Re: K1 - VFO frequency range
Posted by
Cameron Francey on
May 25, 2017; 2:56am
URL: http://elecraft.85.s1.nabble.com/K1-VFO-frequency-range-tp7631062p7631090.html
Just as an additional note. I built two K1's last year and even though I wound the turns for L1 so they were really tight as I found from experience its much easier to spread them out a bit than to compress them again. In both K1's I actually had to remove one turn to get the VFO low enough. The manual does mention this may be needed.
Just though I'd bring that up since I had to do that fairly recently.
Cameron - AF7DK/GM7LQR
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From: Elecraft <
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Sent: Wednesday, May 24, 2017 9:04 AM
To: roney;
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Subject: Re: [Elecraft] K1 - VFO frequency range
I assume you have already calibrated the LCD display on each band using the OCF menue function. That makes the LCD indicate the actual transmitter output frequency, This display calibration for each band must be performed before adjustment of where the low end of each band starts.
Because the K1 has no way of adjusting the oscillation frequency of the individual heterodyne crystals on the filter board, the only band edge adjustment possible is accomplished by altering the VFO frequency. That affects both bands equally.
Your data show the K1 tuning band is too low by about 5.2 kHz. The VFO SUBTRACTS from the heterodyne crystal frequency, so to RAISE the K1 frequency of operation you must LOWER the VFO frequency by squeezing CLOSER together some of the turns on the RF board L1 VFO toroid. It won't require much. Try that until the low end of 80m indicates about 3499.0 kHz on the LCD. That 80m L1 adjustment will also bring the low end of 15m to about 20996.1 kHz. That will be the closest you'll get on 15m. If you adjusted L1 until 15m starts at 20999.0, then 80m will start at 3501.9 kHz. You'll have lost some low end 80m coverage.
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