[Elecraft] Elecraft CW Net 19th Anniversary Announcement
Good Evening, This week was sunny and hot. Plants and insects grew very well. I was able to build three antennas but only raised one of them. I am coax challenged. A few more runs plus an antenna switch will be on order soon. Four antennas should give me paths into much of North America. If the bands ever strengthen the world may open up again. I have checked in folks from European and Asian Russia, Hungary, Iceland, Ireland, a few South American countries, and a few island nations in the Pacific. There were a few African contacts with at least one from the Middle East. None, so far, from South or Southeastern Asia. I did forget to mention both Australia and New Zealand. I missed Antarctica but logged him via relay. I started the Elecraft CW Net on June 6th, 2002. Many people have checked in over the years. The format of the directed net was designed by N0SS, Tom Hammond (SK). He helped for many years as an alternate net control from Missouri. I miss him. Wayne, N6KR, once asked me how I had kept running the net for so long. I told him it had become a habit. A good habit. One where I get to meet new people and learn a bit more about the regulars. I think I have been skunked only once and for only one of the two nets. Sometimes the bands are just too poor. Other times folks are busy with holidays. But I still get a few folks each week. Procedures have changed a little since the beginning. I am finally learning how to run a net. The only strict rule is to have fun. Well, the directed net part is kind of strict too, but without some control there is chaos. Much like the transition from laminar to turbulent flow. A little disorder is OK as long as everyone knows who is talking to whom. "Little whorls have lesser whirls and so on to viscosity." Tomorrow will be the 19th anniversary celebration of the Elecraft CW Net. Lime jello, cookies, and cherry pie for the lucky few. Oh and fresh sour dough bread. Now for an entree :) The rhododendron are in full bloom as are the nicely scented False Solomon Seal. Many species of butterflies are enjoying a feast. Both species of hummingbirds are on display (Rufous & Anna's). So warm up your heaters and get your tubes glowing (I can dream) and see if the bands will support comms to NW Oregon (where it is back to 50 degrees with rain). Please join us on (or near): 14050 kHz at 2200z Sunday (3 PM PDT Sunday) Maybe way off if I can find room. 7047 kHz at z Monday (5 PM PDT Sunday) 73, Kevin. KD5ONS - https://www.quantamagazine.org/mathematicians-identify-threshold-at-which-shapes-give-way-20210603/ __ 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] K-3 does not turn on.
Hi Antonio, Am 05.06.21 um 16:23 schrieb Antonio Madeira: > Greetings, this is my first approach to the qth.net. > > My K-3, assembled from the factory, quite a few years ago, shows the very > first failure, > it does not turn on. Voltage at the power socket is 13.5VDC. > > Where shall I look? Check, that you did not swap + and - of the power cable! Unfortunately this happened once to me and this way I "desoldered" D11 and almost desoldered D12 off of the KPA3 (luckily both diodes survived this treatment and the K3 worked after putting them back in place again) What happens if you remove the KPA3, does the K3 power on then? > Vy 73 > Antonio - CU8AS Sorry that's all I could contribute here Vy 73 es 55 Thorsten, DH4FT __ 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] KPA500 receive loss
Even (sub) nano second (ns) fast acting gas tubes are primarily not a safe solution to RX front end burnout protection. Semiconductors: Issues: Energy Protection level, RX Intermodulation prevention. There are however some fast semiconductor diodes (ESD protection) available with low capacitance. They have safe enough voltage protection level even for sensitive RX electronics, but limited energy absorption. Spark gaps: A several kV, ns-fast, transient (ESD, EMP, high dV/dt) voltage RX input spike may be better limited in energy but more voltage amplitude; still around 800 to 1000V left over for a short time. Suitable spark gap can trigger quickly (dV/dt dependent). There is always some time delay in gap breakdown. Sensitive RX components need to survive that safely, without being pre-damaged . This low pressure gas ionization process is also governed by HV breakdown Paschen law https://en.wikipedia.org/wiki/Paschen%27s_law . The number of first available free gas electrons, needed for a quick avalanche breakdown, are important. By gap fast overvolting (field emission process from electrodes-> source of free electrons, without radioactive , ionizing material ) the spark gap is triggered. The gas tube would fire at much lower DC voltage levels ( e.g. <100.. 