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Tektronix 7L12
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hardyhansendk
Hi
I am trying to fix an tektronix 7L12 spectrum analyzer! When measuring a frquency-say 50Mhz-it is offset on screen--the zero hertz are shown clearly with same offset!. Have any off you some experience with this spectrum analyzer? Regards Hardy
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Miguel Work
Hi,
Do you have a button that said start / center above frequency indicator? -----Mensaje original----- De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de hardyhansendk via groups.io Enviado el: miércoles, 27 de enero de 2021 7:56 Para: TekScopes@groups.io Asunto: [TekScopes] Tektronix 7L12 Hi I am trying to fix an tektronix 7L12 spectrum analyzer! When measuring a frquency-say 50Mhz-it is offset on screen--the zero hertz are shown clearly with same offset!. Have any off you some experience with this spectrum analyzer? Regards Hardy Scanned by McAfee and confirmed virus-free. Find out more here: https://bit.ly/2zCJMrO
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On Wed, Jan 27, 2021 at 07:55 AM, hardyhansendk wrote:
Did you try adjusting the Horizontal Position knob, right side, in the middle? Raymond
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cmjones01
On Wed, Jan 27, 2021 at 3:13 PM Raymond Domp Frank <hewpatek@gmail.com> wrote:
On Wed, Jan 27, 2021 at 07:55 AM, hardyhansendk wrote:Also, on my 7L12, the MHz dial is really very approximate: it'sDid you try adjusting the Horizontal Position knob, right side, in the middle? usually within about 20MHz of the correct value, drifting somewhat as it warms up. Mine might be broken, of course, but it's always been like that since I've had it. Looking at how the whole thing works, I'm not surprised: it's just adjusting the front end YIG oscillator and there's nothing to correct it to a precise frequency. To see the 0Hz spike at the correct position on the screen, the MHz knob could be set anywhere between 9970-0030MHz in my experience. Use of the calibrator, or some knowledge of what frequency you're looking at, is really necessary. Chris
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On Wed, Jan 27, 2021 at 03:29 PM, cmjones01 wrote:
You're right of course, Chris, it's not a frequency meter. The specifications mention a readout accuracy of +/- (10 MHz + 1% of the dial readout). Raymond
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On Wed, Jan 27, 2021 at 07:55 AM, hardyhansendk wrote:
Are you using the calibrator (and horizontal adjustment) for setting/calibrating the horizontal position? The DC ("0 Hz") position is not useful for that. Use e.g. 50 MHz and always set dialing CW, since there is some play/hysteresis. Raymond
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hardyhansendk
Hi
Yes there are a start and center button Hardy -----Oprindelig meddelelse----- Fra: TekScopes@groups.io [mailto:TekScopes@groups.io] På vegne af Miguel Work Sendt: 27. januar 2021 14:42 Til: TekScopes@groups.io Emne: Re: [TekScopes] Tektronix 7L12 Hi, Do you have a button that said start / center above frequency indicator? -----Mensaje original----- De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de hardyhansendk via groups.io Enviado el: miércoles, 27 de enero de 2021 7:56 Para: TekScopes@groups.io Asunto: [TekScopes] Tektronix 7L12 Hi I am trying to fix an tektronix 7L12 spectrum analyzer! When measuring a frquency-say 50Mhz-it is offset on screen--the zero hertz are shown clearly with same offset!. Have any off you some experience with this spectrum analyzer? Regards Hardy Scanned by McAfee and confirmed virus-free. Find out more here: https://bit.ly/2zCJMrO -- Denne mail er kontrolleret for vira af AVG. http://www.avg.com
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hardyhansendk
Thanks Chris
Yes i guess you are right--it is not a accurate instrument--will try to align the 1 lo. Hardy -----Oprindelig meddelelse----- Fra: TekScopes@groups.io [mailto:TekScopes@groups.io] På vegne af cmjones01 Sendt: 27. januar 2021 15:30 Til: TekScopes@groups.io Emne: Re: [TekScopes] Tektronix 7L12 On Wed, Jan 27, 2021 at 3:13 PM Raymond Domp Frank <hewpatek@gmail.com> wrote: On Wed, Jan 27, 2021 at 07:55 AM, hardyhansendk wrote:Also, on my 7L12, the MHz dial is really very approximate: it'sDid you try adjusting the Horizontal Position knob, right side, in the middle? usually within about 20MHz of the correct value, drifting somewhat as it warms up. Mine might be broken, of course, but it's always been like that since I've had it. Looking at how the whole thing works, I'm not surprised: it's just adjusting the front end YIG oscillator and there's nothing to correct it to a precise frequency. To see the 0Hz spike at the correct position on the screen, the MHz knob could be set anywhere between 9970-0030MHz in my experience. Use of the calibrator, or some knowledge of what frequency you're looking at, is really necessary. Chris -- Denne mail er kontrolleret for vira af AVG. http://www.avg.com
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hardyhansendk
Hi Raymond
I use all of them cal-zero dc and external generator--all with same displayed offset frequency--wonder if one can adjust the first lo! hardy -----Oprindelig meddelelse----- Fra: TekScopes@groups.io [mailto:TekScopes@groups.io] På vegne af Raymond Domp Frank Sendt: 27. januar 2021 16:04 Til: TekScopes@groups.io Emne: Re: [TekScopes] Tektronix 7L12 On Wed, Jan 27, 2021 at 07:55 AM, hardyhansendk wrote: Are you using the calibrator (and horizontal adjustment) for setting/calibrating the horizontal position? The DC ("0 Hz") position is not useful for that. Use e.g. 50 MHz and always set dialing CW, since there is some play/hysteresis. Raymond -- Denne mail er kontrolleret for vira af AVG. http://www.avg.com
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