Re: [Elecraft] loss of RX sensitivity
Lets close this thread - we are -way- past the max posting number limit for a single topic. Folks - I am not always able to watch the list in real time. Please self limit on OT discussions like this. Once you hit 5-10 emails (at most) please take it off list. You do not need to wait for me to step in. :-) 73, Eric List moderator, from time to time..) /elecraft.com/ On 9/19/2018 9:12 AM, Dave B via Elecraft wrote: No, BNC's and N's do not inter-mate, not without damage. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
No, BNC's and N's do not inter-mate, not without damage. Yes, you can push a N plug into a BNC socket, but the BNC socket will be permanently damaged if you push hard enough for it not to fall out unexpectedly. Plus the mismatch will be bad. But in an emergency? Yes, the dimensions of the actual RF connector interface are similar, but there is a major difference in the dielectric arrangements. N's are "weather resistant" (some more so than others) but not "water proof". BNC's of course are neither. (And neither are SO239/PL259's!) 73. Dave G0WBX. On 19/09/18 15:24, hawley, charles j jr wrote: > As I remember, the bnc and n actually plug together. What then is the benefit > of n? Water resistance? > > Chuck Jack > KE9UW > > Sent from my iPhone, cjack __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
> On Sep 19, 2018, at 7:24 AM, hawley, charles j jr > wrote: > > As I remember, the bnc and n actually plug together. What then is the benefit > of n? Water resistance? > > Chuck Jack > KE9UW Type N is weatherproof, BNC is not. Type N peak voltage is 1500 V, BNC is 500 V (UHF is also 500 V). Type N rated to 11 GHz, BNC to 4 GHz. Type N RF leakage -90 dB min @ 3 GHz, BNC -55 dB min @ 3GHz. For this kind of thing, I go to the Amphenol spec sheets for connectors. The specs for the UHF connector are minimal, three specs for electrical, no mil specs. https://www.amphenolrf.com/connectors/bnc.html https://www.amphenolrf.com/connectors/n-type.html https://www.amphenolrf.com/connectors/uhf.html wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
As I remember, the bnc and n actually plug together. What then is the benefit of n? Water resistance? Chuck Jack KE9UW Sent from my iPhone, cjack > On Sep 19, 2018, at 7:28 AM, Dave B via Elecraft > wrote: > > Hi Jim. > > Mostly, N connectors, BNC's, TNC's, SC and 7-16's. And for the big > stuff, EIA flange connectors. Plus some other weird stuff. (3 lug > BNC's and such, to prevent the "wrong connection".)The odd > appearance of the C connector on some US kit too. Some "Spinner" 'BN' > series connectors to, also often seen in the European Broadcast industry > and some military. > > A lot of US equipment also still use the various unique to the US > connectors, often seen on big Bird loads etc. Not so common over hear. > > That based on what I've seen on kit "being tested" at customers sites > over the last 28 years. > > The only UHF series connector commercially used, that I've personally > seen in that time frame is on a very old design of screened room weld > crack detector, and it's a nightmare to use as it's always working loose. > > To Charlie. > > The threads have no part to play in the RF path on a UHF connector, it's > all down to the two outer mating faces being pressed together. The > older (so called) MIL spec types, that had all the castelations at that > point were *MUCH* better because of it, as they sort of interlocked and > made a much better contact due to the metal to metal force > multiplication that results.. They also tended not to rotate relative > to each other so the retaining ring stayed tight. Basic mechanical > design feature, missing on the modern versions, where the two parts can > rotate, even when the ring is (allegedly) tight. > > The modern stuff with the 4 slots on the socket, and two bumps on the > plug, are just utter crap. (Built down to a cost.) > > I'm amazed that no maker has innovated gone back to the original design, > and fitted a crinkle spring washer behind the locking ring, so that > contact pressure can be maintained, and also helping to keep the threads > from working loose when subject to vibration... > > But even then, they'd still only be of any practical use below 100MHz > due to the impedance mismatch issue. (Originally for use below 30MHz.) > > https://en.wikipedia.org/wiki/UHF_connector > > Stick with BNC's, N's and if you have too, 7-16's. They are all easy to > fit to cable with practice, no special tools needed unless you insist on > the crimp types, and then you *MUST* have the correct tooling for that > particular make of connector. > > The pressure gland fitting types, are also easy to remove, clean up and > re-fit if a cable becomes damaged. > > All it takes is some practice. Buy some surplus ex-military patch > leads, and practice removing and refitting them. After a few of each it > becomes very easy. > > 73. > >Dave G0WBX. > > >> On 19/09/18 12:15, Jim Miller wrote: >> Hi Dave >> >> What does NATO use in place of pl259? >> >> Thanks! >> >> Jim ab3cv >> >> On Sep 19, 2018, at 4:16 AM, Dave B via Elecraft >> wrote: >> >> Wunder, I'll second you on that! >> >> Of all the 1000's of RF connectors I've assembled and used over the >> years for my own hobby and at work. The venerable "UHF" series have >> always proved to be the nastiest most unreliable types ever. Period. >> >> All my own personal radio kit, either get's them replaced (Sadly, not >> always an easy job) with a N or BNC (in one case, a TNC.) Or a BNC (or >> N) adapter is securely fitted as a permanent fixture (including LocTite >> on the threads, in mobile/portable situations!) >> >> I also use BNC's at HF, as we do at work. They can happily carry well >> over 150W at up to 220MHz even in the presence of some very bad VSWR's >> (6:1 or higher.) Assemble them correctly and look after them >> physically, and they will last a lifetime. >> >> The UHF series are just plain unreliable. It is no surprise that the >> military (NATO) don't use them any more. >> >> 73. >> >> Dave G0WBX (also G8KBV) >> >> >> >>> On 18/09/18 19:45, elecraft-requ...@mailman.qth.net wrote: >>> Message: 1 >>> Date: Mon, 17 Sep 2018 16:45:10 -0700 >>> From: Walter Underwood >>> To: "elecraft@mailman.qth.net" >>> Subject: Re: [Elecraft] loss of RX sensitivity >>> Message-ID: >>> Content-Type: text/plain;charset=utf-8 >>>
Re: [Elecraft] loss of RX sensitivity
