[Elecraft] Elecraft CW Net Report
Good Evening, Twenty meters was more surprising than last week. My first call got no response. But the second one brought Roy, K6XK. I called for more but again no response. I should have known it would be tough. I started the net on 14050 but had someone ask if the frequency was in use. Forty meters was better. The weakest signal was from John, KN5L. On peaks he was hitting S3 but in the troughs of QSB he was gone. Jim mentioned apples. I thought of pie :) On 14050.5 kHz at 2200z: K6XK - Roy - IA On 7047.5 kHz at z: W6JHB - Jim - CA K6PJV - Dale - CA K0DTJ - Brian - CA W0CZ - Ken - ND KN5L - John - TX Now to see the frost early tomorrow morning. I brought a lot of my plants inside but the landscape is going to look very different tomorrow afternoon. In some places the ferns grow to nine feet tall. With a hard frost they fall down. The hunters will be able to see into the forests a little farther. Lots of activity now that it is cooling off. The few deciduous trees we have up here will change color. The deer need to change color too. Until next week stay well, 73, Kevin. KD5ONS - __ 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 - Advantage of min fan speed?
Here are the thresholds level 1: 50 degrees level 2: 55 degrees level 3: 60 degrees level 4: 65 degrees level 5: 70 degrees level 6: 80 degrees if the temperature gets above 90 degrees we throw a fault and drop into standby (with fault showing). Mike va3mw > On Sep 29, 2019, at 10:38 PM, Andy Durbin wrote: > > The KPA500 offers a minimum fan speed setting which is settable by menu or > serial command. Some posters have advocated setting a minimum fan speed > higher than zero, presumably thinking it offers some advantage in thermal > management. > > Does anyone have any hard data that shows that the KPA500 runs cooler, or > with lower peak fan speed, when minimum fan speed is set above zero. > > Running a rigorous test may not be easy since it would seem to require the > same ambient temperature, same finals starting temperature, same TX periods, > and same antenna system load. > > I'm curious because, before CQ-WW-RTTY I configured my KPA500 to set min fan > speed to 1 at start of TX and reset min speed to zero 30 seconds after stop > of TX. Of course the fans ran faster than min speed during TX but I don't > have any feel for whether the higher speeds were any more protracted than > before the min speed change. > > Please share you experience of using min fan speed greater than zero, and any > data if you have it. > > 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 va...@portcredit.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] KPA500 - Advantage of min fan speed?
On 9/29/2019 7:38 PM, Andy Durbin wrote: Please share you experience of using min fan speed greater than zero, and any data if you have it. Lots of experience, but I've never bothered to take data. I used my KPA500 (replaced by KPA1500) a lot for WSJT modes on 6M. The KPA500 fan gets pretty loud after 15-20 minutes of near constant calling on FT8 or MSK144, but it takes a lot longer to get that way if a higher minimum speed is set. The KPA1500 works the same way, except that it gets a LOT LOUDER at LOT sooner. Neither amp is noisy enough to be an issue on CW or SSB, even with fairly heavy HF contest operation. I used the KPA1500 for the first time in a RTTY contest this weekend. I started hearing the fans speed up after 10-15 minutes of CQing with not many responses, but they never got anywhere near the SCREAMING level they hit with digital on 6M. The fan noise is tolerable because I do 100% of my CW and SSB operation with headphones, and for SSB it's a Yamaha CM500 with an attached boom mic. And for serious RTTY contesting, I'm running SO2R, wearing a headset with one ear dedicated to each radio to help me keep track of what's happening on each radio. The significance of 6M is that both amps are least efficient there. 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
[Elecraft] KPA500 - Advantage of min fan speed?
