Buck, Good suggestion but that was one of the things that I checked earlier this morning when I had the hum on the mic. Both compression level and mic gain were the same that they always have been.
73, phil, K7PEH On Jan 13, 2012, at 12:02 PM, Buck - k4ia wrote: > Is it possible that in setting the power level, you accidentally turned > up the compression? (they are on the same knob). If the compression is > too high it will make a rushing, buzzing sound on the audio > > Buck > k4ia > > > On 1/13/2012 2:09 PM, Phil Hystad wrote: >> Ron, >> >> OK, now it appears I was mistaken when I said that that the hum was in both >> mics. I think I flubbed something up in my previous test due to the way >> that the macros are assigned to keys which led me to thinking that the hum >> occurred in both mics. But, I learned something in this... >> >> One, don't try to use one of your macro assigned keys (in my case M2 and M1) >> while in the menu because that merely reassigns the key to the new menu >> entry. I made this mistake several times this morning. But, when I >> discovered it and then reset my macro definitions, I rediscovered that the >> HUM occurs in the front panel MH2 hand held mic only. I did this test >> several times to make sure I was not confusing things. >> >> I discovered something else that I did not know before. PTT is actuated by >> any of the methods of PTT. So, when I thought I had the headphones CM500 >> mic enabled I used my foot switch for push to talk and since that worked for >> some dumb reason I was thinking I had successfully switched from front panel >> to rear panel. But, I had not. I also discovered that I could use the hand >> mic (front panel) PTT switch even though my rear panel mic was being used. >> Now, after I discovered this, I realize that it is obvious but something >> that lead to my confusion. >> >> So, the problem occurs on the FRONT PANEL mic only and not the rear panel. >> And, the problem occurs when the K3 is in TOTAL isolation from all AC >> sources except for possibly me. I mean, I am holding the mic but then I >> don't think that is a cause of the hum because I tried it with a insulated >> hand and it still caused the hum on the front panel mic. >> >> I doubt that this is caused by wall-outlet type AC because I have erased all >> AC for some of my tests. And, besides, this problem seemed to occur .... >> >> OK, while writing that last sentence something occurred to me. Another >> change I had made on Wednesday after I had my good audio reports on the MH2 >> front panel mic was that I set the configuration for the band specific power >> levels to work with the KPA500. So, I just now went to test the mic and >> change that setting around but the hum is gone. >> >> I repeat, the hum is gone from the front panel mic. I now can't test the >> band specific power menu setting because I have no problem. >> >> But, I have a suspicion as to the cause now and I am going to do some other >> experiments. >> >> 73, phil >> >> >> On Jan 13, 2012, at 10:15 AM, Ron D'Eau Claire wrote: >> >>> Yeah, Phil, two mics doing it eliminates the easy idea of a bad wire in one >>> of them. >>> >>> When switching mics, be sure to physically disconnect the one you are not >>> using. An ungrounded mic hot lead might introduce hum, even if you have the >>> other mic enabled. >>> >>> Hand effects suggest a ground loop- either AC or RF. Being in TEST mode >>> eliminates RF, since you aren't making any. >>> >>> I'd start disconnecting things one at a time. If the hum is still there with >>> everything but the mic and power supply connected, you can be sure it's not >>> in the external gear. >>> >>> Do you have another power supply you can substitute? All it needs to do is >>> provide enough current for receive, since you are "transmitting" in TEST >>> mode. One possibility is that you'd lost filtering in the power supply. That >>> can produce different levels of hum from different mics, depending upon the >>> gain settings, etc. >>> >>> If it's clean on the alternate power supply, that leaves ONLY the K3, of >>> course. >>> >>> 73, >>> >>> Ron AC7AC >>> >>> -----Original Message----- >>> From: Phil Hystad [mailto:[email protected]] >>> Sent: Friday, January 13, 2012 9:21 AM >>> To: Ron D'Eau Claire >>> Cc: 'Elecraft List' >>> Subject: Re: [Elecraft] K3 Hum on