Hi Jim. Mostly, N connectors, BNC's, TNC's, SC and 7-16's. And for the big stuff, EIA flange connectors. Plus some other weird stuff. (3 lug BNC's and such, to prevent the "wrong connection".) The odd appearance of the C connector on some US kit too. Some "Spinner" 'BN' series connectors to, also often seen in the European Broadcast industry and some military. A lot of US equipment also still use the various unique to the US connectors, often seen on big Bird loads etc. Not so common over hear. That based on what I've seen on kit "being tested" at customers sites over the last 28 years. The only UHF series connector commercially used, that I've personally seen in that time frame is on a very old design of screened room weld crack detector, and it's a nightmare to use as it's always working loose. To Charlie. The threads have no part to play in the RF path on a UHF connector, it's all down to the two outer mating faces being pressed together. The older (so called) MIL spec types, that had all the castelations at that point were *MUCH* better because of it, as they sort of interlocked and made a much better contact due to the metal to metal force multiplication that results.. They also tended not to rotate relative to each other so the retaining ring stayed tight. Basic mechanical design feature, missing on the modern versions, where the two parts can rotate, even when the ring is (allegedly) tight. The modern stuff with the 4 slots on the socket, and two bumps on the plug, are just utter crap. (Built down to a cost.) I'm amazed that no maker has innovated gone back to the original design, and fitted a crinkle spring washer behind the locking ring, so that contact pressure can be maintained, and also helping to keep the threads from working loose when subject to vibration... But even then, they'd still only be of any practical use below 100MHz due to the impedance mismatch issue. (Originally for use below 30MHz.) https://en.wikipedia.org/wiki/UHF_connector Stick with BNC's, N's and if you have too, 7-16's. They are all easy to fit to cable with practice, no special tools needed unless you insist on the crimp types, and then you *MUST* have the correct tooling for that particular make of connector. The pressure gland fitting types, are also easy to remove, clean up and re-fit if a cable becomes damaged. All it takes is some practice. Buy some surplus ex-military patch leads, and practice removing and refitting them. After a few of each it becomes very easy. 73. Dave G0WBX. On 19/09/18 12:15, Jim Miller wrote: > Hi Dave > > What does NATO use in place of pl259? > > Thanks! > > Jim ab3cv > > On Sep 19, 2018, at 4:16 AM, Dave B via Elecraft > wrote: > > Wunder, I'll second you on that! > > Of all the 1000's of RF connectors I've assembled and used over the > years for my own hobby and at work. The venerable "UHF" series have > always proved to be the nastiest most unreliable types ever. Period. > > All my own personal radio kit, either get's them replaced (Sadly, not > always an easy job) with a N or BNC (in one case, a TNC.) Or a BNC (or > N) adapter is securely fitted as a permanent fixture (including LocTite > on the threads, in mobile/portable situations!) > > I also use BNC's at HF, as we do at work. They can happily carry well > over 150W at up to 220MHz even in the presence of some very bad VSWR's > (6:1 or higher.) Assemble them correctly and look after them > physically, and they will last a lifetime. > > The UHF series are just plain unreliable. It is no surprise that the > military (NATO) don't use them any more. > > 73. > > Dave G0WBX (also G8KBV) > > > >> On 18/09/18 19:45, elecraft-requ...@mailman.qth.net wrote: >> Message: 1 >> Date: Mon, 17 Sep 2018 16:45:10 -0700 >> From: Walter Underwood >> To: "elecraft@mailman.qth.net" >> Subject: Re: [Elecraft] loss of RX sensitivity >> Message-ID: >> Content-Type: text/plain;charset=utf-8 >> >> The next time someone challenges me on why I only use BNC and Type N >> connectors, I?m going to send them this entire discussion. >> >> wunder >> K6WRU >> Walter Underwood >> CM87wj >> http://observer.wunderwood.org/ (my blog) -- Created on and sent from a Unix like PC running and using free and open source software. :: __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Wunder, I'll second you on that! Of all the 1000's of RF connectors I've assembled and used over the years for my own hobby and at work. The venerable "UHF" series have always proved to be the nastiest most unreliable types ever. Period. All my own personal radio kit, either get's them replaced (Sadly, not always an easy job) with a N or BNC (in one case, a TNC.) Or a BNC (or N) adapter is securely fitted as a permanent fixture (including LocTite on the threads, in mobile/portable situations!) I also use BNC's at HF, as we do at work. They can happily carry well over 150W at up to 220MHz even in the presence of some very bad VSWR's (6:1 or higher.) Assemble them correctly and look after them physically, and they will last a lifetime. The UHF series are just plain unreliable. It is no surprise that the military (NATO) don't use them any more. 73. Dave G0WBX (also G8KBV) On 18/09/18 19:45, elecraft-requ...@mailman.qth.net wrote: > Message: 1 > Date: Mon, 17 Sep 2018 16:45:10 -0700 > From: Walter Underwood > To: "elecraft@mailman.qth.net" > Subject: Re: [Elecraft] loss of RX sensitivity > Message-ID: > Content-Type: text/plain; charset=utf-8 > > The next time someone challenges me on why I only use BNC and Type N > connectors, I?m going to send them this entire discussion. > > wunder > K6WRU > Walter Underwood > CM87wj > http://observer.wunderwood.org/ (my blog) -- Created on and sent from a Unix like PC running and using free and open source software. :: __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
I've worn a BNC out on a Tek scope once or twice in 35 years... Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles From: elecraft-boun...@mailman.qth.net [elecraft-boun...@mailman.qth.net] on behalf of Wes Stewart [wes_n...@triconet.org] Sent: Tuesday, September 18, 2018 12:51 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] loss of RX sensitivity It's difficult to argue with Frank's experience and expertise. That said, fools rush in... I own some network analyzers, 1) an N2PK which I built with type N connectors, 2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert AA-55 Zoom with a SO239. Professionally, I've used analyzers with type N, 3.5mm (beadless SMA) and K connectors. With the exception of the AA-55, which only goes to 55 MHz, all of these can be calibrated with "precision" calibration kits that can cost thousands of dollars. So far, Frank is right, not a BNC in the bunch. But that has changed with the introduction of the DG5MK's FA-VA5, one-port vector analyzer. I am on the reserve list to buy one of these. The thing to note is that it is supplied with a BNC connector. There has been a lot of anguish, heartburn, etc about this on the VNWA Yahoo group but the consensus is that it will be fine and BNC calibration kit has been developed and tested without issue. https://www.youtube.com/watch?v=X8Z7veGV57o There are tens of thousands of BNCs on oscilloscopes and other instruments and I've seldom had an issue with them in 30+ years of lab work. For quick disconnect I also use short jumper cables with BNCs to break the connections between the hardline running to the tower and the cable entrance to the shack during lightning season. Admittedly, I'm only running 500 W. When I can leave them more permanently connected I revert to type N. Wes N7WS __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Hi Frank, Agreed. See: https://www.sdr-kits.net/VA5_Page bottom of the page. Indicative prices in USD $191.77 Wes On 9/18/2018 1:53 PM, donov...