K2 birdie at 28.265 MHz
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Does anyone know what causes this one. I have just about every option
installed including the KPA100. Would like to get rid of it if possible (S5 on the meter with a 1KHz tone). Thanks, MIchael _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: K2 birdie at 28.265 MHz
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Michael asked:
Does anyone know what causes this one. I have just about every option installed including the KPA100. Would like to get rid of it if possible (S5 on the meter with a 1KHz tone). ---------------------------------------------- My K2/100 shows it at 28264.50, about S3 with the preamp turned on. The frequency shifts slightly when the PA is enabled or disabled using the secondary menu. Seventh harmonic of the 4 MHz oscillator in the KPA100 perhaps? The frequency of that oscillator is not critical, but I don't know how far you can shift it using the trimmer cap. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 birdie at 28.265 MHz
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In reply to this post by N2ZDB-2
Michael,
My K2 has a birdie a few kHz higher which is caused by one of the receiver's spurious responses hearing the second harmonic of the KPA's HV bias oscillator, which in my KPA100 runs at 16.289 MHz. In my case the bias oscillator's harmonic gets to the receiver via the loudspeaker cable and the ribbon cable. What is the frequency of your KPA100's bias oscillator? 73, Geoff GM4ESD ----- Original Message ----- From: <[hidden email]> To: <[hidden email]> Sent: Saturday, July 16, 2005 3:59 PM Subject: [Elecraft] K2 birdie at 28.265 MHz > Does anyone know what causes this one. I have just about every option > installed including the KPA100. Would like to get rid of it if possible > (S5 on the > meter with a 1KHz tone). > > Thanks, > > MIchael _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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The (-) voltage generator (oscillator) in both the KIO2 or KPA100
generates a couple of weak birdies. They will move around a bit from K2 to K2, because the birdies are the result of high harmonics of this crystal oscillator mixing with high harmonics of the K2's VCO, and the fundamental crystal frequency has a tolerance of about +/- 0.5 kHz. We attempted to position the birdies in obscure parts of the spectrum. If the 10-meter birdie happens to hit close to a beacon that you want to monitor (28.265 is in the beacon area of the band), you should be able to move it a bit by changing one capacitor in the crystal oscillator. In the KIO2 case, the best choice would be C14. It is normally 56 pF, but paralleling another 10 pF across it should shift the oscillator a kHz or two, enough to move the signal off a CW beacon. The value of C14 isn't critical; it could change +/- 20% without significantly affecting output of the oscillator. 73, Wayne N6KR --- http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 birdie at 28.265 MHz
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Hi Wayne,
Many thanks. Believe me I understand the design problem!! I got rid of my birdie the 'hard way' by removing the loudspeaker circuit from the KPA100's PCB and hardwiring all the way from the K2's PCB speaker connector to the speaker, and clipping a ferrite sleeve onto the ribbon cable - I am sure that you know the type. The receiver's 10m spurious responses in my case were the 2Fspur = 3Fo - IF and another 3Fspur = 4Fo + IF further down the band, where Fspur = 32.578 MHz, the bias oscillator's second harmonic frequency. Both were in the region of 7db above noise floor in a bandwidth of 1500 Hz, with a dummy load on the antenna input. I have never detected the 5Fspur = 7Fo - IF potential birdie even in a 200 Hz bandwidth. I did the removal the 'hard way' to kill all birdies that involved the bias oscillator in one shot, as other bands were affected. Again, many thanks. 73, Geoff GM4ESD ----- Original Message ----- From: "wayne burdick" <[hidden email]> To: "Geoffrey Mackenzie-Kennedy" <[hidden email]> Cc: "Elecraft Discussion List" <[hidden email]>; <[hidden email]> Sent: Saturday, July 16, 2005 6:21 PM Subject: Re: K2 birdie at 28.265 MHz > The (-) voltage generator (oscillator) in both the KIO2 or KPA100 > generates a couple of weak birdies. They will move around a bit from K2 to > K2, because the birdies are the result of high harmonics of this crystal > oscillator mixing with high harmonics of the K2's VCO, and the fundamental > crystal frequency has a tolerance of about +/- 0.5 kHz. > > We attempted to position the birdies in obscure parts of the spectrum. If > the 10-meter birdie happens to hit close to a beacon that you want to > monitor (28.265 is in the beacon area of the band), you should be able to > move it a bit by changing one capacitor in the crystal oscillator. In the > KIO2 case, the best choice would be C14. It is normally 56 pF, but > paralleling another 10 pF across it should shift the oscillator a kHz or > two, enough to move the signal off a CW beacon. The value of C14 isn't > critical; it could change +/- 20% without significantly affecting output > of the oscillator. > > 73, > Wayne > N6KR > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Congrats Geoff!
