23cm equipment


23cm system

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.

DB6NT transverter

                                         DB6NT transverter

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.

PE1RKI 23cm amp

PE1RKI amplifier

I have built a masthead preamp, details as follows:-.
Circuit is due to OZ2OE
PCB supply is from rfextra
SMA connectors and adaptors are from chinarf
Layout diagrams are here and here

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 this.  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 here.

The complete transverter is shown here:
Transverter exteriorTransverter interior
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.