Definitely worth checking into, tom. Thanks! Tom Behler: KB8TYJ -----Original Message----- From: For blind ham radio operators [mailto:[log in to unmask]] On Behalf Of Tom Fowle Sent: Sunday, February 21, 2016 9:39 PM To: [log in to unmask] Subject: Re: Next RFI Update, and question for Tom: WA6IVG tom, Just did a quick search for common mode chokes and saw this series from Palomar engineers. Not a reccommendation, just an example. Not as expensive as I'd thought. http://palomar-engineers.com/antenna-products/1-1-balun-kits tom Fowle WA6IVG On Sun, Feb 21, 2016 at 06:25:15PM -0800, Tom Fowle wrote: > tom, > Remember this gizmo is just a hypothesis based on guess work? > > When you can get to putting common mode chokes on your feed lines, you > have the choice of making them from turns of coax if you have extra > length of cable or of putting on a bunch of appropriate ferrite beads > over the feedline near the antenna. The beads are more expensive but > if you don't have extra feedline maybe easier to accomplish. > Suppliers of antenna accessories should be able to help you find the > correct ferrites for your feedline. > > Nothing from my friend yet. I'm not mentioning his name with out his > sayso since he's not a ham. > > good luck > Tom Fowle WA6IVG > > On Sun, Feb 21, 2016 at 12:09:44PM -0500, Tom Behler wrote: > > Tom: > > > > Thanks for the clarification. ... It helps a lot. > > > > I don't know if I'll get to it today, but this is certainly worth a try. > > > > If you get any thoughts from your engineer friend, please pass them along. > > > > If you want to write to me privately, my address is: > > > > [log in to unmask] > > > > > > Tom Behler: KB8TYJ > > > > > > -----Original Message----- > > From: For blind ham radio operators > > [mailto:[log in to unmask]] > > On Behalf Of Tom Fowle > > Sent: Saturday, February 20, 2016 11:52 PM > > To: [log in to unmask] > > Subject: Re: Next RFI Update, and question for Tom: WA6IVG > > > > tom, > > My thought is this thing would replace the ground wire from the > > common shack point or the outside ground point on your window panel, > > going to the ground rod. > > > > If I were going to mess with this, and it is purely hypothesis, I'd > > make the common mode chokes maybe 8 turns on a 6 or 8 inch diameter form. > > > > At the ground rod end, I'd connect the center and shield together > > and to the ground rod. > > At the top, just the center conductor to the ground on your window panel. > > > > Again this is perhaps nonsense. purely hypothetical, my vague theory > > is the chokes would keep common mode current off the outside of this > > new type of "shielded ground" > > > > > > I'd much rather see you put common mode chokes in the feeds near > > your actual antennas, but understand the weather makes that difficult. > > > > Gaads Tom, you might just have to turn off the "boots" <HORRORS!> > > > > I've written to my engineer friend discribing the aforementioned > > shielded ground, we'll see if he has anyting to say. > > Tom Fowle WA6IVG > > > > > > On Sat, Feb 20, 2016 at 11:30:06PM -0500, Tom Behler wrote: > > > This is a multipart message in MIME format. > > > > > > ------=_NextPart_000_0001_01D16C36.A1ED6AE0 > > > Content-Type: text/plain; > > > charset="us-ascii" > > > Content-Transfer-Encoding: 7bit > > > > > > Hi, all. > > > > > > > > > > > > I thoroughly checked all of my coax jumpers in the shack for > > > continuity, and all looked good. But, RFI issues still occurred. > > > > > > > > > > > > I then found a few small RG9913 jumpers I had lying around, and > > > actually had two snap-on RF chokes that could accommodate that > > > size of coax. Put one at the output of the TS590, and the other > > > between the output of my MFJ998 auto-tuner, and the common > > > connector on my six-position Alpha Delta antenna switch. Still no joy. > > > > > > > > > > > > Now, I have a question for Tom: (WA6IVG): > > > > > > > > > > > > In your last post with the subject of "shielded ground", you posed > > > a possible solution for an in-the-shack common ground. You said: > > > > > > > > > > > > How about a piece of coax as ground wire with center conductors > > > used as the actual ground. > > > > > > Now take the coax and wind a common mode choke in it at each end, > > > but do nothing with the shield at the top and ground the shield at > > > the > > bottom." > > > > > > > > > > > > I'm a bit confused: where exactly would you connect both ends of > > > this new grounding cable made out of coax? Obviously, one end > > > would go to the common ground connection on my feed-through panel, > > > but I'm not sure where the other end would go. Also, how would > > > you ground the shield at the other end of the cable? And, what > > > would you recommend for the size of the common mode chokes on each end? > > > > > > > > > > > > I have some extra coax here that I'd be willing to try this with > > > sometime tomorrow. > > > > > > > > > > > > Tom Behler: KB8TYJ > > > > > > > > > > > > > > > > > > > > > > > > > > > ------=_NextPart_000_0001_01D16C36.A1ED6AE0 > > > Content-Type: text/html; > > > charset="us-ascii" > > > Content-Transfer-Encoding: quoted-printable > > > > > > <html xmlns:v=3D"urn:schemas-microsoft-com:vml" = > > > xmlns:o=3D"urn:schemas-microsoft-com:office:office" = > > > xmlns:w=3D"urn:schemas-microsoft-com:office:word" = > > > xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" = > > > xmlns=3D"http://www.w3.org/TR/REC-html40"><head><meta = > > > http-equiv=3DContent-Type content=3D"text/html; = > > > charset=3Dus-ascii"><meta name=3DGenerator content=3D"Microsoft > > > Word > > > 14 = (filtered medium)"><style><!