The KPA500 offers a minimum fan speed setting which is settable by menu or serial command. Some posters have advocated setting a minimum fan speed higher than zero, presumably thinking it offers some advantage in thermal management. Does anyone have any hard data that shows that the KPA500 runs cooler, or with lower peak fan speed, when minimum fan speed is set above zero. Running a rigorous test may not be easy since it would seem to require the same ambient temperature, same finals starting temperature, same TX periods, and same antenna system load. I'm curious because, before CQ-WW-RTTY I configured my KPA500 to set min fan speed to 1 at start of TX and reset min speed to zero 30 seconds after stop of TX. Of course the fans ran faster than min speed during TX but I don't have any feel for whether the higher speeds were any more protracted than before the min speed change. Please share you experience of using min fan speed greater than zero, and any data if you have it. 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] FS PR6 Preamp/KXV3A
PR-6 6M receive preamp with power cable/accessory plug and BNC adapters including KXV3A that must be installed in the K3 to use the PR-6. Amp can be used separately with another receiver. Both $75 cor offer, shipped Priority Mail. USPS money order or cleared personal check preferred. Please contact me off the list. Thanks es 73, Elliott WA6TLA __ 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] KX3; Firmware Update
Hi, I'm waiting for new firmware for the KX3. For example, there still is a "tbd" in the SMTR Mode menu... and this after so many years :-( 73 de Uwe, DL4AC __ 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] Sunday Net
Here is the log from today's net. Thanks to K1NW, Brian, N4NRW, Roger, KF7ZN, Ron, a first time check in, and Steve, WM6P for their help relaying stations into the net. Elecraft SSB Net 9-29-2019 WB9JNZ Eric IL K3 4017 NetControl K8NU/4 Carl OH KenwoodTS 590 K1NW Brian RI K3 4974 Relay Station N6PGQ Bob CA K3 5891 N4NRW Roger SC K3 1318 Relay station AI6KU Bob CA KX3 10068 W7OL Alan OR Yaesu FT 3000 formerly K7FH KF7ZN Ron UT K3S 10832 Relay station, 1sttime check in KO5V Jim NM K2/100 7255 W1NGA AL CO K3 5765 AE1E Ken NM K3S 11611 W7REK Glenn AZ K3 2843 KE5VDT Roger TX K3 6054 NS7P Phil OR K3 1826 WM6P Steve GA K3S 11453 W5RG Bob FL K3 1440 K4FBI Mike VA K3S 11414 K7JG John WA KX3 3519 N9SRA Steve IL ICOM 7600 W0LEN Len IL ICOM 730 1st time check in K7BRR Bill AZ K3S 10939 KB2KWD Mike AK TEN TEC PARAGON __ 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] KX2 Gen coverage rcvr
I've found the memories to be a good way of band hopping. I have all the ham bands /modes programmed plus WWVs and the centers of SWBC bands. This is easy to do with the K3 memory editor download from the Elecraft website. Works for K3, K3s, KX3 and KX2. 73, Brian, K0DTJ > On Sep 29, 2019, at 08:51, Bob Conder via Elecraft > wrote: > > Really basic question: what's the best way to set up the KX2 as a general > coverage receiver?TNX de K4RLC Bob > __ > 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 huntin...@coastside.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
[Elecraft] Using transverter band displays as a way to set up SWL bands
Walter, If you have specific SWL bands you'd like to listen to that are at 6 MHz or above, you can use the KX2's transverter band display feature for this purpose. They'll appear as bands "XVTR 1" etc. above the regular bands as you cycle through them with the BAND switch. For example, suppose you wanted an SWL band covering approximately 6 to 8 MHz. Set up MENU:XV1 ON = YES, MENU:XV1 RF to 7, and MENU:XV1 IF to 7. This creates a virtual band display with an "IF" of 7 MHz. Since the "RF" is also specified as 7 MHz, the difference between the two will be 0. Just use BAND to select "XVTR 1" to tune this range. This will not have any effect on the normal 40 meter band settings. This technique is limited to bands close to those offered as IF selections (7, 14, 21, and 28 MHz). The same trick will work on the KX3 and K3. 