I completed my K1 assembly/alignment/testing after about 27 hours. A
couple of those hours were spent dealing with the periodic noise burst on
RX.
I'm happy to report, that with the addition of a couple of 0.47uF caps on
the 6A and 6B power supply rails, the periodic noise burst signal level was
Great advice, Don. I will try that soon.
The noise is raspy alnost static like. Not a ticking like you would expect
from digital noise.
I have mechanically probed every component lead and cant cause the noise
that way which I would expect from any intermittant connection. Nor does
rapping hard
w <k...@arrl.net>, Elecraft <Elecraft@mailman.qth.net>
>Subject: Re: [Elecraft] [K1] Internal Noise Bursts every 12 seconds or
> so
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Subject: Re: [Elecraft] [K1] Internal Noise Bursts every 12 seconds or
so
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Great advice, Don. I will t
Thanks for the ideas, Mike!
Well I can rule out the Filter Board, as the noise is still there when the
Filter Board is removed.
I hoped I could remove the CPU to see if there was an issue there, but with
the CPU gone, the audio is eliminated (probably need to pull something high
or low to get
Bob wrote:
> In looking over the Front Panel Schematic quickly, my attention was
> drawn to the 6 volt power supply generated on the Front Panel ("6A")
> and distributed to several high gain parts of the RF board. Any noise
> on 6A is going to be an issue. I also noted that there is no
Bob,
Can you describe "noise burst" - is it more of a "tick", or if it is
longer, what is the approximate duration.
You will likely have to short the signal path at several points to
isolate it. One such point is the input to the product detector -
solder a jumper between pins 1 and 2 of T2.
I just completed assembly of a 30m/20m K1 up through the point of Receiver
calibration. Everythings has gone smoothly and all tests and alignment
steps were completed successfully. I can hear a 1 uV signal very clearly
on both bands.
However, there appears to be some internal periodic noise.
Bob,
That is not a normal situation for the K1.
The "standard" answer is that it is the result of a poor solder connection.
I cannot guess at where it could be other than to say due to the
periodic nature of the occurrence that it is associated with the MCU in
some manner.
So check the
Many thanks for the rapid reply, Don!
Good to know this isn't normal, and I will certainly follow your advice and
check the front panel assembly carefully, especially the solder. When I
initially checked things with an optical loop, the solder appeared to be
bright on both sides of the PCB (at
Bob wrote:
> Even though the second CPU on the filter board is mostly inactive, no
> telling what internal loops are going on that might result in it turning
> that 4 MHz resonator into a periodic signal.
In addition to the relays on the filter board itself, the PIC on the KFL1 board
controls
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