@starpower.net wrote: Hi Wes, Thanks for forwarding the information about DG5MK's new FA-VA5 VNA. What is its current selling price? If you use many BNC connectors, you'll notice a distinct difference in connector quality especially above 100 MHz. Avoid using BNC male connectors with weak tension when you turn the bayonette to engage the connector. If the bayonette turns too easily it doesn't maintain sufficient engagement force to keep the RF connections in proper alignment. 73 Frank W3LPL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
https://www.eham.net/ehamforum/smf/index.php?topic=34680.0;wap2 Bob K3DJC On Tue, 18 Sep 2018 16:53:01 -0400 (EDT) donov...@starpower.net writes: > Hi Wes, > > > Thanks for forwarding the information about DG5MK's new FA-VA5 > VNA. What is its current selling price? > > > If you use many BNC connectors, you'll notice a distinct difference > in > connector quality especially above 100 MHz. Avoid using BNC male > connectors with weak tension when you turn the bayonette > to engage the connector. If the bayonette turns too easily it > doesn't > maintain sufficient engagement force to keep the RF connections > in proper alignment. > > > 73 > Frank > W3LPL > > > > > - Original Message - > > From: "Wes Stewart" > To: elecraft@mailman.qth.net > Sent: Tuesday, September 18, 2018 5:51:45 PM > Subject: Re: [Elecraft] loss of RX sensitivity > > It's difficult to argue with Frank's experience and expertise. That > said, fools > rush in... > > I own some network analyzers, 1) an N2PK which I built with type N > connectors, > 2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert > AA-55 Zoom > with a SO239. Professionally, I've used analyzers with type N, 3.5mm > (beadless > SMA) and K connectors. With the exception of the AA-55, which only > goes to 55 > MHz, all of these can be calibrated with "precision" calibration > kits that can > cost thousands of dollars. So far, Frank is right, not a BNC in the > bunch. > > But that has changed with the introduction of the DG5MK's FA-VA5, > one-port > vector analyzer. I am on the reserve list to buy one of these. The > thing to > note is that it is supplied with a BNC connector. There has been a > lot of > anguish, heartburn, etc about this on the VNWA Yahoo group but the > consensus is > that it will be fine and BNC calibration kit has been developed and > tested > without issue. https://www.youtube.com/watch?v=X8Z7veGV57o > > There are tens of thousands of BNCs on oscilloscopes and other > instruments and > I've seldom had an issue with them in 30+ years of lab work. For > quick > disconnect I also use short jumper cables with BNCs to break the > connections > between the hardline running to the tower and the cable entrance to > the shack > during lightning season. Admittedly, I'm only running 500 W. When I > can leave > them more permanently connected I revert to type N. > > Wes N7WS > > On 9/17/2018 5:04 PM, donov...@starpower.net wrote: > > If you have a vector network analyzer you'll discover that BNC > > connectors aren't all that great at VHF and above, l oss and > > impedance vary with connector axial alignment because the bayonnet > > > shell doesn't support aligh the connector body very well. Strain > relief > > is extremely important with BNC connectors. TNC connectors are > > far superior but not widely used. > > > > > > While professionally installed N connectors have superb RF > > characteristics, all too often they're improperly installed -- > even by > > professionals -- leading to damaged connectors if the male pin is > > > misaligned, or unreliable contact if the pin or socket depth is > just a > > few millimeters less than the manufacturers specification. I use > > only captive pin male N connectors, avoiding the most severe > > problems. I never use female N connectors on cables, the N sockets > > > are much too fragile. > > > > > > Its hard to beat high quality silver plated UHF connectors at HF > and > > 6 meters. But its important to use a tool to tighten them. That's > a > > small price to pay for a very reliable connector. > > > > > > 73 > > Frank > > W3LPL > > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to donov...@starpower.net > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to riese-k3...@juno.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
On 9/18/2018 1:53 PM, donov...@starpower.net wrote: What is its current selling price? Frank, I believe it's under $200. https://www.sdr-kits.net/VA5_Page 73, Jim __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Hi Wes, Thanks for forwarding the information about DG5MK's new FA-VA5 VNA. What is its current selling price? If you use many BNC connectors, you'll notice a distinct difference in connector quality especially above 100 MHz. Avoid using BNC male connectors with weak tension when you turn the bayonette to engage the connector. If the bayonette turns too easily it doesn't maintain sufficient engagement force to keep the RF connections in proper alignment. 73 Frank W3LPL - Original Message - From: "Wes Stewart" To: elecraft@mailman.qth.net Sent: Tuesday, September 18, 2018 5:51:45 PM Subject: Re: [Elecraft] loss of RX sensitivity It's difficult to argue with Frank's experience and expertise. That said, fools rush in... I own some network analyzers, 1) an N2PK which I built with type N connectors, 2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert AA-55 Zoom with a SO239. Professionally, I've used analyzers with type N, 3.5mm (beadless SMA) and K connectors. With the exception of the AA-55, which only goes to 55 MHz, all of these can be calibrated with "precision" calibration kits that can cost thousands of dollars. So far, Frank is right, not a BNC in the bunch. But that has changed with the introduction of the DG5MK's FA-VA5, one-port vector analyzer. I am on the reserve list to buy one of these. The thing to note is that it is supplied with a BNC connector. There has been a lot of anguish, heartburn, etc about this on the VNWA Yahoo group but the consensus is that it will be fine and BNC calibration kit has been developed and tested without issue. https://www.youtube.com/watch?v=X8Z7veGV57o There are tens of thousands of BNCs on oscilloscopes and other instruments and I've seldom had an issue with them in 30+ years of lab work. For quick disconnect I also use short jumper cables with BNCs to break the connections between the hardline running to the tower and the cable entrance to the shack during lightning season. Admittedly, I'm only running 500 W. When I can leave them more permanently connected I revert to type N. Wes N7WS On 9/17/2018 5:04 PM, donov...