For 47 GHz I use the DB6NT 47GHz design. Also the LO on 11.736 MHz is Michaels design (MK3). Output 20mW in a 30cm dish and a NF of 5dB. On this page you read my procedings on this band.
Update march 21: Today I received PI7ALK in at a distance of 43 kms while I was standing at the Zeeweg in Muiderberg, locator JO22NH48.
Update march 19: received PI7ALK in JO21IP61 (20mW in a sector horn) in Velsen, JO22HK, distance 21kms. And made a QSO standing near Marken in JO22NK to PE1CKK in Muiderberg in JO22NH (13kms) over the IJsselmeer. Signals on both sides S9++.
Update january 23: Made my second QSO, over 2.5 kms with Hans PE1CKK. Signals on both sides S9+++, a nice chatty FM QSO on 47GHz!
The final setup.
Here you see te latest setup, with an OE9PMJ bandpassfilter and a DB6NT LNA. The LNA is used for RX and TX and is turned over by a big knob on the front.
A nice solid signal on the HP using my homebrew external mixer.
The output of the mixer is -6dBm including mirror, so -9 dBm just on the 47088 MHz. The filter does -5dB, this can be better. The LNA amplifies +30dB. So in theory -9-5+30=16dBm. However, the LNA has a saturation output of 30mW, in my case I reach 20mW output.
By the way, the waveguide shorting screw in the mixer module is completely removed for best results.
Using only the bare mixer I made a first QSO with John PA7JB in the pouring rain over about 200 meters over the pond. The dish size is increased to 30cm now. John used also a bare mixer with a tiny horn as antenna. Signals on both sides S9+.
During the first tests I used a small 15cm 3D printed dish made by Hans PE1CKK.
The output of the transverter is a hugh 0.25mW on both mixing products, 47GHz and mirror, so about 0.1mW on 47088 MHz. I measured this with the external mixer for my HP spectrum analyser and knowing that the small beacon using a Nord PLL on 11.772 MHz multiplied by four to get 47088 MHz gives 0.3mW output. This signal is received loud and broad.
I locked the LO of 11736MHz to 12.8 MHz out of a TCXO. The pll uses a ADF4113B and is described elsewhere on this site. I pick up the 1467 MHz with a small C somewhere around the 1500 MHz helix. The PLL needs just a very small signal. The BB105 varicap sits between the trimmer via a 5p6 C (experiment!) and ground. The pll voltage is fed to the varicap via 4k7 and decoupled with 1n. It appears that this functions in this setup as loopfilter, any additional Cs and R’ in de the loopfilter on the PLL board make it unstable and oscillating.
Ready for the first test outside the shack. Still using the small 3D printed dish, 15cm prime focus. An Yaesu FT290 is used as 2m IF transceiver..
Here the 12.8 MHz TCXO ia shown, including its 7805. Space is left on the small board to add an Atmel if I ever want to lock it to GPS 1pps..
