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Date: Thu, 1 Dec 2022 21:32:45 -0600 In-Reply-To: <20221201.202220.8436.0@webmail04.vgs.untd.com> Cc: OFARC <ofarc@mailman.qth.net> To: Dominic Mazoch <domemt@juno.com> References: <20221201.202220.8436.0@webmail04.vgs.untd.com> X-Mailer: Apple Mail (2.3731.200.110.1.12) X-UNTD-BPF: 47307d41197d15403915b539b5457434792571191414c1b9d9a134f5a10dbd0d9d4dd5444d44b9e9a595951064d5e090e591e5a5649d38e005a100d51400cd61f9fdf9242d50d0d0d0b1a4b4 X-UNTD-BodySize: 4327 X-UNTD-SPF: Pass X-UNTD-DKIM: PASS X-ContentStamp: 1:1:1799545703 X-MAIL-INFO: 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 656079b9050dc14da984cdd55129d5ad X-UNTD-Peer-Info: 209.85.210.45|mail-ot1-f45.google.com|mail-ot1-f45.google.com|ursae47@gmail.com X-UNTD-UBE: -1 --Apple-Mail=_6690C619-FFF1-4330-8254-796BDA812180 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Hey Dom, Good evening. In my understanding of this, the unun is an unbalanced to = unbalanced transformer which uses an inductor and as such, together with = stray capacitance, will act as a filter of specific frequency ranges. =20= So it is possible that the suppressed QRM frequencies that you mentioned = , populated a particular frequency range and that range was =E2=80=9Ccutof= f" by the unun. In other words, it=E2=80=99s entirely possible that the = filtering action inherent in the unun was indeed cutting off your QRM. It would be interesting to delve into this idea, and quantify it, by = using a spectrum analyzer such as the TinySA Spectrum Analyzer = <https://www.amazon.com/Upgraded-Karagas-0-1MHZ-350MHZ-240MHZ-960MHZ-Frequ= ency/dp/B08C8RNX17/ref=3Dasc_df_B08C8RNX17?tag=3Dbngsmtphsnus-20&linkCode=3D= df0&hvadid=3D80127030278136&hvnetw=3Ds&hvqmt=3De&hvbmt=3Dbe&hvdev=3Dc&hvlo= cint=3D&hvlocphy=3D&hvtargid=3Dpla-4583726556022657&psc=3D1>. One could = then use it for an "A/B test" with and without the 1:1 unun.=20 Just my 2 cents. Regards & 73, Stephen (W2WF) =20 > On Dec 1, 2022, at 8:22 PM, Dominic Mazoch <domemt@juno.com> wrote: >=20 > I just put a 1:1 unun in my coax. Seems it cuts out some QRM. Is = there something I am not hearing? >=20 >=20 > Dominic Mazoch > ______________________________________________________________ > OFARC mailing list > Home: http://mailman.qth.net/mailman/listinfo/ofarc > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:OFARC@mailman.qth.net >=20 > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to ursae47@gmail.com --Apple-Mail=_6690C619-FFF1-4330-8254-796BDA812180 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 <html><head><meta http-equiv=3D"content-type" content=3D"text/html; = charset=3Dutf-8"></head><body style=3D"overflow-wrap: break-word; = -webkit-nbsp-mode: space; line-break: after-white-space;">Hey = Dom,<div>Good evening. &nbsp;In my understanding of this, the unun is an = unbalanced to unbalanced transformer which uses an inductor and as such, = together with stray capacitance, will act as a filter of specific = frequency ranges. &nbsp;</div><div><br></div><div>So it is possible that = the suppressed QRM frequencies that you mentioned , populated a = particular frequency range and that range was =E2=80=9Ccutoff" by the = unun. &nbsp;In other words, it=E2=80=99s entirely possible that the = filtering action inherent in the unun was indeed cutting off your = QRM.</div><div><br></div><div>It would be interesting to delve into this = idea, and quantify it, by using a spectrum analyzer such as the <a = href=3D"https://www.amazon.com/Upgraded-Karagas-0-1MHZ-350MHZ-240MHZ-960MH= Z-Frequency/dp/B08C8RNX17/ref=3Dasc_df_B08C8RNX17?tag=3Dbngsmtphsnus-20&am= p;linkCode=3Ddf0&amp;hvadid=3D80127030278136&amp;hvnetw=3Ds&amp;hvqmt=3De&= amp;hvbmt=3Dbe&amp;hvdev=3Dc&amp;hvlocint=3D&amp;hvlocphy=3D&amp;hvtargid=3D= pla-4583726556022657&amp;psc=3D1">TinySA Spectrum Analyzer</a>. = &nbsp;One could then use it for an "A/B test" with <u>and</u> without = the 1:1 unun.&nbsp;</div><div><br></div><div>Just my 2 = cents.</div><div><br></div><div>Regards &amp; 73,</div><div>Stephen = (W2WF)</div><div><br></div><div><br></div><div>&nbsp;<br><div><br><blockqu= ote type=3D"cite"><div>On Dec 1, 2022, at 8:22 PM, Dominic Mazoch = &lt;domemt@juno.com&gt; wrote:</div><br = class=3D"Apple-interchange-newline"><div><div>I just put a 1:1 unun in = my coax. &nbsp;Seems it cuts out some QRM. &nbsp;Is there something I am = not hearing?<br><br><br>Dominic = Mazoch<br>______________________________________________________________<b= r>OFARC mailing list<br>Home: = http://mailman.qth.net/mailman/listinfo/ofarc<br>Help: = http://mailman.qth.net/mmfaq.htm<br>Post: = mailto:OFARC@mailman.qth.net<br><br>This list hosted by: = http://www.qsl.net<br>Please help support this email list: = http://www.qsl.net/donate.html<br>Message delivered to = ursae47@gmail.com<br></div></div></blockquote></div><br></div></body></htm= l>= --Apple-Mail=_6690C619-FFF1-4330-8254-796BDA812180-- ]