KPA100 SO-239 Help
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Mine was the same way. No worries, it will be fine. 73, David AJ4TF > > ------------------------------ > > Message: 13 > Date: Thu, 24 Feb 2011 14:18:11 -0600 > From: "John Cooper" <[hidden email]> > Subject: [Elecraft] KPA100 SO-239 Help > To: "elecraft" <[hidden email]> > Message-ID: <2B954EFE7E5E49CCB2319FF78C6FE878@WT5YPC> > Content-Type: text/plain; charset="iso-8859-1" > > Ive installed J2 (so-239 antenna connector) on the rear panel of the kpa100 and soldered the red and black jumper wires along with the component lead. After I noticed the inside connector and the red dialectric foam spins freely inside of the outer threaded shell of the connector. Is this ok or do I need to replace this so-239? > > John WT5Y > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Hi John,
If it were me, and there is a possibility that the inner wire soldered to the inner pin could freely spin around during the process of taking on/off coax at the back of the unit, I would not take the risk of compromising the inner wire such that it could twist, bird-cage or possibly short to gnd. N1BBR -- [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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I've found the same problem with two batches of Teflon insulated, single
hole mount SO-239 connectors manufactured in China and purchased from RF Connection. The center pin spins within the Teflon bushing and unless the user is extremely careful when connecting a PL-259, the wire connected to the center conductor will break off. I returned one batch and received a second batch that were supposed to be correct and found the same problem. I rejected those as well. I agree that a connector with this problem should not be used - too great a risk of damage to the internal wiring. Jack K8ZOA On 2/25/2011 12:58 PM, dw wrote: > Hi John, > If it were me, and there is a possibility that the inner wire soldered > to the inner pin could freely spin around during the process of taking > on/off coax at the back of the unit, I would not take the risk of > compromising the inner wire such that it could twist, bird-cage or > possibly short to gnd. > > N1BBR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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He is talking about prior to soldering. I have seen these too. So has
HRO who had to send a bunch back for just this reason. On 2/25/2011 11:38 AM, Ron D'Eau Claire wrote: > An SO/PL239 is pushed on, not twisted, until the face of the male is against > the ridged edge of the female, then the outer shell is threaded on and > tightened. The center pin never turns nor has any torque applied. > > I cannot picture how you could "spin" the CENTER conductor. That would > require twisting the coax attached to the male half. > > Ron AC7AC > > -----Original Message----- > I've found the same problem with two batches of Teflon insulated, single > hole mount SO-239 connectors manufactured in China and purchased from RF > Connection. The center pin spins within the Teflon bushing and unless > the user is extremely careful when connecting a PL-259, the wire > connected to the center conductor will break off. > > I returned one batch and received a second batch that were supposed to > be correct and found the same problem. I rejected those as well. > > I agree that a connector with this problem should not be used - too > great a risk of damage to the internal wiring. > > Jack K8ZOA > > On 2/25/2011 12:58 PM, dw wrote: >> Hi John, >> If it were me, and there is a possibility that the inner wire soldered >> to the inner pin could freely spin around during the process of taking >> on/off coax at the back of the unit, I would not take the risk of >> compromising the inner wire such that it could twist, bird-cage or >> possibly short to gnd. >> >> N1BBR > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Jack Smith-6
One solution, especially for folks who are in the beginning stages of K3
construction, involves substitution of the SO-239 for a better quality connector. I used a pair of Amphenol types with a Teflon insulator, but Phenolic is fine. These were purchased from Mouser, catalog P/N is 523-83-798. The Amphenol P/N is 83-798. On a related matter, I avoid RF return path connections where only the chassis is used to establish an RF return without a dedicated return wire. Without a return wire, the return path is often left to force its way through multiple mating metal pieces and hardware. On my K3, I added a dedicated ground lug and buss wire connected to the SO-239's machine screws. The other ends are connected back to the PCB, adjacent to the center pin wire. On a different mail list, this sparked debate as to whether this practice creates a "PIN 1" problem. It doesn't. The buss wire is used back to the RF circuit but it's not a substitute for the SO-239 bonding still desired at the chassis. What's odd is that the KPA100 assembly manual as shown on p.32 (Figure A2) shows use of a ground lug and buss wire on the SO-239 connector back to circuit ground. The oddity is that this practice was not carried through on the K3. Apart from the chassis, it seems the only ground return connection available on or near the SO-239 is if the Aux RF BNC connector is installed. Then, the shield of the RG-174 coax ties to a ground lug. For reference, see p. 24 of the K3 assembly