10GHz - getting ready....
Posted: Mon May 09, 2022 6:39 pm
After successfully running up my Polish-sourced 10GHz CBBN 1W transverter on Friday I've progressed to sorting out a dish feed and spare dish for separate RX.
I picked up a skip-bound large SKY dish recently, unfortunately missing its LNB arm. A wanted request on this forum produced the required measurement (Thanks Steve G4HTZ ) and some 3-D printed spacers allowed stock 3/4 aluminium to be used for the boom. An LNB mount from unknown origins fitted, with slightly different spacers, the same being required for the actual LNB, a Bullseye devoid of its outer casing (previously removed to fit it perfectly onto a BSB mini-dish.
For a 10GHz source, I used a cheap eBay ADF4351 board with built-in LCD and keypad. Other than showing mHz, it works well. I set it to 3.460GHZ (x3=10.380GHz) and fed its output through a pipe-cap filter kindly tuned for me by Dave G8GKQ at last summers CAT21. This fed directly into an 'adapted to SMA' WG16 commercial feed.
Picture shows it down in the garden shed doorway.
For RX I used Langstone as the main task was to check the dish angles L+R and U+D. The signal was soon found at 630.160MHz (10.380-9.750 + a bit of reference difference) and the dish duly tweaked. At this point I had a huge signal, so wound the Langstone gain all the way down to -1dB at which point I had about the right level of signal for peaking.
What was interesting was seeing what I THINK is phase noise, unlike a clean CW carrier, I had that but additional little squiggles either side of a random nature - almost like ssb speech looking. I think I read somewhere that above 2GHz, this chip is prone to this. In the transverter, the LO will be running at 2.012GHz (x4 +TX & RX IF) so it may not be as much of a problem. Additional supply filtering does improve on this, low ESR capacitors ready to fit.
After establishing that I needed a few more degrees down-tilt capability and drilling alternative mounting holes, I fitted the dish to my 'TOM' and tested out the elevation/azimuth adjustment. Very nice, its going to be a very handy dish. Tomorrow I make a G3WPO offset dish feed and circular 22mm copper launcher from SMA, followed by more tests. The transverter has already done DATV 'across the shack' and the option of using a second dish and LNB might improve the RX capability. Testing will tell.....
Gareth
I picked up a skip-bound large SKY dish recently, unfortunately missing its LNB arm. A wanted request on this forum produced the required measurement (Thanks Steve G4HTZ ) and some 3-D printed spacers allowed stock 3/4 aluminium to be used for the boom. An LNB mount from unknown origins fitted, with slightly different spacers, the same being required for the actual LNB, a Bullseye devoid of its outer casing (previously removed to fit it perfectly onto a BSB mini-dish.
For a 10GHz source, I used a cheap eBay ADF4351 board with built-in LCD and keypad. Other than showing mHz, it works well. I set it to 3.460GHZ (x3=10.380GHz) and fed its output through a pipe-cap filter kindly tuned for me by Dave G8GKQ at last summers CAT21. This fed directly into an 'adapted to SMA' WG16 commercial feed.
Picture shows it down in the garden shed doorway.
For RX I used Langstone as the main task was to check the dish angles L+R and U+D. The signal was soon found at 630.160MHz (10.380-9.750 + a bit of reference difference) and the dish duly tweaked. At this point I had a huge signal, so wound the Langstone gain all the way down to -1dB at which point I had about the right level of signal for peaking.
What was interesting was seeing what I THINK is phase noise, unlike a clean CW carrier, I had that but additional little squiggles either side of a random nature - almost like ssb speech looking. I think I read somewhere that above 2GHz, this chip is prone to this. In the transverter, the LO will be running at 2.012GHz (x4 +TX & RX IF) so it may not be as much of a problem. Additional supply filtering does improve on this, low ESR capacitors ready to fit.
After establishing that I needed a few more degrees down-tilt capability and drilling alternative mounting holes, I fitted the dish to my 'TOM' and tested out the elevation/azimuth adjustment. Very nice, its going to be a very handy dish. Tomorrow I make a G3WPO offset dish feed and circular 22mm copper launcher from SMA, followed by more tests. The transverter has already done DATV 'across the shack' and the option of using a second dish and LNB might improve the RX capability. Testing will tell.....
Gareth