@starpower.net wrote: > If you have a vector network analyzer you'll discover that BNC > connectors aren't all that great at VHF and above, l oss and > impedance vary with connector axial alignment because the bayonnet > shell doesn't support aligh the connector body very well. Strain relief > is extremely important with BNC connectors. TNC connectors are > far superior but not widely used. > > > While professionally installed N connectors have superb RF > characteristics, all too often they're improperly installed -- even by > professionals -- leading to damaged connectors if the male pin is > misaligned, or unreliable contact if the pin or socket depth is just a > few millimeters less than the manufacturers specification. I use > only captive pin male N connectors, avoiding the most severe > problems. I never use female N connectors on cables, the N sockets > are much too fragile. > > > Its hard to beat high quality silver plated UHF connectors at HF and > 6 meters. But its important to use a tool to tighten them. That's a > small price to pay for a very reliable connector. > > > 73 > Frank > W3LPL > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
It's difficult to argue with Frank's experience and expertise. That said, fools rush in... I own some network analyzers, 1) an N2PK which I built with type N connectors, 2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert AA-55 Zoom with a SO239. Professionally, I've used analyzers with type N, 3.5mm (beadless SMA) and K connectors. With the exception of the AA-55, which only goes to 55 MHz, all of these can be calibrated with "precision" calibration kits that can cost thousands of dollars. So far, Frank is right, not a BNC in the bunch. But that has changed with the introduction of the DG5MK's FA-VA5, one-port vector analyzer. I am on the reserve list to buy one of these. The thing to note is that it is supplied with a BNC connector. There has been a lot of anguish, heartburn, etc about this on the VNWA Yahoo group but the consensus is that it will be fine and BNC calibration kit has been developed and tested without issue. https://www.youtube.com/watch?v=X8Z7veGV57o There are tens of thousands of BNCs on oscilloscopes and other instruments and I've seldom had an issue with them in 30+ years of lab work. For quick disconnect I also use short jumper cables with BNCs to break the connections between the hardline running to the tower and the cable entrance to the shack during lightning season. Admittedly, I'm only running 500 W. When I can leave them more permanently connected I revert to type N. Wes N7WS On 9/17/2018 5:04 PM, donov...@starpower.net wrote: If you have a vector network analyzer you'll discover that BNC connectors aren't all that great at VHF and above, l oss and impedance vary with connector axial alignment because the bayonnet shell doesn't support aligh the connector body very well. Strain relief is extremely important with BNC connectors. TNC connectors are far superior but not widely used. While professionally installed N connectors have superb RF characteristics, all too often they're improperly installed -- even by professionals -- leading to damaged connectors if the male pin is misaligned, or unreliable contact if the pin or socket depth is just a few millimeters less than the manufacturers specification. I use only captive pin male N connectors, avoiding the most severe problems. I never use female N connectors on cables, the N sockets are much too fragile. Its hard to beat high quality silver plated UHF connectors at HF and 6 meters. But its important to use a tool to tighten them. That's a small price to pay for a very reliable connector. 73 Frank W3LPL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Captivated pin N connectors completely resolve the problem of the center pin pulling back in cold weather. 73 Frank W3LPL - Original Message - From: "Dr. William J. Schmidt" To: "Elecraft Reflector" Sent: Tuesday, September 18, 2018 3:29:41 PM Subject: Re: [Elecraft] loss of RX sensitivity [[The next time someone challenges me on why I only use BNC and Type N connectors, I’m going to send them this entire discussion.]] Unfortunately this is not perfect either. If you use an "N" connector on long runs of heliax in a cold climate, you must be aware that the coefficients of expansion of the center conductor and the shield can be different... and on several occasions, I have seen the center pin pull back from the connector (and essentially disconnect) because the center conductor contracted more than the shield. Nb. This does not happen with all "N" connectors. This is less of a problem with BNC connectors because the coax used is generally has a somewhat flexible shield. --- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
[[The next time someone challenges me on why I only use BNC and Type N connectors, I’m going to send them this entire discussion.]] Unfortunately this is not perfect either. If you use an "N" connector on long runs of heliax in a cold climate, you must be aware that the coefficients of expansion of the center conductor and the shield can be different... and on several occasions, I have seen the center pin pull back from the connector (and essentially disconnect) because the center conductor contracted more than the shield. Nb. This does not happen with all "N" connectors. This is less of a problem with BNC connectors because the coax used is generally has a somewhat flexible shield. --- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Trouble is I have to put adapters on the equipment and then go to bnc Chuck Jack KE9UW Sent from my iPhone, cjack > On Sep 17, 2018, at 6:46 PM, Walter Underwood wrote: > > The next time someone challenges me on why I only use BNC and Type N > connectors, I’m going to send them this entire discussion. > > wunder > K6WRU > Walter Underwood > CM87wj > http://observer.wunderwood.org/ (my blog) > >> On Sep 17, 2018, at 4:41 PM, Don Wilhelm wrote: >> >> Andy, >> >> The PL259 to SO239 connector "end face" contact is provided only by pressure >> - it is not a sliding contact as