manual. Paul, W9AC ----- Original Message ----- From: "Jack Smith" <[hidden email]> To: <[hidden email]> Sent: Friday, February 25, 2011 1:08 PM Subject: Re: [Elecraft] KPA100 SO-239 Help > I've found the same problem with two batches of Teflon insulated, single > hole mount SO-239 connectors manufactured in China and purchased from RF > Connection. The center pin spins within the Teflon bushing and unless > the user is extremely careful when connecting a PL-259, the wire > connected to the center conductor will break off. > > I returned one batch and received a second batch that were supposed to > be correct and found the same problem. I rejected those as well. > > I agree that a connector with this problem should not be used - too > great a risk of damage to the internal wiring. > > Jack K8ZOA > > On 2/25/2011 12:58 PM, dw wrote: >> Hi John, >> If it were me, and there is a possibility that the inner wire soldered >> to the inner pin could freely spin around during the process of taking >> on/off coax at the back of the unit, I would not take the risk of >> compromising the inner wire such that it could twist, bird-cage or >> possibly short to gnd. >> >> N1BBR > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by AC7AC
> I cannot picture how you could "spin" the CENTER conductor. That would
> require twisting the coax attached to the male half. Sure, it shouldn't happen if the op uses diligence in keeping all connectors tight. But if the PL-259 becomes loose and ever-so-slightly unmates from the SO-239, the retention "teeth" no longer inhibit connector rotation. Any lateral pressure from the cable, especially from large, inflexible cables, causes the SO-239 pin to rotate. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by P.B. Christensen
> One solution, especially for folks who are in the beginning stages of K3
> construction, involves Sorry, meant KPA100 or K3 construction... Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by w0mu
It's easy enough to inadvertently to rotate the center pin when mating
with the PL-259 particularly with small diameter coax cable and where the connector is not the easiest to access. Push the center pin in, and then find the coax isn't routed exactly like it should be, move the cable around and then push the shell into place. This is more of an issue with adapters, BNC(F) to UHF(M) for example, where it isn't uncommon to rely upon the center pin to hold the adapter in place while getting the shell started. And some of the cheap imported adapters have poor shell threads to begin with which makes it more likely to spin the center pin. Depending on how much slack is on the other end, it's possible to break the connection. I had a couple of special order amplifiers with these connectors that had exactly this failure mode. Wound up using flange mount UHF connectors to avoid the problem, although the single hole connectors are mechanically neater. Mouser stocks a single hole UHF connector that doesn't have this problem, but it ships without a hex nut, lockwasher and ground tab washer. The hex nut costs more than the connector. Jack K8ZOA On 2/25/2011 1:47 PM, Mike Fatchett W0MU wrote: > He is talking about prior to soldering. I have seen these too. So has > HRO who had to send a bunch back for just this reason. > > On 2/25/2011 11:38 AM, Ron D'Eau Claire wrote: >> An SO/PL239 is pushed on, not twisted, until the face of the male is against >> the ridged edge of the female, then the outer shell is threaded on and >> tightened. The center pin never turns nor has any torque applied. >> >> I cannot picture how you could "spin" the CENTER conductor. That would >> require twisting the coax attached to the male half. >> >> Ron AC7AC >> >> -----Original Message----- >> I've found the same problem with two batches of Teflon insulated, single >> hole mount SO-239 connectors manufactured in China and purchased from RF >> Connection. The center pin spins within the Teflon bushing and unless >> the user is extremely careful when connecting a PL-259, the wire >> connected to the center conductor will break off. >> >> I returned one batch and received a second batch that were supposed to >> be correct and found the same problem. I rejected those as well. >> >> I agree that a connector with this problem should not be used - too >> great a risk of damage to the internal wiring. >> >> Jack K8ZOA >> >> On 2/25/2011 12:58 PM, dw wrote: >>> Hi John, >>> If it were me, and there is a possibility that the inner wire soldered >>> to the inner pin could freely spin around during the process of taking >>> on/off coax at the back of the unit, I would not take the risk of >>> compromising the inner wire such that it could twist, bird-cage or >>> possibly short to gnd. >>> >>> N1BBR >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by aj4tf
Perhaps a Little super glue would keep it from spinning. Geo/W2BPI
______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by w0mu
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In reply to this post by P.B. Christensen
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In reply to this post by P.B. Christensen
All good stuff. My K3 exhibits erratic power output at times, (TX Gain failure) corrected by loosening and retightening the screw that threads into the 2D block and standoff next to the SO-239. Relying on aluminum-to-aluminum mechanical connections for r-f returns is bad business.