73, Wayne N6K > On Sep 29, 2019, at 9:26 AM, Walter Underwood wrote: > > I miss the “GEN” band on the IC-756 that I used to have. It was nice to be > able to check out WWV or Radio Havana while leaving all the ham bands > untouched. It was a small thing but surprisingly convenient. > > wunder > K6WRU > Walter Underwood > CM87wj > http://observer.wunderwood.org/ (my blog) > >> On Sep 29, 2019, at 9:19 AM, Wayne Burdick wrote: >> >> Hi Bob, >> >> The KX2's RF band-pass filters cover all popular SWL bands. You can use >> direct frequency entry to jump to specific frequencies, or just tune the >> VFO. It can copy AM signals in either AM or SSB modes. Use the FIL switch to >> adjust the audio passband. >> >> You may want to set the VFO tuning rate (MENU:VFO CRS) to 5 or 10 kHz in AM >> mode. >> >> The KX2 also includes 100 frequency memories (with 5 character labels), 4 >> per-band memories, scanning, and channel hopping within grouped memories. >> All of these can be useful for general coverage. Refer to the owner's manual. >> >> Another feature unique is stereo audio. If you have AFX MD turned on, and >> you're using headphones or two external powered speakers, you'll get >> simulated stereo, which can be more pleasing to listen to than mono. >> >> The KX3 and K3S share all of the above features. >> >> 73, >> Wayne >> N6KR >> >> >>> On Sep 29, 2019, at 8:51 AM, Bob Conder via Elecraft >>> wrote: >>> >>> Really basic question: what's the best way to set up the KX2 as a general >>> coverage receiver?TNX de K4RLC Bob >> >> >> >> __ >> 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 n...@elecraft.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] KX2 Gen coverage rcvr
Wayne - thank you very much for your very detailed reply. Really enjoying the KX2. Have been running qrp portable from North Myrtle Beach, SC, near the ocean. Will be on 20 this afternoon and 40 tonight.73 Bob K4RLC On Sunday, September 29, 2019, 12:19:59 PM EDT, Wayne Burdick wrote: Hi Bob, The KX2's RF band-pass filters cover all popular SWL bands. You can use direct frequency entry to jump to specific frequencies, or just tune the VFO. It can copy AM signals in either AM or SSB modes. Use the FIL switch to adjust the audio passband. You may want to set the VFO tuning rate (MENU:VFO CRS) to 5 or 10 kHz in AM mode. The KX2 also includes 100 frequency memories (with 5 character labels), 4 per-band memories, scanning, and channel hopping within grouped memories. All of these can be useful for general coverage. Refer to the owner's manual. Another feature unique is stereo audio. If you have AFX MD turned on, and you're using headphones or two external powered speakers, you'll get simulated stereo, which can be more pleasing to listen to than mono. The KX3 and K3S share all of the above features. 73, Wayne N6KR > On Sep 29, 2019, at 8:51 AM, Bob Conder via Elecraft > wrote: > > Really basic question: what's the best way to set up the KX2 as a general > coverage receiver?TNX de K4RLC Bob __ 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] KX2 Gen coverage rcvr
I miss the “GEN” band on the IC-756 that I used to have. It was nice to be able to check out WWV or Radio Havana while leaving all the ham bands untouched. It was a small thing but surprisingly convenient. wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Sep 29, 2019, at 9:19 AM, Wayne Burdick wrote: > > Hi Bob, > > The KX2's RF band-pass filters cover all popular SWL bands. You can use > direct frequency entry to jump to specific frequencies, or just tune the VFO. > It can copy AM signals in either AM or SSB modes. Use the FIL switch to > adjust the audio passband. > > You may want to set the VFO tuning rate (MENU:VFO CRS) to 5 or 10 kHz in AM > mode. > > The KX2 also includes 100 frequency memories (with 5 character labels), 4 > per-band memories, scanning, and channel hopping within grouped memories. All > of these can be useful for general coverage. Refer to the owner's manual. > > Another feature unique is stereo audio. If you have AFX MD turned on, and > you're using headphones or two external powered speakers, you'll get > simulated stereo, which can be more pleasing to listen to than mono. > > The KX3 and K3S share all of the above features. > > 73, > Wayne > N6KR > > >> On Sep 29, 2019, at 8:51 AM, Bob Conder via Elecraft >> wrote: >> >> Really basic question: what's the best way to set up the KX2 as a general >> coverage receiver?TNX de K4RLC Bob > > > > __ > 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] KX2 Gen coverage rcvr
Hi Bob, The KX2's RF band-pass filters cover all popular SWL bands. You can use direct frequency entry to jump to specific frequencies, or just tune the VFO. It can copy AM signals in either AM or SSB modes. Use the FIL switch to adjust the audio passband. You may want to set the VFO tuning rate (MENU:VFO CRS) to 5 or 10 kHz in AM mode. The KX2 also includes 100 frequency memories (with 5 character labels), 4 per-band memories, scanning, and channel hopping within grouped memories. All of these can be useful for general coverage. Refer to the owner's manual. Another feature unique is stereo audio. If you have AFX MD turned on, and you're using headphones or two external powered speakers, you'll get simulated stereo, which can be more pleasing to listen to than mono. The KX3 and K3S share all of the above features. 73, Wayne N6KR > On Sep 29, 2019, at 8:51 AM, Bob Conder via Elecraft > wrote: > > Really basic question: what's the best way to set up the KX2 as a general > coverage receiver?TNX de K4RLC Bob __ 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] KX2 Gen coverage rcvr
