[Elecraft] 6m birdies and K3S and/or new synth boards
Jim Brown
jim at audiosystemsgroup.com
Tue Jun 23 14:11:21 EDT 2015
On Tue,6/23/2015 10:44 AM, Brian Hemmis wrote:
> David, Your friend states there are 2 dozen birdies on 6 meters with the antenna DISCONNECTED. This tells me nothing. Please tell him to connect a RESONANT 6 meter antenna to the radio then tell me how many birdies he hears.
It tells me a LOT. With no antenna connected and a 50 ohm resistor
across the antenna input, I hear birdies on 6M from my station logging
computer. That tells me that the K3 has a Pin One Problem on one or more
of the dozen or so connectors to which I have cables connected -- DC
power, Aux power out (for P3), audio I/O, mic, headphones, IF out to P3,
RX antenna in, AUX antenna in, paddle, amplifier key line, AUX cable,
and RS232 cable. With the antenna connected and pointed away from the
shack, these birdies are at least 6 dB above band noise when the band is
quiet.
This is in addition to the birdies generated within my K3s that move
around as the main RX is tuned. Interestingly, I do NOT see birdies
related to the SubRX. Those moving birdies are a real PITA -- I use the
P3 to look for weak CW signals during double-hop E-skip openings, and
those internally generated moving birdies look just like those weak CW
signals. This greatly reduces the usefulness of the P3 on 6M.
Installation of the new synth boards has not changed that. Although the
preamp in the KXV3B may have reduced my noise level a bit, I had an
outboard GasFET preamp before installing it, and heard the birdies with
it too.
73, Jim K9YC
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