The nice thing, the K3S which contains the new synthesizers and
a K3 updated with new synthesizers will be cleaner due to lower
phase noise and amplitude noise. Otherwise, lower composite
noise which does and will affect any receiver. Receiver
filtering will not reduce the type of noise which exists in the
passband of the receiver. If the transmitter is dirty,
everybody suffers. It it is fed through an amplifier, everybody
Please read Rob Sherwood's article in QST, November 2019, pp 38 -
41. "It's Time to Clean Up our Transmitters". You may discover
that the wonderful radio you just purchased may not be so
wonderful after all.
On 11/3/2019 11:32 AM, Wes wrote:
If TX IMD is the issue, K3 and K3S
transmitters are a real mixed bag. My old K3 at 30 watts is
fantastic, with IMD at all frequencies better than -40 dBc (ARRL
method). The same radio at 10W is the worst of my two radios,
except at 24 MHz where the K3 and K3S tie at -22 dBc.
It's been hard to keep up with these
measurements since the KLPA3A in the K3S has been replaced twice
and the KPA3A is IIRC, on the fourth version.
On 11/3/2019 8:16 AM, Martin Sole
I suspect the quality of
the transmitter particularly with regard to its composite
noise spectrum to be a large player. Some radios with high
end receiver performance have rudimentary (I'm being kind)
transmitter composite noise performance.
See what NK7Z, NC0B and K9YC have written about this.
On 03/11/2019 21:30, Mark Morin
My experience is that the type of rig does make a difference
for close coexistence. We’ve found on DxPeditions that an
upgraded K3 with KPA500 and a Kenwood TS-590s also with
KPA500, can coexist quite well with antennas about 300 ft
apart. On most bands, we can operate SSB and CW simultaneously
with tolerable QRM. Other times we have tried different
high-end rigs in similar setup and found that opposite end of
same-band operation was nearly impossible due to QRM. I
suspect it’s mostly the receivers that makes the difference.