you would find in a BNC or an N connector. >> The pressure is provided only by the tightening of the threaded portion of >> the PL259. >> >> I ask you - just how much resistance can be expected if you just touch two >> ends of wires together without further positive contact? >> >> The "insulating spacer" is any oxidation on either the SO239 or the PL259. >> That is why I like silver plated UHF connectors. They may look a bit >> corroded, but the silver oxide is conductive even though it can appear brown >> or black. If you are shopping for UHF connectors at hamfests, avoid all >> those nickel-plated ones that a not Amphenol, but flock to those that are >> oxidized, and silver plated with Mil Spec designations on them. >> >> 73, >> Don W3FPR >> >>> On 9/17/2018 6:39 PM, ANDY DURBIN wrote: >>> " the threads of the PL259 are providing the only contact with the SO239" >>> In the connectors that you are mating how do you prevent contact between >>> the end face of the PL259 body and the end face of the SO239 body? You >>> would need an insulating spacer for your statement to be true. >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to wun...@wunderwood.org > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to c-haw...@illinois.edu __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
If you have a vector network analyzer you'll discover that BNC connectors aren't all that great at VHF and above, l oss and impedance vary with connector axial alignment because the bayonnet shell doesn't support aligh the connector body very well. Strain relief is extremely important with BNC connectors. TNC connectors are far superior but not widely used. While professionally installed N connectors have superb RF characteristics, all too often they're improperly installed -- even by professionals -- leading to damaged connectors if the male pin is misaligned, or unreliable contact if the pin or socket depth is just a few millimeters less than the manufacturers specification. I use only captive pin male N connectors, avoiding the most severe problems. I never use female N connectors on cables, the N sockets are much too fragile. Its hard to beat high quality silver plated UHF connectors at HF and 6 meters. But its important to use a tool to tighten them. That's a small price to pay for a very reliable connector. 73 Frank W3LPL - Original Message - From: "Walter Underwood" To: elecraft@mailman.qth.net Sent: Monday, September 17, 2018 11:45:10 PM Subject: Re: [Elecraft] loss of RX sensitivity The next time someone challenges me on why I only use BNC and Type N connectors, I’m going to send them this entire discussion. wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Sep 17, 2018, at 4:41 PM, Don Wilhelm wrote: > > Andy, > > The PL259 to SO239 connector "end face" contact is provided only by pressure > - it is not a sliding contact as you would find in a BNC or an N connector. > The pressure is provided only by the tightening of the threaded portion of > the PL259. > > I ask you - just how much resistance can be expected if you just touch two > ends of wires together without further positive contact? > > The "insulating spacer" is any oxidation on either the SO239 or the PL259. > That is why I like silver plated UHF connectors. They may look a bit > corroded, but the silver oxide is conductive even though it can appear brown > or black. If you are shopping for UHF connectors at hamfests, avoid all those > nickel-plated ones that a not Amphenol, but flock to those that are oxidized, > and silver plated with Mil Spec designations on them. > > 73, > Don W3FPR > > On 9/17/2018 6:39 PM, ANDY DURBIN wrote: >> " the threads of the PL259 are providing the only contact with the SO239" >> In the connectors that you are mating how do you prevent contact between the >> end face of the PL259 body and the end face of the SO239 body? You would >> need an insulating spacer for your statement to be true. > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to wun...@wunderwood.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Pretty much my point made in another post. In fact, I often take a perverse view of these situations and ask myself, "Self, if you wanted to screw these two things together without the faces touching, how difficult would it be to do?" And of course the answer is, almost impossible. Wes N7ws On 9/17/2018 3:39 PM, ANDY DURBIN wrote: " the threads of the PL259 are providing the only contact with the SO239" In the connectors that you are mating how do you prevent contact between the end face of the PL259 body and the end face of the SO239 body? You would need an insulating spacer for your statement to be true. 73, Andy k3wyc __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
This is one of those, "it depends" situations. Depending on the location of the two center conductor insulators in the plug and socket, the serrated (toothed) surface of the female connector might well contact the mating plug surface, if there is a gap between the insulators. In fact the "tighten it with pliers" crowd might actually be forcing this connection and mistakenly believing that they are improving the connection via the threads. Wes N7WS On 9/17/2018 3:22 PM, Don Wilhelm wrote: Chuck, That is true, but is ignoring the fact that the threads of the PL259 are providing the only contact with the SO239. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
The next time someone challenges me on why I only use BNC and Type N connectors, I’m going to send them this entire discussion. wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Sep 17, 2018, at 4:41 PM, Don Wilhelm wrote: > > Andy, > > The PL259 to SO239 connector "end face" contact is provided only by pressure > - it is not a sliding contact as you would find in a BNC or an N connector. > The pressure is provided only by the tightening of the threaded portion of > the PL259. > > I ask you - just how much resistance can be expected if you just touch two > ends of wires together without further positive contact? > > The "insulating spacer" is any oxidation on either the SO239 or the PL259. > That is why I like silver plated UHF connectors. They may look a bit > corroded, but the silver oxide is conductive even though it can appear brown > or black. If you are shopping for UHF connectors at hamfests, avoid all > those nickel-plated ones that a not Amphenol, but flock to those that are > oxidized, and silver plated with Mil Spec designations on them. > > 73, > Don W3FPR > > On 9/17/2018 6:39 PM, ANDY DURBIN wrote: >> " the threads of the PL259 are providing the only contact with the SO239" >> In the connectors that you are mating how do you prevent contact between the >> end face of the PL259 body and the end face of the SO239 body? You would >> need an insulating spacer for your statement to be true. > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to wun...