Like with any amateur radio station the equipment and antennas are always in a state of flux, with constant improvements being wanted to seek out that bit of DX or dB advantage. With satellites it’s no different you always want that extra bit of signal to work that station on the edge of the footprint.
Last week saw me implement some further changes to my home AMSAT ground station; anyone who follows me on Twitter will know the last couple of months has been quite challenging after suffering quite a few minor heart attacks so in theory, I’m meant to be resting till I see my heart specialist in a couple of weeks but I never stick to the rules.
Let the changes begin!
First changes was remove the Wimo X-Quads off the short mast in the garden. Which thankfully just requires climbing on the wall to reach them although that’s strike one for not following orders. I will admit knowing the risk of blacking out at a moment’s notice was a little bit scary!
However I got the task done, removed the x-quads and disconnected the phasing harnesses ready for connecting the new polarity switching system; this was made by Gavin M1BXF and based on the design on G6LVBs website. connect the new SHF-Elektronik preamps.
In fact doing those parts was probably the easiest, as I’d also bought two 15m runs of LBC400 coax to replace the old stuff which needed to be routed from the mast to the shack; thankfully this was completed with some help from Dad (M3JFM).
Early signs after completing the work is promising; can hear the satellites down to lower elevations, the fading is far more controlled being able to switch polarisation and in 4 days I’ve made 45 satellite QSOs on the improved setup.
The only things now left to change is adjusting the preamp gains 70cms is perfect, 2m is a little high and needs pulled back a bit. Another thing that needs added is a 70cms bandpass filter as I’m noticing some desense issues but again all these things can be tweaked in the coming weeks.
Next task is to decide what changes to implement inside the shack, I’m still undecided to whether there is any real advantage to replace the ICOM IC-910 with a IC-9100, what I’d love to see is someone build a duplex 2/7/23cms SDR similar to the flexradio HF range that would certainly add some benefit to the station but not seen anything yet.
Nice one peter
Great to see your Antenna set-up its what i’m going to be installing soon
i’ve got the G-5500 Az/El rota with LVB tracker from Amsat USA
i have to place my order from Wimo for the Xquads plan to add the Pol switch at
later date be interested in what you had built.
mines based on the design on G6LVBs website nothing special.
What kind of 70cms bandpass filter are you using?
I d`ont use enything, i d´ont have pre amps too…only use the TS2000 preamp.
The antennas are from Wimo.You can see them in the photo QRZ.com.
Crossed Yagis for 2m and 70cm 2×10 and 2×18 from WiMo
I picked up a duplexer and used that todo the filtering.
Hi Peter
Great setup. I also have the same setup. I do have the remote polarisation from wimo as well. Those are not mounted yet. I will
have to make the switch box first, and the cables. Right now I am using the fixed rh circular polarisation and the wimo phasing harness.
I can see on the picture that you seem to have the same lenght from both antennas into the remote polarisation. I know the 2m antenna just need same length, but the 70cm in horisontal lenght needs to be longer, due to velocity factor. L/4xvelocity factor than the cable for the vertical plane. What did you do here?
But I am having issues reaching the satelites currently, I cannot hear myself in birds running the Ic9700.