After a long time some usefull info between tons of knobs,brocoli ecc... stuff. S55M-Adi ----- Original Message ----- From: "Geoffrey Mackenzie-Kennedy" <[hidden email]> To: "wayne burdick" <[hidden email]> Cc: "Elecraft Discussion List" <[hidden email]> Sent: Saturday, July 16, 2005 9:17 PM Subject: [Elecraft] Re: K2 birdie at 28.265 MHz > Hi Wayne, > > Many thanks. Believe me I understand the design problem!! I got rid of my > birdie the 'hard way' by removing the loudspeaker circuit from the KPA100's > PCB and hardwiring all the way from the K2's PCB speaker connector to the > speaker, and clipping a ferrite sleeve onto the ribbon cable - I am sure > that you know the type. The receiver's 10m spurious responses in my case > were the 2Fspur = 3Fo - IF and another 3Fspur = 4Fo + IF further down the > band, where Fspur = 32.578 MHz, the bias oscillator's second harmonic > frequency. Both were in the region of 7db above noise floor in a bandwidth > of 1500 Hz, with a dummy load on the antenna input. I have never detected > the 5Fspur = 7Fo - IF potential birdie even in a 200 Hz bandwidth. > > I did the removal the 'hard way' to kill all birdies that involved the > oscillator in one shot, as other bands were affected. > > Again, many thanks. > > 73, > Geoff > GM4ESD > > > ----- Original Message ----- > From: "wayne burdick" <[hidden email]> > To: "Geoffrey Mackenzie-Kennedy" <[hidden email]> > Cc: "Elecraft Discussion List" <[hidden email]>; <[hidden email]> > Sent: Saturday, July 16, 2005 6:21 PM > Subject: Re: K2 birdie at 28.265 MHz > > > > The (-) voltage generator (oscillator) in both the KIO2 or KPA100 > > generates a couple of weak birdies. They will move around a bit from K2 > > K2, because the birdies are the result of high harmonics of this crystal > > oscillator mixing with high harmonics of the K2's VCO, and the fundamental > > crystal frequency has a tolerance of about +/- 0.5 kHz. > > > > We attempted to position the birdies in obscure parts of the spectrum. If > > the 10-meter birdie happens to hit close to a beacon that you want to > > monitor (28.265 is in the beacon area of the band), you should be able to > > move it a bit by changing one capacitor in the crystal oscillator. In the > > KIO2 case, the best choice would be C14. It is normally 56 pF, but > > paralleling another 10 pF across it should shift the oscillator a kHz or > > two, enough to move the signal off a CW beacon. The value of C14 isn't > > critical; it could change +/- 20% without significantly affecting output > > of the oscillator. > > > > 73, > > Wayne > > N6KR > > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: Re: K2 birdie at 28.265 MHz
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Hi Adi,
Thank you, but there has been a lot of very interesting discussion about many things, no? I have learned a lot about 'grounds' recently, for example. Will contact you off list to catch up with your project. 73, Geoff GM4ESD ----- Original Message ----- From: "S55M" <[hidden email]> To: "Geoffrey Mackenzie-Kennedy" <[hidden email]>; "Elecraft Discussion List" <[hidden email]> Sent: Saturday, July 16, 2005 8:26 PM Subject: Re: [Elecraft] Re: K2 birdie at 28.265 MHz > Congrats Geoff! > > After a long time some usefull info between tons of knobs,brocoli ecc... > stuff. > > S55M-Adi > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: Re: K2 birdie at 28.265 MHz
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In reply to this post by S55M
Thanks for your technical information Geoff.
I was so comatose that I nearly missed your important mail. 73 Stewart G3RXQ On Sat, 16 Jul 2005 21:26:20 +0200, S55M wrote: > Congrats Geoff! > > After a long time some usefull info between tons of knobs,brocoli ecc... > stuff. > > S55M-Adi > ----- Original Message ----- > From: "Geoffrey Mackenzie-Kennedy" <[hidden email]> > To: "wayne burdick" <[hidden email]> > Cc: "Elecraft Discussion List" <[hidden email]> > Sent: Saturday, July 16, 2005 9:17 PM > Subject: [Elecraft] Re: K2 birdie at 28.265 MHz > > >> Hi Wayne, >> >> Many thanks. Believe me I understand the design problem!! I got rid of my >> birdie the 'hard way' by removing the loudspeaker circuit from the > KPA100's >> PCB and hardwiring all the way from the K2's PCB speaker connector to the >> speaker, and clipping a ferrite sleeve onto the ribbon cable - I am sure >> that you know the type. The receiver's 10m spurious responses in my case >> were the 2Fspur = 3Fo - IF and another 3Fspur = 4Fo + IF further down the >> band, where Fspur = 32.578 MHz, the bias oscillator's second harmonic >> frequency. Both were in the region of 7db above noise floor in a bandwidth >> of 1500 Hz, with a dummy load on the antenna input. I have never detected >> the 5Fspur = 7Fo - IF potential birdie even in a 200 Hz bandwidth. >> >> I did the removal the 'hard way' to kill all birdies that involved the > bias >> oscillator in one shot, as other bands were affected. >> >> Again, many thanks. >> >> 73, >> Geoff >> GM4ESD >> >> >> ----- Original Message ----- >> From: "wayne burdick" <[hidden email]> >> To: "Geoffrey Mackenzie-Kennedy" <[hidden email]> >> Cc: "Elecraft Discussion List" <[hidden email]> <[hidden email]> >> Sent: Saturday, July 16, 2005 6:21 PM >> Subject: Re: K2 birdie at 28.265 MHz >> >> >>> The (-) voltage generator (oscillator) in both the KIO2 or KPA100 >>> generates a couple of weak birdies. They will move around a bit from K2 > to >>> K2, because the birdies are the result of high harmonics of this crystal >>> oscillator mixing with high harmonics of the K2's VCO, and the > fundamental >>> crystal frequency has a tolerance of about +/- 0.5 kHz. >>> >>> We attempted to position the birdies in obscure parts of the spectrum. > If >>> the 10-meter birdie happens to hit close to a beacon that you want to >>> monitor (28.265 is in the beacon area of the band), you should be able > to >>> move it a bit by changing one capacitor in the crystal oscillator. In > the >>> KIO2 case, the best choice would be C14. It is normally 56 pF, but >>> paralleling another 10 pF across it should shift the oscillator a kHz or >>> two, enough to move the signal off a CW beacon. The value of C14 isn't >>> critical; it could change +/- 20% without significantly affecting output >>> of the oscillator. >>> >>> 73, >>> Wayne >>> N6KR >>> >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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