200V+ ) Fast pulse triggering creates a very broadband spectrum of the residual onset pulse (Time -Frequency Domain Fourier transformation ) . This triggering is different from a finally, time retarded, development of low resistance breakdown plasma channel. Here the residual voltage may be 30 to 50V. Too bad, the first spike may have already killed the RX. Therefore , if capacitance is not an issue (no HF RX) , one uses low pass filters after the spark gap. To control the energy reduction one can use additionally multi-stage protection modules ( 1.) Gap tube-full energy ,2.) elevated energy semiconductor, 3.) low energy semiconductor ) The triggering of the stages must be well time coordinated. If AC voltages are continuously present in PS Networks , the spark gap (low R Plasma) network follow on currents must be limited to lead to well controlled extinguishing of the gap. PS: One other trick to avoid high capacitances (high VSWR) is to arrange protection diodes in a bridge configuration -cancelling out C One other trick to avoid intermodulation is to DC bias diodes appropriately. Experience furthermore teaches: Even 4 unbiased Schottky Diodes ( ca. 0.3V each ) in series/anti parallel at RX front end are often critical regarding INTERMOD , e.g.in multi TX contest site scenarios ) End of lecture ...if considered too long and irrelevant just ignore it Hi Hi -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Dr. William J. Schmidt Sent: Samstag, 5. Juni 2021 18:02 To: 'Elecraft Mail List' Subject: Re: [Elecraft] KPA500 receive loss I'm sure you could invent many ways to protect these parts (gas tubes, sacrificial TVS diodes, fusing, etc.). The best way, of course, is to disconnect it (which of course I did not do). These are low voltage parts on the receive side path so I don't know if a gas tube would be appropriate here... Someone with more experience with them can chime in here. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ email: b...@wjschmidt.com -Original Message- From: CUTTER DAVID Sent: Saturday, June 5, 2021 10:46 AM To: b...@wjschmidt.com; Elecraft Mail List Subject: Re: [Elecraft] KPA500 receive loss Would a gas discharge tube save the sensitive parts? David G3UNA > On 05 June 2021 at 16:20 "Dr. William J. Schmidt" wrote: > > > This happened with my backup amp at the contest station on J6. I left > it connected by accident overnight (too much rum) and we had some > static storms. Took out the pin diodes (well, more accurately the > diodes that act like PIN diodes). When put in operate, the receive > drops by 30+ dB but still transmits fine. A simple replacement of the > four diodes and three (?) transistors solved the problem. Dirt cheap. > You can make these measurements at the test-points to confirm: > > > TP2= RX 13.1, TX 0.8 > TP4= RX 3.9, TX 13 > > > Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ > PJ2/K9HZ > > email: b...@wjschmidt.com > -- 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 hb9...@hispeed.ch __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post:
Re: [Elecraft] KPA500 receive loss
This doesn’t really have the signature of pin-diode failure. When the pin diodes fail you generally get major signal loss across all bands. The description simply does not match that diagnosis. I would ask for further information: * Is there any change in 160m transmit operation (change in drive requirement)? * Was any retuning of the 160m antenna required? * How is the 160m antenna connected? Might it be split to another load somehow? * Any other changes you see? Let’s try to diagnose the whole situation. This might not be in the KPA at all, or might be something completely different. 73, Jack, W6FB > On Jun 5, 2021, at 12:05 AM, HP via Elecraft wrote: > > Just noticed this evening that on 160 I lose about 6 dB of rx level (noise > and signal ) when I go from STDBY to OPER. On 40 maybe a dB or so , on 20 no > change -- On160 almost always am using RX antenna so am not going thru the > KPA but this evening had Tx ant on RX . > > Maybe has always been that way and just never noticed ??? > > Hank K7HP > > __ > 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 jackbrin...@me.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] KPA500 receive loss