@wunderwood.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Andy, The PL259 to SO239 connector "end face" contact is provided only by pressure - it is not a sliding contact as you would find in a BNC or an N connector. The pressure is provided only by the tightening of the threaded portion of the PL259. I ask you - just how much resistance can be expected if you just touch two ends of wires together without further positive contact? The "insulating spacer" is any oxidation on either the SO239 or the PL259. That is why I like silver plated UHF connectors. They may look a bit corroded, but the silver oxide is conductive even though it can appear brown or black. If you are shopping for UHF connectors at hamfests, avoid all those nickel-plated ones that a not Amphenol, but flock to those that are oxidized, and silver plated with Mil Spec designations on them. 73, Don W3FPR On 9/17/2018 6:39 PM, ANDY DURBIN wrote: " the threads of the PL259 are providing the only contact with the SO239" In the connectors that you are mating how do you prevent contact between the end face of the PL259 body and the end face of the SO239 body? You would need an insulating spacer for your statement to be true. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] loss of RX sensitivity
" the threads of the PL259 are providing the only contact with the SO239" In the connectors that you are mating how do you prevent contact between the end face of the PL259 body and the end face of the SO239 body? You would need an insulating spacer for your statement to be true. 73, Andy k3wyc __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Chuck, That is true, but is ignoring the fact that the threads of the PL259 are providing the only contact with the SO239. They must be solidly tight for reliable conductivity to the shield of the coax. All contact from the SO239 to the coax shield is by pressure contact. Finger tight may "work", but unless one has very strong fingers, that is not tight enough to assure a good connection. A parallel is putting a locking nut on a screw by using a 2nd nut - often done if you want to use the screw as an axle, like putting the screw through a hinge (think a trailer rear gate). If you put the 2nd nut on the screw with only finger pressure, it will likely back off with slight vibration and twisting nullifying the locking effect. OTOH, if you fasten the two nuts together with a slight twist of the wrenches, the two nuts will not move and will remain locked together. It is not the friction between the 2 nuts that does it, but there is a slight elongation of the screw threads that keeps significant pressure on the two nuts to keep them together. The same principle applies to a PL-259 to SO-239 thread engagement. We may have "gotten away" with only finger tight in the past, but is one possible cause of failure. 73, Don W3FPR On 9/17/2018 5:05 PM, hawley, charles j jr wrote: I've found that wiggling the body of the plug while tightening the threads makes the pl259 quite tight with the pins firmly seated in the notches. The motion allows the pins to find the deepest well of the notch. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
I've found that wiggling the body of the plug while tightening the threads makes the pl259 quite tight with the pins firmly seated in the notches. The motion allows the pins to find the deepest well of the notch. Chuck Hawley c-haw...@illinois.edu Amateur Radio, KE9UW aka Jack, BMW Motorcycles From: elecraft-boun...@mailman.qth.net [elecraft-boun...@mailman.qth.net] on behalf of Jim Brown [j...@audiosystemsgroup.com] Sent: Monday, September 17, 2018 2:44 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] loss of RX sensitivity On 9/17/2018 9:20 AM, Drew AF2Z wrote: > Note that there is no electrical connection through the threads on the > plug body and the threads on the shell; these threads are merely a > stop to keep the shell from sliding down the cable when not connected > to the SO-239 on the equipment. This is simply not true. The entire PL259 body and shell and the entire mating body are part of the connection. What IS correct is that 1) the connectors must be properly installed both to the coax and the equipment, and 2) that the shell must be well tightened, often described as "wrench tight," with the pins on the PL259 firmly seated in the notches in the mating connector. I'm being generic about mating connectors because it's equally true of SO239 and other connectors like barrels, elbows, tees, and inter-series adapters. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to c-haw...@illinois.edu __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Yes, regardless of how good they look, always snug the PL-259 with a small pair of Channel Lock pliers. Finger tight is not good enough. Many of our connectors today are of inferior quality. Also due to the use of jumpers, the flexing and pulling is prone to damage the connection between the coax and connector. Always suspect the jumper and icon doubt, replace it. AND if you find one defective or in question, immediately cut it in two pieces. Thus it won't be used or confused again. Bob, K4TAX Sent from my iPhone > On Sep 17, 2018, at 2:44 PM, Jim Brown wrote: > >> On 9/17/2018 9:20 AM, Drew AF2Z wrote: >> Note that there is no electrical connection through the threads on the plug >> body and the threads on the shell; these threads are merely a stop to keep >> the shell from sliding down the cable when not connected to the SO-239 on >> the equipment. > > This is simply not true. The entire PL259 body and shell and the entire > mating body are part of the connection. What IS correct is that 1) the > connectors must be properly installed both to the coax and the equipment, and > 2) that the shell must be well tightened, often described as "wrench tight," > with the pins on the PL259 firmly seated in the notches in the mating > connector. I'm being generic about mating connectors because it's equally > true of SO239 and other connectors like barrels, elbows, tees, and > inter-series adapters. > > 73, Jim K9YC > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to rmcg...@blomand.net > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