Really basic question: what's the best way to set up the KX2 as a general coverage receiver?TNX de K4RLC Bob __ 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] K3S Wont TX in RTTY
For some reason I can't find the answer to, my K3S won't go in to TX when in RTTY. It does for FT8 and all other modes but when it comes to FSK the PTT is inhibited for some reason. When in TX Data mode for RTTY I press the XMT button and I get N/A on the display. I'm sure it's some setting but which one? Pete, W1RM w...@comcast.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
[Elecraft] K3 LPA failure, again
Martin, Thanks for posting your findings and solution. 73 Ben W4SC 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
Re: [Elecraft] Audio Hum in data mode
Thanks for sharing and glad you were able to resolve the issue. That must have been one heck of a magnetic field. Bob, K4TAX Sent from my iPhone > On Sep 29, 2019, at 8:18 AM, Conrad PA5Y wrote: > > Gentlemen I have cured the problem. > > The answer came as a result of Jim's comments. > > 1. It was magnetic and it was hum > 2. All my shack has a single ring main and share a common earth, so it was > nothing to do with that > 3. 'Magnetic coupling is proportional to the area of the loop', this pointed > to the problem > > So let me describe what the problem was. Some time ago I bought a lot of > benches and cables from a company that made video equipment for the broadcast > industry. They were down-sizing and moving premises. Some of the cables were > dual link DVI cables, they were quite long and looked to be of the highest > quality. I was the length of the cable that caused the problem. I was using > it with a large monitor to get full resolution. I also had this monitor in > portrait mode - I can swivel it. By going to landscape mode and changing to > an HDMI cable, being much more careful with the supply routing and video > routing I was able to eradicate the problem. The longer original monitor > cable was picking up magnetic fields and coupling into the audio transformers. > > The hum is now inaudible, I should mention that I was running the 2nd RX > without AGC and used an attenuator so that the receiver was close to > clipping. This shows up any nasties on TX audio. If I put the AGC on this > masks such problems to some extent. Now there is nothing audible. > > 73 > > Conrad PA5Y > > > > > -Original Message- > From: elecraft-boun...@mailman.qth.net On > Behalf Of Jim Brown > Sent: 28 September 2019 03:32 > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] Audio Hum in TX Data Mode > >> On 9/27/2019 2:26 PM, Conrad PA5Y wrote: >> What did make a difference was moving the radio away from sources of >> magnetic fields such as monitors. > > First, an important clarification -- is it HUM (pure 50 Hz) or BUZZ > (harmonics of 50 Hz)? You description sounds like hum. The important thing > is that the causes are different. Hum is, indeed, magnetic coupling of the 50 > Hz field to some loop in the audio wiring. > > Magnetic coupling is proportional to the area of the loop. Suggestions. > First, get power for all interconnected equipment from outlets that share the > same protective earth. Second, bond chassis-chassis of every piece of > equipment in the audio interconnection path. Third, try to figure out what > the loop is that is doing the coupling and reduce its area. In some recording > studios where a strong magnetic field exists, the solution is to run shielded > twisted pair audio wiring in close proximity to power wiring. > > Also try to find or eliminate the source of the magnetic field. In North > America, neutral must be bonded to earth at one, and ONLY one point, usually > where it enters a building. A second bond between neutral and the same > protective earth can create a magnetic field. Is it possible that there is a > second bond somewhere in your system, perhaps associated with power to your > EME setup? > > The I/O board for the original K3 uses un-shielded audio transformers that > are a sitting duck for magnetic fields. My neighbor K6XX is an engineer at > Elecraft. When he was testing an early K3 prototype, he set it up almost on > top of his 1.5 kW power amp. When he tried to