Brian,
Do you have the K2 completely built? or have you only built it up to the
point where you can receive 40 meters? I guess the point that you said
you had trouble adjusting the 40 meter BPF made me think the 10 MHz
oscillator might not work for you.
If you have it completely built, then the 10 MHz crystal will work. You
must select the 30 meter band.
However, because you have a transmit problem, you should use the
transmit signal tracing rather than receive - you will find the problem
source more easily, and the K2 itself provides the signals require for
signal tracing.
Again, stop at the first point where the RF is substantially lower than
the expected value because you have found a failure point.
73,
Don W3FPR
On 11/4/2013 5:01 AM, Brian Stevens wrote:
Don,
I've had another think & the low readings I get at LPF,BPF & T-R sw
o/p's using the 10Mhz oscillator are with the VFO set so that I can
hear the oscillator signal, not at 40m. Should the signal still be
attenuated under these conditions?
The low power o/p problem occurred while trying to peak the 40m BPF
inductors L1/L2 with the VFO at 7.1Mhz.
73 Brian
G0WZX
----- Original Message ----- From: "Don Wilhelm" <w3...@embarqmail.com>
To: "Brian Stevens" <br...@stevens7455.freeserve.co.uk>;
<Elecraft@mailman.qth.net>
Sent: Sunday, November 03, 2013 9:15 PM
Subject: Re: [Elecraft] K2 #7379 troubleshooting
Brian,
If the test oscillator crystal is at 10 MHz, it *should* be very
attenuated by the 40 meter Low Pass Filter.
The K2 40 meter LPF cutoff is in the range of 8.5 MHz, so it cannot
be expected to pass a 10 MHz signal.
If you have a crystal in the 40 meter band, you could substitute it
for the 10 MHz crystal and try those measurements again.
If you do not have such a crystal, go forward in the Troubleshooting
procedure to Transmit Signal Tracing and try those steps. Do not
skip the oscillator checks - VFO and BFO that are in the Receiver
Signal Tracing part of the tests.
One thing about the Signal Tracing steps - work in the order listed,
one point depends on the one before it being OK.
Once you come to the first step where the output is significantly
(greater than 10%) lower than the Expected value, stop because you
have just found the output side of the failure point - it will be
fruitless to go on to other check points.
73,
Don W3FPR
On 11/3/2013 3:53 PM, Brian Stevens wrote:
Hi,
I've hit a snag during 40m tx alignment in being unable to peak
L1/L2 to give more than about 500mW o/p with the power setting at
2W. I've gone through the troubleshooting procedure & all checks out
ok until I get to the LPF,BPF & T-R switch section of the shared
circuit testing.
Using the 10Mhz crystal oscillator in the manual with 0.14V at the
antenna i/p I get these readings:
LPF o/p @ W1 = 0.004V (expected 0.13V)
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