On 9/17/2018 9:20 AM, Drew AF2Z wrote: Note that there is no electrical connection through the threads on the plug body and the threads on the shell; these threads are merely a stop to keep the shell from sliding down the cable when not connected to the SO-239 on the equipment. This is simply not true. The entire PL259 body and shell and the entire mating body are part of the connection. What IS correct is that 1) the connectors must be properly installed both to the coax and the equipment, and 2) that the shell must be well tightened, often described as "wrench tight," with the pins on the PL259 firmly seated in the notches in the mating connector. I'm being generic about mating connectors because it's equally true of SO239 and other connectors like barrels, elbows, tees, and inter-series adapters. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Real easy to see on a spectrum analyzer with a tracking generator. The trace goes wild as soon as you start turning the PL-259 connector by hand (please don't use pliers on your SA). 73, Ian N8IK On Mon, Sep 17, 2018 at 12:59 PM, Don Wilhelm wrote: > Drew and all, > > I beg to differ, unless you meant something different than I read. > The threads on a PL-259 connector are the only thing that connects the > coax shield to the SO-239 jack. > > That is why hand tightening of PL-259 connectors is not sufficient. Use > pliers to snug them up just a bit more to assure a good connection. > > BNC and N connectors do not have a similar requirement. They will make > positive contact without being tightened. > > 73, > Don W3FPR > > On 9/17/2018 12:20 PM, Drew AF2Z wrote: > > >> Note that there is no electrical connection through the threads on the >> plug body and the threads on the shell; these threads are merely a stop to >> keep the shell from sliding down the cable when not connected to the SO-239 >> on the equipment. >> >> __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to iann...@gmail.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Drew and all, I beg to differ, unless you meant something different than I read. The threads on a PL-259 connector are the only thing that connects the coax shield to the SO-239 jack. That is why hand tightening of PL-259 connectors is not sufficient. Use pliers to snug them up just a bit more to assure a good connection. BNC and N connectors do not have a similar requirement. They will make positive contact without being tightened. 73, Don W3FPR On 9/17/2018 12:20 PM, Drew AF2Z wrote: Note that there is no electrical connection through the threads on the plug body and the threads on the shell; these threads are merely a stop to keep the shell from sliding down the cable when not connected to the SO-239 on the equipment. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
I used that trick to keep my DSL line running for a couple of years when Verizon was abandoning copper and no longer interested in doing maintenance. Placing a resistor across the telephone line would draw a constant small current, not enough to off-hook the line but enough to "seal" the poor connection, wherever it was, and improve the noise margin. Regarding the PL-259 center pin-- it's also important to check the connection between the threaded shell and the body of the plug. That is a common and overlooked connection point subject to poor connection. Note that there is no electrical connection through the threads on the plug body and the threads on the shell; these threads are merely a stop to keep the shell from sliding down the cable when not connected to the SO-239 on the equipment. The electrical connection occurs through the lip at the back of the shell which butts against the threaded region on the plug. The area of this thin ring of contact is pretty small so it's important that the mating surfaces are entirely clean and free of corrosion. It may help to disconnect the cable, then hold the back of the plug in one hand (where the cable enters it), then pull on the shell with the other hand, toward the pin end, as if trying to pull it off the plug; while maintaining this pressure, twist the shell vigorously. That will help clean the mating surfaces, especially if the plug is not silver plated but that cheap "shiny metal" stuff a lot of plugs have now. Also do this with all jumpers between SWR meter, matchbox, etc. 73, Drew AF2Z On 09/17/18 01:44, Frederick Dwight wrote: Scott, The problem you describe is actually quite common in electronics. In the telephone industry, especially in the “good old days” with wire cables, sometimes with many splices it was common to get drop outs. These could be due to a splice, wire wrap connection, oxidized relay contact or whatever, especially with only low level signals. If the circuit also had a DC voltage on it, the problem often did not exist. In fact it was common on critical circuits for the FAA or military, or whatever to sometimes just put “sealing current” on certain circuits just to be sure it was reliable. Often we used 24 volts DC or less with only a few ma of current. At one time I had many phased verticals which were controlled by many relays. Occasionally the received signal would drop by many S units. Sending a single dot, even with QRP or QRPP power always cleared the problem, sometimes for weeks or months. So it could be a connection in the antenna system, a plug on a circuit board, or even a relay. I have never experienced trouble with Elecraft relays personally. Sometimes PL-259 center pins are not correctly soldered, and can present similar symptoms. You could try a random wire, or even something like an 80 meter dipole on 30 meters, just to see if it was anywhere in the antenna system. Even a volt or two is often enough to punch through a poor solder or oxidized connection, but even something like a 0 dBm signal is just not enough. I have identified problems with BNC connectors and adaptors purchased at ham flea markets which are just not reliable and are probably factory rejects. So look into your antenna system before you dig into your rig. You could also hook a signal generator to the rig and see if it receives OK on all bands with something like less than an S9 signal. Be sure to not transmit into your generator, and/or set your tx to very low power. Good Luck Rick KL7CW Sent from Mail for Windows 10 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to pu...@af2z.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
