7000 receiver s meter calibration

WA2DVU
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Joined: Wed Nov 01, 2017 3:27 pm

7000 receiver s meter calibration

Postby WA2DVU » Sat Jun 27, 2020 10:45 pm

I was checking my 7000 and found that the S meter calibration is off. Listed below is what I found. Any info would be appreciated.

Signal Generator output = -73 dBm (50 mV S9) CW.
HP 3336A (-70 dBm + 3 dB pad)

Perseus reading = -73.2 dBm (AM 6 khz

Apache Reading -60 dBm (AM 8 khz)

Perseus reads what sig gen is putting out. Apache is reading +13 dB higher. Why?

73,

Bill WA2DVU - good on QRZ
Cape May, NJ
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w-u-2-o
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Joined: Fri Mar 10, 2017 1:47 pm

Re: 7000 receiver s meter calibration

Postby w-u-2-o » Sat Jun 27, 2020 11:47 pm

Mine was 6dB low: -73dBm in, -79dBm reported. So I ran the level calibration routine and now it's fine. Not terribly impressive, but no worse than any KenYaeWood radio. Input level verified using a modern Agilent analyzer with a recent, professional calibration.

As for why yours is off 13dB, regardless of what your other radio might report, when was the last time your thirty seven year old signal generator was in the cal lab?

If you trust your signal generator just run the level cal in Thetis.
WA2DVU
Posts: 42
Joined: Wed Nov 01, 2017 3:27 pm

Re: 7000 receiver s meter calibration

Postby WA2DVU » Sun Jun 28, 2020 1:21 am

I have several old sig gens (HP and Cushman) and they are all within 2 dB or so. One was at the cal lab a year ago. I did not know there was a level calibration routine. Where may it be? 73,

Bill, WA2DVU

Check my test bench out on QRZ.
WA2DVU
Posts: 42
Joined: Wed Nov 01, 2017 3:27 pm

Re: 7000 receiver s meter calibration

Postby WA2DVU » Sun Jun 28, 2020 11:04 am

Hi Scott,

I found the level calibration routine and took 5 minutes to calibrate the level. The 7000 and Thetis are amazing! My 2- HP 8640B, 2 - 3336B, and Cushman 5100A outputs are within +/- 1 db. Not bad for thirty-seven old gear. :D

Thank you for all of your help with the ANAN Group.

73,

Bill,WA2DVU
Cape May, NJ
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w-u-2-o
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Joined: Fri Mar 10, 2017 1:47 pm

Re: 7000 receiver s meter calibration

Postby w-u-2-o » Sun Jun 28, 2020 1:15 pm

Glad you found it, Bill. I'm still surprised it was off by that much.

Remember that all power levels displayed in PowerSDR and Thetis are referenced to the rear panel connector; the software add/subtracts for the preamp gain and any attenuation you may be using.

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