Does that confirm correctness, or brokenness? 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist, RFI ARRL Asst. Director, NW Division, Technical Resources On 6/5/21 8:20 AM, Dr. William J. Schmidt wrote: This happened with my backup amp at the contest station on J6. I left it connected by accident overnight (too much rum) and we had some static storms. Took out the pin diodes (well, more accurately the diodes that act like PIN diodes). When put in operate, the receive drops by 30+ dB but still transmits fine. A simple replacement of the four diodes and three (?) transistors solved the problem. Dirt cheap. You can make these measurements at the test-points to confirm: TP2= RX 13.1, TX 0.8 TP4= RX 3.9, TX 13 Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ email: b...@wjschmidt.com -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Andy Durbin Sent: Saturday, June 5, 2021 8:20 AM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA500 receive loss There was a similar report fairly recently. I copied this to my KPA500 notes: "Reported problem(s): Receive signal is attenuated when in operate. Receive signal is normal when in standby. Problem(s) found: Confirmed problem. Found that D8, D9 and R7 in the T/R circuit had failed. Repair(s) performed: Replaced D8, D9, and R7 on the LPF board." I didn't record who posted this but I expect you will find this and similar reports in the archive. Here is another that may be related: "Elecraft list May 1 2021: I'm repairing a KPA500 for a friend that has the RX loss in standby mode. After a time, he also lost receive in operate mode. After doing a teardown, I found the problem. With the PA board removed, I checked K23A relay. The normally closed contact on the antenna side of the relay was open. K23B was OK. With relay on the board, there was no safe way to energize the relay so I didn't check the contacts on the normally open side. I also noticed that resistor R7 was un-populate and pieces of it was stuck to bottom cover. Looking at the PA schematic I came to the conclusion that the relay K23A was also having problems on the operate position. With no or a poor connection to the antenna, the 500-watt output voltage can go sky high. It can get rectified by D9 and feed a high DC voltage through L4 and damage resistor R7 or even un-solder itself. I replaced the relay and R7. I remove the cover on the old relay and using a 12v power supply, I set up bench test. With the relay energized, I connected a Fluke meter in diode mode and it proved that the antenna connection in operate mode was intermittent. - Jack WA9FVP" 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 b...@wjschmidt.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] KPA500 receive loss
I'm sure you could invent many ways to protect these parts (gas tubes, sacrificial TVS diodes, fusing, etc.). The best way, of course, is to disconnect it (which of course I did not do). These are low voltage parts on the receive side path so I don't know if a gas tube would be appropriate here... Someone with more experience with them can chime in here. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ email: b...@wjschmidt.com -Original Message- From: CUTTER DAVID Sent: Saturday, June 5, 2021 10:46 AM To: b...@wjschmidt.com; Elecraft Mail List Subject: Re: [Elecraft] KPA500 receive loss Would a gas discharge tube save the sensitive parts? David G3UNA > On 05 June 2021 at 16:20 "Dr. William J. Schmidt" wrote: > > > This happened with my backup amp at the contest station on J6. I left > it connected by accident overnight (too much rum) and we had some > static storms. Took out the pin diodes (well, more accurately the > diodes that act like PIN diodes). When put in operate, the receive > drops by 30+ dB but still transmits fine. A simple replacement of the > four diodes and three (?) transistors solved the problem. Dirt cheap. > You can make these measurements at the test-points to confirm: > > > TP2= RX 13.1, TX 0.8 > TP4= RX 3.9, TX 13 > > > Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ > PJ2/K9HZ > > email: b...@wjschmidt.com > -- 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] KPA500 receive loss
Would a gas discharge tube save the sensitive parts? David G3UNA > On 05 June 2021 at 16:20 "Dr. William J. Schmidt" wrote: > > > This happened with my backup amp at the contest station on J6. I left it > connected by accident overnight (too much rum) and we had some static > storms. Took out the pin diodes (well, more accurately the diodes that act > like PIN diodes). When put in operate, the receive drops by 30+ dB but > still transmits fine. A simple replacement of the four diodes and three (?) > transistors solved the problem. Dirt cheap. You can make these > measurements at the test-points to confirm: > > > TP2= RX 13.1, TX 0.8 > TP4= RX 3.9, TX 13 > > > Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ > > email: b...@wjschmidt.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] KPA500 receive loss
