K1 4 bander issue

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K1 4 bander issue

ve3fal
I just acquired a K1 4 bander from a ham in Ottawa. It has 40,30,20 and 15 meters in it. All bands operate and function as they should except for 30 meters. Have done some searches on this possible issue but nothing solid as of yet. Anyone have a starting point where I might look to see or find the issue.

Cheers
Fred
VE3FAL

Sent from my iPhone
Fred VE3FAL/CIW649


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Re: K1 4 bander issue

Don Wilhelm
Fred,

If 40 meters works, then 30 should also.  They share the same low pass
filter and the inductors of the bandpass filter and Pre-Mixer bandpass
filter.

One possibility is that the crystal for 30 meters has gone bad.  You can
check for that with an oscilloscope or RF Probe at P1 pin 4.  You should
have at least 200mV peak to peak - which is 70mV RMS as seen on the RF
probe.

If you have oscillation at P1 pin 4, then the most common cause is that
30 meters has not been properly aligned.  Initially set C5, C6, CE and
CF to their mid-point then feed a strong signal into the antenna jack
with the K1 tuned to the frequency of the signal - you may have to hunt
around that frequency for the signal.
Then adjust the 30 meter trimmer capacitors to peak that signal.
After peaking in receive, set the OUT parameter to 1.5 watts and peak
those same trimmers on transmit.  If the power goes over 4 watts, stop
and reset OUT and then continue.

Once you have peaked 30 meters, you will have to peak the filters on 40
meters.

73,
Don W3FPR

On 8/4/2018 8:10 AM, Fred VE3FAL wrote:
> I just acquired a K1 4 bander from a ham in Ottawa. It has 40,30,20 and 15 meters in it. All bands operate and function as they should except for 30 meters. Have done some searches on this possible issue but nothing solid as of yet. Anyone have a starting point where I might look to see or find the issue.
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