Last Contact to Switzerland HB9 on 3.4 GHz EME
On Friday 27/10/2023, FRARS G4RFR was put on 3.4 GHz EME with a view to working Dan HB9Q for a first and last time before the Swiss authority removes the band for them. The QSO was successful and now marks one of the last QSOs with the Swiss on 3.4 GHz.
We responded to Dan’s request for a last time opportunity by using the 3.65 m prime dish and fitting the refurbished 3.4 GHz system.
Julian G3YGF, John G0API and Tony G3PFM were present and made the contacts.
This consists of a purpose built feed box “sled” which contains a circular polarised waveguide feed designed to provide approx 25 dB of isolation between the TX and RX ports. On RX the first stage is a G4DDK 0.45 dB low noise pre-amp, followed by a waveguide based Evanescent band pass filter and then a GaAsFET second stage .
A commercial transverter (DownEast) forms the back end and down conversion to 144 MHz I.F.
On TX our usual 10 GHz IC-746 rig generates the WSJT Q65 or CW drive to the TVTR, which is mounted in a tote bin just under the dish rim. On the sled are a pair of 50 W Toshiba PA modules and matching SWPSU, supplied at 240 V input. The PAs are phased together and produce around 45 W currently (one module is running well under nominal power out) .
Control is provided by an onboard sequencer and backed up by our usual 10 GHz sequencer system .
The dish is controlled by our bespoke Medii software and at 3.4 GHz the -3 dB (half power) beamwidth is approximately 1.8 degrees, so a lot less critical than the 0.5 degree we usually see at 10 GHz .
The tracking worked without any error or need for input from us during the 3 Hr session, which is just as well as the Moon on the boresight camera kept being obscured by ominous rain clouds .
The entire log from the session is below.
27-10-2023 40W G4RFR 3.4GHz HB9Q 19:03Hrs 3400.100 -5 sent/ -4 rcvd Q65C JN47 24dB S/N in 6Hz 10m/100W HB9Q 19:12Hrs 3400.100 559 sent/ 559 rcvd CW DL4DTU 19:30Hrs 3400.095 -12 sent/ -12 rcvd Q65C(JO60)15dB in 6Hz 4m6/75W DL3WDG 19:35Hrs 3400.095 -16 sent/ -11 rcvd Q65C JN68 his best -13 2m4/65W DL1SUZ 19:42Hrs 3400.095 -17 sent/ -16 rcvd Q65C JO53 10dB S/N in 6Hz 3m2/45W DB6NT 19:58Hrs 3400.140 539 sent/ 559 rcvd CW 3m7 100W Circ PE1LTR 20:20Hrs 3400.100 - sent/ - rcvd Q65C Nil 1m5/45W
Article by John G0API, 28/10/2023.