A portable mode V/S antenna setup was constructed in order to work the AO-51 satellite in mode V/S, uplink on 145.880 MHz, downlink 2401.200 MHz. Both uplink and downlink in FM, so the Doppler correction on 2.4 GHz is really a challange around the TCA (time of closest approach.).
The 145 MHz part of the famous Arrow was used, with a custom made mounting for the S-band downconverter from Kuhne Electronic GmbH. A bias-T was used to power the downconverter. The patch was soldered for RHCP (the original instructions were for LHCP). The semi-water-proof was made of an empty salad box (the cucumber version works fine :-)).
The set up was succesfully used on AO-51 mode V/S. Several contacts were made with two FT817NDs, and a Heil headset. All powered from a single 2.2 Ah battery.
Thanks to John G7HIA for providing the patch antenna, David G0MRF for providing the 2.4 GHz source for testing, and AMSAT-UK in general for selling these items (and doing all other good things).
Here are some pictures from the antenna setup.
The complete antenna, the 70 cm part of the Arrow is removed, the 3 elements 2 m part is unmodified.
The 2.4 GHz parts are mounted on the Arrow boom through the existing holes of the 70 cm elements.
The 2.4 GHz patch, the downconverter (MKU LNC 24 OSCAR 2 TM) and the bias-T (KU BT 271 N), both from Kuhne Electronic GmbH.
A creative way of positioning the patch antenna by using a 90 degree N angle connector. The standard Arrow duplexer is not used and therefore removed from the antenna.
The patch antenna with the semi-water-proof box removed.
Again some creative mounting constructions, but it all works.
A YouTube Video
A YouTube video was made by EB4FBZ showing his 2.4 GHz receiving capabilities, but also showing my downlink signals (PA1IVO/P at 0:25 and 0:46) in Spain at the same time.