K3 transceiver driving an Anglian transverter from G4DDK, with the PA
module producing up to 8W output at 144MHz. This drives a DB6NT
23cm transverter (MKU13G3) running about 3W.
This drives a PE1RKI
module amp which then drives a linear to 150W output. About 70W reaches the antenna, a Wimo
44ele yagi at 13m agl.
I have built a masthead
preamp, details as follows:-.
The completed PCB is shown here
. I bought a cheap microscope to help put the SMD components in.
After several disasters I have ditched the 24V coax relays in the preamp box (see picture here
as they seem unreliable, indeed some of them have a tendency to stick
on receive when powered for transmit - the preamp does not survive
The new layout (here
uses a 12v Ducommun 2N1B11 relay with a separate feeder for
transmit. The relay is specified as handling 270W at 1.3GHz and
has measured isolation of about 70dB.
I have modified my sequencer (based on the W6PQL
design) to accommodate both 12v and 24v relays. My sequencer
drives the relays and the 12v bias supply to the PA. Schematic is
The complete transverter is shown here:
The interior view shows (left to right) 28V 13A PSU, 23cm filter, DB6NT
transverter, relay drive circuit (now replaced with sequencer), PE1RKI
module amplifier, PE1RKI PA and fan.