Reminds me of having to blow on the contacts in a Nintendo game cartridge to make it work in the console. ;) On Mon, Sep 17, 2018 at 7:31 AM rich hurd WC3T wrote: > I guess that’s the electronic equivalent of blowing through a tube to clear > the blockage. :) > > On Mon, Sep 17, 2018 at 01:44 Frederick Dwight > wrote: > > > Scott, > > The problem you describe is actually quite common in electronics. > In > > the telephone industry, especially in the “good old days” with wire > cables, > > sometimes with many splices it was common to get drop outs. These could > be > > due to a splice, wire wrap connection, oxidized relay contact or > whatever, > > especially with only low level signals. If the circuit also had a DC > > voltage on it, the problem often did not exist. In fact it was common on > > critical circuits for the FAA or military, or whatever to sometimes just > > put “sealing current” on certain circuits just to be sure it was > reliable. > > Often we used 24 volts DC or less with only a few ma of current. At one > > time I had many phased verticals which were controlled by many relays. > > Occasionally the received signal would drop by many S units. Sending a > > single dot, even with QRP or QRPP power always cleared the problem, > > sometimes for weeks or months. So it could be a connection in the > antenna > > system, a plug on a circuit board, or even a relay. I have never > > experienced trouble with Elecraft relays personally. Sometimes PL-259 > > center pins are not correctly soldered, and can present similar symptoms. > > You could try a random wire, or even something like an 80 meter dipole on > > 30 meters, just to see if it was anywhere in the antenna system. Even a > > volt or two is often enough to punch through a poor solder or oxidized > > connection, but even something like a 0 dBm signal is just not enough. I > > have identified problems with BNC connectors and adaptors purchased at > ham > > flea markets which are just not reliable and are probably factory > rejects. > > So look into your antenna system before you dig into your rig. You could > > also hook a signal generator to the rig and see if it receives OK on all > > bands with something like less than an S9 signal. Be sure to not > transmit > > into your generator, and/or set your tx to very low power. Good Luck > > Rick KL7CW > > > > Sent from Mail for Windows 10 > > > > __ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Elecraft@mailman.qth.net > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to r...@wc3t.us > > -- > 72, > Rich Hurd / WC3T / DMR: 3142737 > Northampton County RACES, EPA-ARRL Public Information Officer for Scouting > Latitude: 40.761621 Longitude: -75.288988 (40°45.68' N 75°17.33' W) Grid: > *FN20is* > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to ard...@gmail.com -- -+-+-+-+- Jenny Everywhere's Infinite: Quark Time http://quarktime.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] loss of RX sensitivity
I guess that’s the electronic equivalent of blowing through a tube to clear the blockage. :) On Mon, Sep 17, 2018 at 01:44 Frederick Dwight wrote: > Scott, > The problem you describe is actually quite common in electronics. In > the telephone industry, especially in the “good old days” with wire cables, > sometimes with many splices it was common to get drop outs. These could be > due to a splice, wire wrap connection, oxidized relay contact or whatever, > especially with only low level signals. If the circuit also had a DC > voltage on it, the problem often did not exist. In fact it was common on > critical circuits for the FAA or military, or whatever to sometimes just > put “sealing current” on certain circuits just to be sure it was reliable. > Often we used 24 volts DC or less with only a few ma of current. At one > time I had many phased verticals which were controlled by many relays. > Occasionally the received signal would drop by many S units. Sending a > single dot, even with QRP or QRPP power always cleared the problem, > sometimes for weeks or months. So it could be a connection in the antenna > system, a plug on a circuit board, or even a relay. I have never > experienced trouble with Elecraft relays personally. Sometimes PL-259 > center pins are not correctly soldered, and can present similar symptoms. > You could try a random wire, or even something like an 80 meter dipole on > 30 meters, just to see if it was anywhere in the antenna system. Even a > volt or two is often enough to punch through a poor solder or oxidized > connection, but even something like a 0 dBm signal is just not enough. I > have identified problems with BNC connectors and adaptors purchased at ham > flea markets which are just not reliable and are probably factory rejects. > So look into your antenna system before you dig into your rig. You could > also hook a signal generator to the rig and see if it receives OK on all > bands with something like less than an S9 signal. Be sure to not transmit > into your generator, and/or set your tx to very low power. Good Luck > Rick KL7CW > > Sent from Mail for Windows 10 > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to r...@wc3t.us -- 72, Rich Hurd / WC3T / DMR: 3142737 Northampton County RACES, EPA-ARRL Public Information Officer for Scouting Latitude: 40.761621 Longitude: -75.288988 (40°45.68' N 75°17.33' W) Grid: *FN20is* __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] loss of RX sensitivity
Scott, The problem you describe is actually quite common in electronics. In the telephone industry, especially in the “good old days” with wire cables, sometimes with many splices it was common to get drop outs. These could be due to a splice, wire wrap connection, oxidized relay contact or whatever, especially with only low level signals. If the circuit also had a DC voltage on it, the problem often did not exist. In fact it was common on critical circuits for the FAA or military, or whatever to sometimes just put “sealing current” on certain circuits just to be sure it was reliable. Often we used 24 volts DC or less with only a few ma of current. At one time I had many phased verticals which were controlled by many relays. Occasionally the received signal would drop by many S units. Sending a single dot, even with QRP or QRPP power always cleared the problem, sometimes for weeks or months. So it could be a connection in the antenna system, a plug on a circuit board, or even a relay. I have never experienced trouble with Elecraft relays personally. Sometimes PL-259 center pins are not correctly soldered, and can present similar symptoms. You could try a random wire, or even something like an 80 meter dipole on 30 meters, just to see if it was anywhere in the antenna system. Even a volt or two is often enough to punch through a poor solder or oxidized connection, but even something like a 0 dBm signal is just not enough. I have identified problems with BNC connectors and adaptors purchased at ham flea markets which are just not reliable and are probably factory rejects. So look into your antenna system before you dig into your rig. You could also hook a signal generator to the rig and see if it receives OK on all bands with something like less than an S9 signal. Be sure to not transmit into your generator, and/or set your tx to very low power. Good Luck Rick KL7CW Sent from Mail for Windows 10 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