run RTTY, The AF circuitry was > set into regeneration by the 60 Hz field! The solution I suggested was a > steep high pass filter for AFSK-A, and that solved it. > > Many years ago, a Chicago FM station whose engineers I knew well moved their > studios from a location downtown to another location that is common to a TV > studio with whom they had a relationship. When they first moved in, a strong > magnetic field was coupling into the mic input transformers of their music > mixing desks. The cause was an error in mains wiring -- the neutral for the > distribution panel for the FM studio was exchanged with the neutral for a > distribution panel feeding lighting in a different part of the building. > > 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 g0...@g0ruz.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 > Mess
Re: [Elecraft] Audio Hum in data mode
Forgot to mention that landscape mode moves the internal PSU of the monitor through 90 degrees and further away from any cables that are related to the other radios. 73 Conrad -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Conrad PA5Y Sent: 29 September 2019 15:18 To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Audio Hum in data mode Gentlemen I have cured the problem. The answer came as a result of Jim's comments. 1. It was magnetic and it was hum 2. All my shack has a single ring main and share a common earth, so it was nothing to do with that 3. 'Magnetic coupling is proportional to the area of the loop', this pointed to the problem So let me describe what the problem was. Some time ago I bought a lot of benches and cables from a company that made video equipment for the broadcast industry. They were down-sizing and moving premises. Some of the cables were dual link DVI cables, they were quite long and looked to be of the highest quality. I was the length of the cable that caused the problem. I was using it with a large monitor to get full resolution. I also had this monitor in portrait mode - I can swivel it. By going to landscape mode and changing to an HDMI cable, being much more careful with the supply routing and video routing I was able to eradicate the problem. The longer original monitor cable was picking up magnetic fields and coupling into the audio transformers. The hum is now inaudible, I should mention that I was running the 2nd RX without AGC and used an attenuator so that the receiver was close to clipping. This shows up any nasties on TX audio. If I put the AGC on this masks such problems to some extent. Now there is nothing audible. 73 Conrad PA5Y -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Jim Brown Sent: 28 September 2019 03:32 To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Audio Hum in TX Data Mode On 9/27/2019 2:26 PM, Conrad PA5Y wrote: > What did make a difference was moving the radio away from sources of magnetic > fields such as monitors. First, an important clarification -- is it HUM (pure 50 Hz) or BUZZ (harmonics of 50 Hz)? You description sounds like hum. The important thing is that the causes are different. Hum is, indeed, magnetic coupling of the 50 Hz field to some loop in the audio wiring. Magnetic coupling is proportional to the area of the loop. Suggestions. First, get power for all interconnected equipment from outlets that share the same protective earth. Second, bond chassis-chassis of every piece of equipment in the audio interconnection path. Third, try to figure out what the loop is that is doing the coupling and reduce its area. In some recording studios where a strong magnetic field exists, the solution is to run shielded twisted pair audio wiring in close proximity to power wiring. Also try to find or eliminate the source of the magnetic field. In North America, neutral must be bonded to earth at one, and ONLY one point, usually where it enters a building. A second bond between neutral and the same protective earth can create a magnetic field. Is it possible that there is a second bond somewhere in your system, perhaps associated with power to your EME setup? The I/O board for the original K3 uses un-shielded audio transformers that are a sitting duck for magnetic fields. My neighbor K6XX is an engineer at Elecraft. When he was testing an early K3 prototype, he set it up almost on top of his 1.5 kW power amp. When he tried to run RTTY, The AF circuitry was set into regeneration by the 60 Hz field! The solution I suggested was a steep high pass filter for AFSK-A, and that solved it. Many years ago, a Chicago FM station whose engineers I knew well moved their studios from a location downtown to another location that is common to a TV studio with whom they had a relationship. When they first moved in, a strong magnetic field was coupling into the mic input transformers of their music mixing desks. The cause was an error in mains wiring -- the neutral for the distribution panel for the FM studio was exchanged with the neutral for a distribution panel feeding lighting in a different part of the building. 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 g0...@g0ruz.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 g0