-- > > > /* Font Definitions */ > > > @font-face > > > {font-family:Calibri; > > > panose-1:2 15 5 2 2 2 4 3 2 4;} > > > /* Style Definitions */ > > > p.MsoNormal, li.MsoNormal, div.MsoNormal > > > {margin:0in; > > > margin-bottom:.0001pt; > > > font-size:11.0pt; > > > font-family:"Calibri","sans-serif";} > > > a:link, span.MsoHyperlink > > > {mso-style-priority:99; > > > color:blue; > > > text-decoration:underline;} > > > a:visited, span.MsoHyperlinkFollowed > > > {mso-style-priority:99; > > > color:purple; > > > text-decoration:underline;} > > > p.MsoPlainText, li.MsoPlainText, div.MsoPlainText > > > {mso-style-priority:99; > > > mso-style-link:"Plain Text Char"; > > > margin:0in; > > > margin-bottom:.0001pt; > > > font-size:11.0pt; > > > font-family:"Calibri","sans-serif";} > > > span.EmailStyle17 > > > {mso-style-type:personal-compose; > > > font-family:"Calibri","sans-serif"; > > > color:windowtext;} > > > span.PlainTextChar > > > {mso-style-name:"Plain Text Char"; > > > mso-style-priority:99; > > > mso-style-link:"Plain Text"; > > > font-family:"Calibri","sans-serif";} > > > .MsoChpDefault > > > {mso-style-type:export-only; > > > font-family:"Calibri","sans-serif";} > > > @page WordSection1 > > > {size:8.5in 11.0in; > > > margin:1.0in 1.0in 1.0in 1.0in;} > > > div.WordSection1 > > > {page:WordSection1;} > > > --></style><!--[if gte mso 9]><xml> > > > <o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" /> > > > </xml><![endif]--><!--[if gte mso 9]><xml> <o:shapelayout > > > v:ext=3D"edit"> <o:idmap v:ext=3D"edit" data=3D"1" /> > > > </o:shapelayout></xml><![endif]--></head><body lang=3DEN-US > > > link=3Dblue = vlink=3Dpurple><div class=3DWordSection1><p > > > class=3DMsoNormal>Hi, = all.<o:p></o:p></p><p > > > class=3DMsoNormal><o:p> </o:p></p><p = class=3DMsoNormal>I > > > thoroughly checked all of my coax jumpers in the = shack for > > > continuity, and all looked good. But, RFI issues still = > > > occurred.<o:p></o:p></p><p > > > class=3DMsoNormal><o:p> </o:p></p><p = class=3DMsoNormal>I > > > then found a few small RG9913 jumpers I had lying = around, and > > > actually had two snap-on RF chokes that could accommodate = that > > > size of coax. Put one at the output of the TS590, and the = > > > other between the output of my MFJ998 auto-tuner, and the > > > common = connector on my six-position Alpha Delta antenna > > > switch. Still no = joy.<o:p></o:p></p><p > > > class=3DMsoNormal><o:p> </o:p></p><p = class=3DMsoNormal>Now, > > > I have a question for Tom: = (WA6IVG):<o:p></o:p></p><p > > > class=3DMsoNormal><o:p> </o:p></p><p = class=3DMsoNormal>In > > > your last post with the subject of “shielded = > > > ground”, you posed a possible solution for an in-the-shack > > > common = ground. You said:<o:p></o:p></p><p = > > > class=3DMsoNormal><o:p> </o:p></p><p > > > class=3DMsoPlainText>How about = a piece of coax as ground wire > > > with center conductors used as the actual = ground. > > > <o:p></o:p></p><p class=3DMsoPlainText>Now take the coax and = > > > wind a common mode choke in it at each end, but do nothing with > > > the = shield at the top and ground the shield at the = > > > bottom.”<o:p></o:p></p><p = > > > class=3DMsoPlainText><o:p> </o:p></p><p = > > > class=3DMsoPlainText>I’m a bit confused: where exactly > > > would = you connect both ends of this new grounding cable made out > > > of = coax? Obviously, one end would go to the common ground > > > connection = on my feed-through panel, but I’m not sure > > > where the other end = would go. Also, how would you ground > > > the shield at the other end = of the cable? And, what would > > > you recommend for the size of the = common mode chokes on each > > > end?<o:p></o:p></p><p = > > > class=3DMsoPlainText><o:p> </o:p></p><p > > > class=3DMsoPlainText>I have = some extra coax here that I’d > > > be willing to try this with sometime = tomorrow.<o:p></o:p></p><p > > > class=3DMsoPlainText><o:p> </o:p></p><p = > > > class=3DMsoPlainText>Tom Behler: KB8TYJ<o:p></o:p></p><p = > > > class=3DMsoPlainText><o:p> </o:p></p><p = > > > class=3DMsoPlainText><o:p> </o:p></p><p = > > > class=3DMsoNormal><o:p> </o:p></p></div></body></html> > > > ------=_NextPart_000_0001_01D16C36.A1ED6AE0--