after being motivated by my first RX attempts (thanks to lots of support in this forum), I started getting my TX path together. I received all ordered components last week, put them together in an on the fly setup on the balcony yesterday, and started my first TX attempts
With a couple of successful CW QSOs, I managed to "limp" successfully over the NB transponder. Responding to a CQ call in SSB was unsuccessful, but at least the OM reported back that "the signal of the HB9 station" was barely readable. So I know at least that I am at the bottom end with my current setup.
The 72cm dish is set up for best RX signal. When I mount the Helix feed on the LNB, the RX signal goes down by approx. 2 dB. I can hear my own TX signal on the WebSDR in Goonhilly weak but clear. With my own RX setup, I can hear that there is something in the noise. (QSOs are possible without cheating by using the WebSDR for RX). There is certainly room for improvement, but the RX path is sufficient for QSOs and has no priority for the moment.
I use a SG-Lab transverter with 2W output. The short SMA to BNC jumper cable connected to the Feed with an BNC to N jumper probably attenuates an extra 2 dB (It's made in China, out of my "just in case" adapter box with adapters which I collected without any specific purpose) so with a proper low loss jumper and high quality connectors, I can probably recover 1-1.5 dB in the UL path.
My biggest worry is the TX antenna path: The dish is set up in a corner of the balcony. Approx. 1m in front of the dish, directly in the signal path, there is a vertical steel support of the balcony, which goes from the ground floor through the balcony of the upper floor.
I can "see" QO-100 just above the corner of the building. The options to move it are limited, just a bit to the back before the upper balcony obstructs the path to the satellite. Unfortunately, I have no option to mount the dish outside the balcony to avoid the steel structure. Putting a larger dish to the same place is not possible, either.
At the first look, a 20W PA would probably solve my problem, however with an unknown amount of RF being reflected randomly. Has anybody got any experience with obstacles in the TX path with an estimation, how many dB could get lost due to this steel structure?
Possible alternatives for a TX antenna would be a panel mounted to the steel structure itself, or a Helix pointed to the satellite close besides the steel structure. I am aware that both options have their issues. Any ideas if these alternatives would be a viable solution for 2W TX power?
73 de Jens, HB9EKO