Next time I'm in the mood I will apply Paul's fix. Wes N7WS --- On Fri, 2/25/11, Paul Christensen <[hidden email]> wrote: > From: Paul Christensen <[hidden email]> > Subject: Re: [Elecraft] KPA100 SO-239 Help > To: [hidden email] > Date: Friday, February 25, 2011, 11:48 AM > One solution, especially for folks > who are in the beginning stages of K3 > construction, involves substitution of the SO-239 for a > better quality > connector. I used a pair of Amphenol types with a > Teflon insulator, but > Phenolic is fine. These were purchased from Mouser, > catalog P/N is > 523-83-798. The Amphenol P/N is 83-798. > > On a related matter, I avoid RF return path > connections where only the > chassis is used to establish an RF return without a > dedicated return wire. > Without a return wire, the return path is often left to > force its way > through multiple mating metal pieces and hardware. On > my K3, I added a > dedicated ground lug and buss wire connected to the > SO-239's machine screws. > The other ends are connected back to the PCB, adjacent to > the center pin > wire. On a different mail list, this sparked debate as to > whether this > practice creates a "PIN 1" problem. It doesn't. > The buss wire is used back > to the RF circuit but it's not a substitute for the SO-239 > bonding still > desired at the chassis. > > What's odd is that the KPA100 assembly manual as shown on > p.32 (Figure A2) > shows use of a ground lug and buss wire on the SO-239 > connector back to > circuit ground. The oddity is that this practice was > not carried through on > the K3. Apart from the chassis, it seems > the only ground return connection > available on or near the SO-239 is if the Aux RF BNC > connector is > installed. Then, the shield of the RG-174 coax ties > to a ground lug. For > reference, see p. 24 of the K3 assembly manual. > > Paul, W9AC > > ----- Original Message ----- > From: "Jack Smith" <[hidden email]> > To: <[hidden email]> > Sent: Friday, February 25, 2011 1:08 PM > Subject: Re: [Elecraft] KPA100 SO-239 Help > > > > I've found the same problem with two batches of Teflon > insulated, single > > hole mount SO-239 connectors manufactured in China and > purchased from RF > > Connection. The center pin spins within the Teflon > bushing and unless > > the user is extremely careful when connecting a > PL-259, the wire > > connected to the center conductor will break off. > > > > I returned one batch and received a second batch that > were supposed to > > be correct and found the same problem. I rejected > those as well. > > > > I agree that a connector with this problem should not > be used - too > > great a risk of damage to the internal wiring. > > > > Jack K8ZOA > > > > On 2/25/2011 12:58 PM, dw wrote: > >> Hi John, > >> If it were me, and there is a possibility that the > inner wire soldered > >> to the inner pin could freely spin around during > the process of taking > >> on/off coax at the back of the unit, I would not > take the risk of > >> compromising the inner wire such that it could > twist, bird-cage or > >> possibly short to gnd. > >> > >> N1BBR > > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by dw-4
dw,
No worries -- There are two wires connected to the inside of the KPA100 SO-239. Yes, one goes straight out the back of the center pin, but the other is soldered at right angles to it - the wire soldered at right angles will stabilize any tendency for the center pin to turn after it is soldered.. I have seen and used many SO-239 connectors with a center pin that will rotate. This is not a problem under normal conditions. One simply slides the center pin of the PL-259 in, but does not turn the coax more than 1/8 turn in the process. Yes, the shield connection is turned to tighten the connector, but not the center conductor. 73, Don W3FPR On 2/25/2011 12:58 PM, dw wrote: > Hi John, > If it were me, and there is a possibility that the inner wire soldered > to the inner pin could freely spin around during the process of taking > on/off coax at the back of the unit, I would not take the risk of > compromising the inner wire such that it could twist, bird-cage or > possibly short to gnd. > > N1BBR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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