Re: [Elecraft] Audio Hum in data mode
Gentlemen I have cured the problem. The answer came as a result of Jim's comments. 1. It was magnetic and it was hum 2. All my shack has a single ring main and share a common earth, so it was nothing to do with that 3. 'Magnetic coupling is proportional to the area of the loop', this pointed to the problem So let me describe what the problem was. Some time ago I bought a lot of benches and cables from a company that made video equipment for the broadcast industry. They were down-sizing and moving premises. Some of the cables were dual link DVI cables, they were quite long and looked to be of the highest quality. I was the length of the cable that caused the problem. I was using it with a large monitor to get full resolution. I also had this monitor in portrait mode - I can swivel it. By going to landscape mode and changing to an HDMI cable, being much more careful with the supply routing and video routing I was able to eradicate the problem. The longer original monitor cable was picking up magnetic fields and coupling into the audio transformers. The hum is now inaudible, I should mention that I was running the 2nd RX without AGC and used an attenuator so that the receiver was close to clipping. This shows up any nasties on TX audio. If I put the AGC on this masks such problems to some extent. Now there is nothing audible. 73 Conrad PA5Y -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Jim Brown Sent: 28 September 2019 03:32 To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Audio Hum in TX Data Mode On 9/27/2019 2:26 PM, Conrad PA5Y wrote: > What did make a difference was moving the radio away from sources of magnetic > fields such as monitors. First, an important clarification -- is it HUM (pure 50 Hz) or BUZZ (harmonics of 50 Hz)? You description sounds like hum. The important thing is that the causes are different. Hum is, indeed, magnetic coupling of the 50 Hz field to some loop in the audio wiring. Magnetic coupling is proportional to the area of the loop. Suggestions. First, get power for all interconnected equipment from outlets that share the same protective earth. Second, bond chassis-chassis of every piece of equipment in the audio interconnection path. Third, try to figure out what the loop is that is doing the coupling and reduce its area. In some recording studios where a strong magnetic field exists, the solution is to run shielded twisted pair audio wiring in close proximity to power wiring. Also try to find or eliminate the source of the magnetic field. In North America, neutral must be bonded to earth at one, and ONLY one point, usually where it enters a building. A second bond between neutral and the same protective earth can create a magnetic field. Is it possible that there is a second bond somewhere in your system, perhaps associated with power to your EME setup? The I/O board for the original K3 uses un-shielded audio transformers that are a sitting duck for magnetic fields. My neighbor K6XX is an engineer at Elecraft. When he was testing an early K3 prototype, he set it up almost on top of his 1.5 kW power amp. When he tried to run RTTY, The AF circuitry was set into regeneration by the 60 Hz field! The solution I suggested was a steep high pass filter for AFSK-A, and that solved it. Many years ago, a Chicago FM station whose engineers I knew well moved their studios from a location downtown to another location that is common to a TV studio with whom they had a relationship. When they first moved in, a strong magnetic field was coupling into the mic input transformers of their music mixing desks. The cause was an error in mains wiring -- the neutral for the distribution panel for the FM studio was exchanged with the neutral for a distribution panel feeding lighting in a different part of the building. 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 g0...@g0ruz.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] We Need More Power
On 27/09/2019 16:03, Bob McGraw K4TAX wrote: [Tedious eulogy snipped] QRP. It isn't big and it isn't clever. 73, Richard G4DYA __ 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
