I appreciate all the feedback I'm getting on my query. To provide
context, here's a brief description of how my station is organized:
Since moving to North Carolina from Texas in early 2020, until recently
my antenna complement consisted of two wire antennas. The first is an
80-40 inverted vee at about 50' center height. This consists of a common
center insulator/balun (DXE 5kW) with separate 80 and 40 meter
elements. This antenna is fed to a 500W LBS 80-40-20 Triplexer (the
original antenna design also had a 20 meter element, but it never worked
very well). The station antenna switching control also allows bypassing
the Triplexer and feeding the antenna directly to the antenna switch so
the inverted vee can be used on the WARC bands. The second antenna is a
Hy-Power 20-15-10 dipole (3 separate dipole elements arranged in a cage
configuration with a common feed) at about 25'. This tri-band dipole is
fed to a 500W LBS 20-15-10 Triplexer to provide isolated outputs for the
three bands.
The six antenna ports available from this arrangement are switched by a
microHAM Double Ten 2X10 switch to allow SO2R capability. The A and B
outputs of the antenna switching assembly each feed the Antenna port of
an Elecraft KAT500 ATU unit, which is used as a "line flattener" for
the normal contest bands and as a tuner for the WARC bands. The ATU
Transmitter ports feed the A and B Antenna ports of a TX BPF assembly
consisting of a bank of six LBS 500W bandpass filters with a KK1L design
2X6 switch at both input and output. This provides an interlocked TX BPF
selection for both radios. There is also provision for bypassing the
filter bank for use on the WARC bands.The two BPF Transmitter ports are
in turn connected to the RF output ports of their respective KPA500
amplifiers.
The station RF components have been carefully engineered to maximize
isolation between the two radios. Double shielded coax is used
exclusively and much attention has been paid to layout to minimize
coupling. Each receiver chain has protectors in both the Main and Sub RX
antenna inputs. I can operate either radio within about ±20 kHz of the
other radio's second harmonic in SO2R mode at 500W output.
In September of this year I finally completed the installation of a JK
Mid-Tri 40 on a 70' crankup tower. The triband portion of the JK is
split using a LBS 1500W 20-15-10 Triplexer. The resulting 40, 20, 15 and
10 meter ports are then switched using a 4O3A 2X8 switch. This hardware
is located in a detached garage about 120' from the house. The A and B
outputs from the 2X8 switch are fed to the entry panel at the house by
1/2" hardline runs. The antenna switching assembly in the shack was
modified to allow selecting either the local or remote feeds to the ATU
Antenna 1 and Antenna 2 ports,respectively.
I had originally intended to keep the station at the 500W level, but
operating Sweepstakes and CQWW SSB using a decent antenna has convinced
me that if I really want to be competitive in the High Power class of
the various contests I need to make up the 4+ dB power deficit to the
full power stations. The $/dB investment is rather breathtaking, but I
think I'll bite the bullet and do it. I'll probably upgrade only the
Radio A amplifier, since the vast majority of my operation is SO1R mode.
In researching available RF hardware to handle the increased power, I
found a source for the high power bandpass filters, but not the duplexer
and triplexer. It appears VA6AM will build the multiplexers I need. I
didn't realize this, so I greatly appreciate the recommendations. I'll
definitely contact him and see what can be done. Again, thanks to all
for your assistance.
73...
Randy, W8FN
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