Working on 10GHz
Posted: Tue Jun 08, 2021 7:24 pm
Having recently received a spare Bullseye LNB ($29.99 delivered from RTLSDR shop via AliExpresss) I set about giving it some gain for portable use. From my stock I extracted a BNIB BSB Mini-dish and had a look at the kit contents. The original LNB was not plastic encased like the modern variety so suits a 22mm round 'pipe'.
Removing the plastic case from the Bullseye (6 plastic clips that can be gently prised open) revealed just that, a round body of approximately 22mm diameter, with some of a box assembly for the electronics getting slightly in the way. By splitting the original BSB LNB boss in half and carefully grinding away plastic (glass filled nylon I think, good stuff) it was possible to mount the LNB as BSB intended.
Mounting the dish on a suitable cross-bar and tripod, I pointed it at the sun and experimented with the angle until the centre cap was illuminated by the suns image. So pretty much at the focal point then
With RX sorted I moved to TX, hoping to use my Pluto's 5th harmonic and amplifying it a bit. I recalled I bought a "dish feed to WG16" from Bob Platts about 20 years ago, this fits directly into the LNB mount with a few turns of tape to give the holder some grip. Just got to build/convert an old Gunn diode 10GHz cavity to SMA feed and I'll be good to go.
Both dishes can be mounted as shown, or a bi-quad feed for 3.4 can quickly be substituted to the TX dish if I want to use 9cms.
All good stuff....
Gareth
Removing the plastic case from the Bullseye (6 plastic clips that can be gently prised open) revealed just that, a round body of approximately 22mm diameter, with some of a box assembly for the electronics getting slightly in the way. By splitting the original BSB LNB boss in half and carefully grinding away plastic (glass filled nylon I think, good stuff) it was possible to mount the LNB as BSB intended.
Mounting the dish on a suitable cross-bar and tripod, I pointed it at the sun and experimented with the angle until the centre cap was illuminated by the suns image. So pretty much at the focal point then
With RX sorted I moved to TX, hoping to use my Pluto's 5th harmonic and amplifying it a bit. I recalled I bought a "dish feed to WG16" from Bob Platts about 20 years ago, this fits directly into the LNB mount with a few turns of tape to give the holder some grip. Just got to build/convert an old Gunn diode 10GHz cavity to SMA feed and I'll be good to go.
Both dishes can be mounted as shown, or a bi-quad feed for 3.4 can quickly be substituted to the TX dish if I want to use 9cms.
All good stuff....
Gareth