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K1 - VFO frequency range

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roney

K1 - VFO frequency range

Hello, I just finished all tests and adjustments in my K1.
It works great. I have 2 filter band as 80m and 15m.
It's transmitting and receiving very well.

I followed all tests in:

VFO Range Test (Page 38):
VFO knob fully clockwise = 3.007 khz
VFO knob fully counterclockwise = 3.091 khz
VFO range = 84 khz

So I did Band Assignments (Page 39), etc, etc.

When seeing each band, my real ranges are:

80m: 3.493,8 to 3.577,6 mhz
15m: 20.990,9 to 21.074,6 mhz

I did not understand how to adjust these low and high limits. Should I
change some inductor turns ? or is there any menu adjust for these limits ?

Thanks for the help,
Roney Monte PY1ZB
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Don Wilhelm

Re: K1 - VFO frequency range

Roney,

There is no adjustment for individual bands.

If you have no other band boards, you can adjust the turns on L1 to
bring the lower end of 80 meters up to 3.500 MHz.

Normally, the VFO range is adjusted so that all bands will tune a bit
below the low frequency limit. This compensates for slight variation of
the exact frequency of the crystal on the band board.

If you have multiple band boards, check to see which band is closest to
the lower ham band and adjust the turns spacing of L1 to bring that band
near the lower edge of the band.

73,
Don W3FPR

On 5/24/2017 8:52 AM, roney wrote:

>
> So I did Band Assignments (Page 39), etc, etc.
>
> When seeing each band, my real ranges are:
>
> 80m: 3.493,8 to 3.577,6 mhz
> 15m: 20.990,9 to 21.074,6 mhz
>
> I did not understand how to adjust these low and high limits. Should I
> change some inductor turns ? or is there any menu adjust for these limits ?

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Mike Morrow-3

Re: K1 - VFO frequency range

In reply to this post by roney

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.

The K1 has been around since 2000, which is how long I've had #175. What's the serial on your recent K1? It's still a magnificent radio.

Mike / KK5F

-----Original Message-----

>From: roney <[hidden email]>
>Sent: May 24, 2017 7:52 AM
>To: [hidden email]
>Subject: [Elecraft] K1 - VFO frequency range
>
>Hello, I just finished all tests and adjustments in my K1.
>It works great. I have 2 filter band as 80m and 15m.
>It's transmitting and receiving very well.
>
>I followed all tests in:
>
>VFO Range Test (Page 38):
>VFO knob fully clockwise = 3.007 khz
>VFO knob fully counterclockwise = 3.091 khz
>VFO range = 84 khz
>
>So I did Band Assignments (Page 39), etc, etc.
>
>When seeing each band, my real ranges are:
>
>80m: 3.493,8 to 3.577,6 mhz
>15m: 20.990,9 to 21.074,6 mhz
>
>I did not understand how to adjust these low and high limits. Should I
>change some inductor turns ? or is there any menu adjust for these limits ?
>
>Thanks for the help,
>Roney Monte PY1ZB
>______________________________________________________________

Cameron Francey

Re: K1 - VFO frequency range

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

________________________________
From: Elecraft <[hidden email]> on behalf of Mike Morrow <[hidden email]>
Sent: Wednesday, May 24, 2017 9:04 AM
To: roney; [hidden email]
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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roney

Re: K1 - VFO frequency range

Hello Mike and Cameron, I appreciate your tips.
I adjusted the L1 inductor, getting 3.500,3 mhz and 20.098,2 mhz on VFO.
That was perfect to me.

(updating Cameron about the email)

So I moved the rig to another place and used another PSU (first using a
12,4v, and after using a 13.8v PSU)
I noticed that this minimum frequency changed to 3.501,2 mhz.
No problem about that.

Thanks and 73,
de PY1ZB, Roney

On Wed, May 24, 2017 at 11:56 PM, Cameron Francey <
[hidden email]> wrote:

> 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
>
>
>
>
> ------------------------------
> *From:* Elecraft <[hidden email]> on behalf of Mike
> Morrow <[hidden email]>
> *Sent:* Wednesday, May 24, 2017 9:04 AM
> *To:* roney; [hidden email]
> *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.
>
>