The microwave repeater in the sky , AMSAT QO-100: The IF receiver section has been built and tested, just a 739 MHz downconverter
to the first IF of the 70cms section of the main HB rig, The 1mtr dish is in position and the POTY and Octagon PLL LNB , are nearly ready
very kindly machined by Neil G4DBN.
See this link for POTY details:-Patch antenna details Other interesting stuff as well.
The 10GHz downlink Rx section is the easy bit , the 2.4GHz uplink, will be require an up mix from 70cms, I have the up mixer and SSPA boards
they just require building up, shouldn't take long if I don't get distracted and I will probable use a SV1AFN ADF4351 Synth board for the 2116 MHz LO.
I've also added general coverage Rx to the main Homebrew Multimode Transceiver, this already covers 50, 70 144 and 432 MHz
It now also covers as a general coverage Receiver, 100KHz to 30 MHz, as well as the 10.45 GHz downlink from the QO-100 satellite .
13cms masthead transverter also had water ingress and that is WIP , doesn't look like any damage was done, but will need external repainting.
The 6cms masthead transverter has had a mishap with the British weather, water had got in and the driver stage to the 15W SSPA died
I found a commercial module which for -12dBm in gave +29dBm out, I had never used it as running on +12v the output was low, but on +15v
the full output was realised. That was fitted and with a lot of snow flaking 10W out.
This is a simple design , that the software has caused a few problems due to the I2C routines, I found out why most
people use more complex PICs that have the routines built in. I chose to use the PIC12F629 as it is about the same physical
as the Si571 synthesiser.I did find however that using this at 9 MHz produced modulation that was slightly compressed
However , the solution was very simple, use two boards, replace the Si571 on one of the boards with a Si570 as modulation only
The schematic for this board is here
needs to be applied to one device, On my main rig I used the Si571 at 93 MHz and the Si570 at 102 MHz , and then driving straight in to
a Level 10 DBM gives and very good 9 MHz modulated source. the sum at the mixer is easily filtered. This can be use d to generate
NBFM at any HF frequency , and the maximum deviation obtainable was in excess of 25 KHz.
The source code for the PIC Here
The Eagle schematic Here :Use save link as
The Eagle board layout Here :Use save link as
A test program to keep writing to the Si57x ,wait for a ACK and loop, scope sync on pin5 Here
Very useful for checking I2C timing. A README file is Here
Apart from the Voltage regulators to supply the +5V and +3.3V , an LM6211 is used to provide pre-emphasis and to set the
the mid rail bias point to the Si571, this allows the deviation +ve and -ve peaks to be balanced.
The same board can be used a single frequency source, there are four user selectable frequencies in the software to control the Si57x
All the software for the Modulator board and the control software for my two homebrew transceivers has been written by my very good
Buck , KD8RRI. I would have been stuck without his help, as I'm still not yet fully conversant with C programming.
In the Files section there is a zipped bundle of the assembly code for the PIC12F629 as well as the Eagle schematic and board layout
I've also included in the files section the control software written by Buck for the WD6DHW AD9912 DDS board.
there are two versions I use both drive a 16x2 LCD display and use an optical shaft encoder for tuning,
and lower cost mechanical encoder is used for RIT.
The main rig is multi-band and now multi-mode, covering 50MHz, 70 MHz,144MHz and 432 MHz All the stages are inboard.
The smaller rig is used as the IF for the microwave bands, transverters are all external, The band selection on this
rig built into an old thermal printer case, controls the selection of Local oscillators , locked to a Rb source, the power,
and IF feed at 144 MHz to the rig.
This arrangement works very well as I can QSY between bands at a push of a button on the front panel of the transceiver.
KD8RRI R2PRO/T2PRO Transceiver
Sadly Buck, KD8RRI, passed away in Sept 2015. His work on a transceiver using the WD6DHW AD9912 board is here.
All the details , schematics , notes and software for this transceiver are in the files section for download.
1 GHz Clock Source.pdf
LO- Aux Control.pdf
LO Control & LCD Wiring.pdf
LO- Quad Gen-1.pdf
LO- Quad Gen-2.pdf
LO S-P Interface.pdf
R2Pro_9912_3q.asm (use "save link as")
R2Pro Documentation Package.pdf