This happened with my backup amp at the contest station on J6. I left it connected by accident overnight (too much rum) and we had some static storms. Took out the pin diodes (well, more accurately the diodes that act like PIN diodes). When put in operate, the receive drops by 30+ dB but still transmits fine. A simple replacement of the four diodes and three (?) transistors solved the problem. Dirt cheap. You can make these measurements at the test-points to confirm: TP2= RX 13.1, TX 0.8 TP4= RX 3.9, TX 13 Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ email: b...@wjschmidt.com -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Andy Durbin Sent: Saturday, June 5, 2021 8:20 AM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA500 receive loss There was a similar report fairly recently. I copied this to my KPA500 notes: "Reported problem(s): Receive signal is attenuated when in operate. Receive signal is normal when in standby. Problem(s) found: Confirmed problem. Found that D8, D9 and R7 in the T/R circuit had failed. Repair(s) performed: Replaced D8, D9, and R7 on the LPF board." I didn't record who posted this but I expect you will find this and similar reports in the archive. Here is another that may be related: "Elecraft list May 1 2021: I'm repairing a KPA500 for a friend that has the RX loss in standby mode. After a time, he also lost receive in operate mode. After doing a teardown, I found the problem. With the PA board removed, I checked K23A relay. The normally closed contact on the antenna side of the relay was open. K23B was OK. With relay on the board, there was no safe way to energize the relay so I didn't check the contacts on the normally open side. I also noticed that resistor R7 was un-populate and pieces of it was stuck to bottom cover. Looking at the PA schematic I came to the conclusion that the relay K23A was also having problems on the operate position. With no or a poor connection to the antenna, the 500-watt output voltage can go sky high. It can get rectified by D9 and feed a high DC voltage through L4 and damage resistor R7 or even un-solder itself. I replaced the relay and R7. I remove the cover on the old relay and using a 12v power supply, I set up bench test. With the relay energized, I connected a Fluke meter in diode mode and it proved that the antenna connection in operate mode was intermittent. - Jack WA9FVP" 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 b...@wjschmidt.com -- 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
[Elecraft] K-3 does not turn on.
Greetings, this is my first approach to the qth.net. My K-3, assembled from the factory, quite a few years ago, shows the very first failure, it does not turn on. Voltage at the power socket is 13.5VDC. Where shall I look? Vy 73 Antonio - CU8AS __ 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] KPA500 receive loss
There was a similar report fairly recently. I copied this to my KPA500 notes: "Reported problem(s): Receive signal is attenuated when in operate. Receive signal is normal when in standby. Problem(s) found: Confirmed problem. Found that D8, D9 and R7 in the T/R circuit had failed. Repair(s) performed: Replaced D8, D9, and R7 on the LPF board." I didn't record who posted this but I expect you will find this and similar reports in the archive. Here is another that may be related: "Elecraft list May 1 2021: I'm repairing a KPA500 for a friend that has the RX loss in standby mode. After a time, he also lost receive in operate mode. After doing a teardown, I found the problem. With the PA board removed, I checked K23A relay. The normally closed contact on the antenna side of the relay was open. K23B was OK. With relay on the board, there was no safe way to energize the relay so I didn't check the contacts on the normally open side. I also noticed that resistor R7 was un-populate and pieces of it was stuck to bottom cover. Looking at the PA schematic I came to the conclusion that the relay K23A was also having problems on the operate position. With no or a poor connection to the antenna, the 500-watt output voltage can go sky high. It can get rectified by D9 and feed a high DC voltage through L4 and damage resistor R7 or even un-solder itself. I replaced the relay and R7. I remove the cover on the old relay and using a 12v power supply, I set up bench test. With the relay energized, I connected a Fluke meter in diode mode and it proved that the antenna connection in operate mode was intermittent. - Jack WA9FVP" 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
[Elecraft] KPA500 receive loss
Just noticed this evening that on 160 I lose about 6 dB of rx level (noise and signal ) when I go from STDBY to OPER. On 40 maybe a dB or so , on 20 no change -- On160 almost always am using RX antenna so am not going thru the KPA but this evening had Tx ant on RX . Maybe has always been that way and just never noticed ??? Hank K7HP __ 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
