measurement, two tones (at selected spacings) are >>injected into the receiver and the level is increased until >>the third order products are 3 dB above the background noise - >>at the MDS level. The two-tone dynamic range is the difference >>between MDS and the signal generator level. >> >> For this transverter with a -125 dBm MDS and 60 dB >>dynamic range at 2 kHz tone spacing, the indicated signal >>level to cause third order IMD products would be -65 dBm. At >>75 kHz spacing the signal level would be -51 dBm. Calculating >>IP3 for 2 kHz spacing using -125 dBm and -65 dBm produces an >>IP3 of -35 dBm. Calculating IP3 for 75 kHz spacing using -125 >>dBm and -51 dBm produces an IP3 of -14 dBm. >> >> I normally think in dynamic range numbers, not IP3, >>since I've been using the 'Hayward system' since the >>beginning. Since you think in IP3 numbers how do those IP3's >>look to you? >> >> Jay W1VD WD2XNS WE2XGR/2 >> >> >> >> ----- Original Message ----- >> From: Andy Talbot >> Reply-To: >> To: LineOne >> Sent: 7/14/2018 7:38:16 AM >> Subject: Re: LF: RE: Simple transverter for 472kHz >>________________________________ >> >> Those IMD figures don't in themselves say >>enough to say whether it is good or bad. >> >> Firstly, that quoted paragraph doesn't give the >>input levels at which IMPs were 60 [75dB] down. It is more >>usual to give a third order intercept point (TOIP)when >>specifiying linearity; a figure quoted in dBm >> >> Secondly, specifying IMPs at different >>bandwidths is meaningless too, as there is no indication of >>the receiver filtering. >> >> So all in all, rejecting that receive converter >>based on that quoted paragraph is going too far. >> >> If a level-7 (+7dBm Local Oscillator) diode >>ring mixer were to be used at the front end, with no preceding >>preamp and minimal loss filtering, you might reasonably expect >>a TOIP in the +15 to +20dBm region. That means IM Products >>will be, (in dB below theinput) twice the amount the RF input >>is below the TOIP. An example : >> >> TOIP = +20dBm >> Two tone input at a level of -20dBm >> IMPS = +20dBm - 2 * (+20dBm - -20dBm = >>-60dBc on the input signals. Or equivalent to -80dBm >> >> So two -20dBm signal into a typical 7dBm LO >>diode ring mixer give -60dBc third order products. >> A diode ring is what any self respecting >>designer might use on a basic LF receiver converter >> >> A level 13 mixer (+13dBm) wpouild give a >>proprtionately higher TOIP, perhaps +25 to +30dBm >> For higher linearity / better strong signal >>handling still, a bus-switch mixer offers a TOIP perhaps +35 >>to +45dBm. Like the Softrock receivers >> >> >> >> Andy >> www.g4jnt.com >> >> >> >> On 14 July 2018 at 12:13, N1BUG wrote: >> >> >> Ouch! Having operated on 160m and the >>HF bands for several years >> using a receiver that comes in at about >>-63 dB on 2 kHz spacing >> third-order IMD I would never again buy >>something with that kind of >> receiver "performance". >> >> Paul N1BUG >> >> >> On 07/06/2018 09:45 PM, >>jrusgrove@comcast.net wrote: >> > Saw the writeup in QST and >>immediately noticed the receive >> > two-tone, third-order IMD at 2 kHz >>spacing is 60 dB and at 75 kHz >> > spacing is only 74 dB! Good luck with >>that if you've got strong >> > signals at your location. >> > >> > Jay W1VD WD2XNS WE2XGR/2 >> >> >> >> >> >> >> >>=link&utm_campaign=sig-email&utm_content=emailclient> >Virenfrei. >www.avg.com >>=link&utm_campaign=sig-email&utm_content=emailclient> >> >> > > > >--- >Diese E-Mail wurde von AVG auf Viren geprüft. >http://www.avg.com >