Audio... >>> >>> Ron, >>> >>> I have been able to do more tests. Unfortunately, it is in both mics but >>> not as strong in the Yamaha CM500 mic as in the MH2 but it is present. >>> >>> This morning I double checked all connections (most in the back). This >>> includes the key out to the KPA500, the plugs for the cm500, the external >>> speaker, my foot PTT switch, and even the svga cable to the KPA500. Nuts, >>> have not tested the serial port yet. However, absolutely no difference in >>> behavior. I can hear the hum on the speaker when I have the monitor gain >>> cranked up a little bit and keying the mic in Test mode. >>> >>> If I lay my hand on the top of the K3 the hum disappears. If I lay my hand >>> on the P3 sitting next to K3 the hum disappears but not as much. And, I can >>> do the same with other grounded equipment. I have checked my grounds and >>> they all seem to be pretty good. >>> >>> So, I am at a loss as to what to try next. This seemed to start on its own >>> Wednesday afternoon after my last SSB QSO. I say that because after that >>> QSO, I turned the rigs off and then the next day (Thursday, yesterday) I >>> turned the rigs on and the hum was there on my first SSB QSO at 6:30 PM. >>> >>> It sure seems like a grounding problem but I am not sure where to check >>> next. Also, this problem arose mysteriously close to me setting up the >>> KPA500 which I put on the air for the first time Wednesday early afternoon, >>> CW first and then a few SSB QSOs and I got good audio reports from both of >>> those QSOs. The hum though is definite, if someone were listening to my >>> audio with this hum they would hear it. >>> >>> 73, phil, K7PEH >>> >>> >>> On Jan 13, 2012, at 8:12 AM, Ron D'Eau Claire wrote: >>> >>>> Since it goes away when changing mics, it sounds a lot like a broken >>>> connection in the microphone connector. I used to fix those by the dozens >>> on >>>> shipboard VHF radios, equipped with hand-held mics. The complaint would be >>>> transmitting hum, no audio, or no PTT action, depending upon which wire >>>> broke. >>>> >>>> Usually the break was at the connector, but sometimes it's in the mic, >>>> depending upon which end had the best strain relief. Even found a broken >>>> wire inside the cable on rare occasions. >>>> >>>> 73, >>>> >>>> Ron AC7AC >>>> >>>> -----Original Message----- >>>> Subject: [Elecraft] K3 Hum on Audio... >>>> >>>> When the sun rose today and it seems that my K3 decided to put some hum on >>>> my audio. During a quick SSB contact tonight on 80 meters I was told >>> there >>>> was hum on my audio. This surprised me because yesterday I was involved >>> in >>>> two different SSB QSOs where I was particularly interested in audio >>> reports >>>> because I had just put the KPA500 on the air and wanted to know how it >>>> sounds. The audio reports yesterday, two different QSOs, were excellent. >>>> In fact one person wanted to know the rig because he said it sounded >>>> exceptional. >>>> >>>> Well, tonight, I get a report of what sounds like (the other guy reported) >>>> 60 cycle hum on my audio. Now, absolutely NOTHING is different from >>>> yesterday, same configuration and all. So, I am thinking maybe it has >>>> something to do with the KPA500. So, I put that in Standby and the hum is >>>> still there on the audio. The mic is the MH2 hand mic plugged into the >>>> front of the K3. >>>> >>>> So, I switch to my Yamaha CM500 headset and mic plugged into the rear of >>> the >>>> K3. No hum on that. So, the hum seems to do with the MH2 or maybe the >>>> front panel connection or something else. >>>> >>>> Does anyone know of what would cause this sudden thing and where I might >>> go >>>> to scope out the problem? I would be more suspicious if it were some rig >>>> that was new to me, or some mic that was new or something. But, it is not >>>> new and until now I have always had excellent reports. Like I said, >>>> yesterday the KPA500 was put on the air for the first time but the reports >>>> were excellent reports on audio, this problem appeared today in fact, >>> about >>>> 30 minutes ago. I turned the rig on at 6:15 PM and had the first QSO >>> where >>>> the hum was reported at 6:25 PM. >>>> >>>> 73, phil, K7PEH >>>> >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[email protected] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
